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829 terms

Genomic Biology

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In eukaryotes, during S-phase of the cell cycle, the DNA of all chromosomes is replicated using mechanisms relatively similar to those of bacteria. What in addition to the new DNA strands must be made during S-phase to permit the synthesis of the new sister chromatids?
two new strands of DNA for each chromosome, and enough histone 2A, 2B, 3, and 4 to double the number of nucleosomes that existed before replication
The study of which genetic disease led Garrod to propose that there is a special relationship between genes and enzymes?
alkaptonuria
The one-gene, one enzyme hypothesis was proposed by ___ in 1942.
Beadle and Tatum
The test organism that helped researchers elucidate the one-gene; one enzyme hypothesis was
Neurospora crassa
Mutant strains of a bacterium that are unable to grow on a minimal medium are
auxotrophic
A methionine auxotroph
can grow on minimal medium supplemented with methionine
The frequency of PKU in Caucasian populations is approximately
1/10,000
In PKU, the absence of enzyme activity effects which step in the phenylalanine metabolism pathway?
conversion of phenylalanine to tyrosine
The Guthrie test for PKU requires the use of which microorganism?
Bacillus subtilis
Phenylketonurics are advised to avoid the artificial sweetener Nutrasweet because it contains
phenylalanine
The normal version of the mutant gene responsible for albinism in humans encodes an enzyme that converts
DOPA to melanin
The mutant gene responsible for PKU is located on
chromosome 12
Which disease is caused by a mutation in a gene located on the X chromosome?
Lesch-Nyhan syndrome
The most severe form of Lesch-Nyhan syndrome affects
males only
Which of the following is characterized as a lysosomal storage disease?
Tay-Sachs disease
The mutant gene responsible for Tay Sachs disease is located on
chromosome 15
The mutation responsible for the sickle cell disease affects ___ in the hemoglobin gene.
a single base pair
A person who was homozygous for the recessive mutant allele h, and was IAi at the ABO locus, would have which blood type?
O
Which gene is responsible for the expression of blood group antigens on the surface of red blood cells?
H
A child born to a man and a woman who are both carriers of the mutant allele responsible for cystic fibrosis has a ___ chance of having the disease.
25%
The frequency of cystic fibrosis in Caucasian populations is ___ the frequency of the disease in people of African descent.
greater than
A heterozygote with a mutant allele for phenylalanine hydroxylase would have which phenotype?
none of the above
Genetic counselors determine the risk of a genetic disease in a family by first performing
pedigree analysis
Cystic fibrosis is caused by a mutation in the gene that encodes which enzyme?
CFTR protein
In people who do not have Tay-Sachs disease, the hexA gene encodes an enzyme that
cleaves acetylgalactosamine from gangliosides
Sickle-cell disease is caused by a mutation that affects which type of cell?
red blood cells
Among Caucasians, the most common lethal autosomal recessive disease is
cystic fibrosis
A bacteria that is a histidine auxotroph should be grown on a medium that
contains histidine
The mutation responsible for cystic fibrosis occurs in a gene that is located on which chromosome?
7
The genotype for a person with type O blood is
i/i
A person with sickle-cell trait has ________ at the beta-globin gene locus.
one wild-type and one mutant allele
Two people who are considering having children see a genetic counselor, who determines that they are both heterozygous for a deleterious allele. The counselor advises them that their risk of producing a child with this genetic disease is
1/4
The following is a representation of a metabolic pathway involving genes for enzymes A, B, C, and D:
A -----> B -----> C -----> D -----> product
A mutation in the "B" gene would result in an accumulation of which gene product?
A only
A person with the genotype IA/i H/h would have which blood type?
A
Tay-Sachs disease is most prevalent in which population?
Ashkenazi Jews of central European descent
In Caucasian populations, approximately 1 out of every ________ people is a carrier for cystic fibrosis
20
The Nobel Prize-winning researchers who are credited with determining that one enzyme is produced from one gene are
Beadle and Tatum
A person with PKU
accumulates phenylalanine in his or her tissues.
Individuals who are homozygous for the h allele have which blood type?
O
In 1902, Archibald Garrod and his colleague William Bateson performed experiments which indicated that
there is a link between genes and enzymes.
Lesch-Nyhan syndrome is caused by a mutation in a gene located on which chromosome?
X
The mutation responsible for sickle-cell disease is a(n)
point mutation in the beta-globin gene
The genes in the ABO locus encode
glycosyl transferases
Which metabolite is required for normal production of the skin pigment melanin?
phenylalanine AND tyrosine
The genes for hemoglobin S and hemoglobin A are
codominant
A mutation in the gene for which enzyme is responsible for the metabolic disorder phenylketonuria?
phenylalanine hydroxylase
Which of the following is characterized as a liposomal storage disease?
Tay-Sachs disease
Amniocentesis is best performed
after the twelfth week of pregnancy
Chorionic villus sampling is best performed during which stage of pregnancy?
during the first trimester
A man and a woman, both with blood type O, get married and have a baby whose blood type is A. The man claims that he can't be the baby's father and asks for a divorce. The woman, whose genotype is H/H, i/i, insists that the child is his. For her husband to be the father of the baby, his genotype must be
h/h I to power of ((A))/i
The compulsive self-mutilation behaviors exhibited by Lesch-Nyhan individuals are the result of a mutation in the gene for which enzyme?
hypoxanthine guanine phosphoribosyltransferase
It is possible to distinguish between normal hemoglobin and hemoglobin S using electrophoresis because these two forms of hemoglobin have different
electrical charges
Bottles of Diet Coke carry a warning for people with PKU because the sweetener used in this drink contains
phenylalanine
Which of the following human diseases is caused by an autosomal recessive mutation?
phenylketonuria, cystic fibrosis, alkaptonuria, albinism
The mutation that changes normal hemoglobin to hemoglobin S changes a codon for glutamic acid to one for
valine
In a molecule of hemoglobin C, an aspartic acid residue, is changed into a ________ residue.
lysine
A child born to a man and a woman who are both carriers of the mutant allele responsible for cystic fibrosis (CF) has a ___ chance of having the disease.
25%
A methionine auxotroph
can grow on minimal medium supplemented with methionine
The autosomal disease with the signs of sinus and lung abnormalities, sterility, and sometimes dextrocardia (heart to the right of body center rather than left) is
called Kartagener syndrome and are all related to the malfunction of cilia and flagella that results from the failure of dynein motor proteins to function properly
In PKU, the absence of enzyme activity affects which step in the phenylalanine metabolism pathway?
conversion of phenylalanine to tyrosine
The one-gene-one-enzyme idea was replaced with ______________ as knowledge of gene structure improved.
one-gene-one-polypeptide
People with phenylketonuria are advised to avoid the artificial sweetener NutraSweet because it contains
phenylalanine
Women have two copies of the X chromosome, whereas men have an X and a Y chromosome. Sons always receive their X chromosome from their mother. Lesch-Nyhan syndrome is caused by a recessive mutation of a gene on the X chromosome that codes for hypoxanthine guanine phosphribosyl transferase, and that is a lethal gene. A woman heterozygous for the Lesch-Nyhan allele could have an affected
son, and grandson through her daughter
"Inborn errors of metabolism" is a phrase coined by British physician Archibald Garrod in 1908. This phrase refers to
defects in metabolic enzymes
The mutant gene responsible for Tay-Sachs disease is located on
chromosome 15
Although at least three genes are known to cause albinism, the classical mutant gene responsible for albinism in humans encodes an enzyme that converts
tyrosine to DOPA
The one-gene-one-enzyme hypothesis was proposed by ___ in 1942.
Beadle and Tatum
The study of which genetic disease led Garrod to propose that there is a special relationship between genes and enzymes?
alkaptonuria
The test organism that helped researchers elucidate the one-gene-one-enzyme hypothesis was
Neurospora crassa.
Which disease is caused by a mutation in a gene located on the X chromosome?
Lesch-Nyhan syndrome
The disease cystic fibrosis results from a defect in the Cystic Fibrosis Transmembrane Regulatory protein. Which of the following statements about the CFTR protein is FALSE?
The most common mutation causing cystic fibrosis is a deletion of a single nucleotide at position 508. This causes the deletion of a phenylalanine nucleotide at that position.
The met2, met3, met5, and met8 mutants of Neurospora all have been shown to require the amino acid methionine for growth. All of these mutants show the same phenotype when they are grown on minimal medium containing which of the following?
methionine
Mutations in genes that disrupt metabolism have been investigated for nearly 100 years, beginning with Garrod in 1902. In a model genetic organism, Neurospora, Beadle and Tatum studied biochemical mutants that were unable to grow because they could not make enzymes required to make specific metabolites. By investigating inborn errors of human metabolism, we know that often the absence of enzymes leads to the accumulation of products that cannot be eliminated and generate toxic pleiotrophic effects. Which of the following statements best explains this difference between metabolic mutations in Neurospora versus humans?
Neurospora is prototrophic and must make all of the metabolites that are essential for its growth, whereas humans are auxotrophic and require that essential metabolites be provided in the diet. Therefore, the ability to minimize the accumulation of toxic metabolites in humans is more critical to the survival of the organism.
Tay-Sachs disease is a lysosomal storage disease resulting from the lack of an enzyme called N-acetylhexosaminidase A. What are the pleiotrophic phenotypic effects associated with the deficiency of this lysosomal enzyme?
-sensitivity to sharp sounds and a red spot surrounded by a white halo on the retina of the eye
-paralysis and blindness
-loss of hearing and feeding problems
-ALL OF THESE
The most common allele associated with sickle-cell disease is the Hb-S allele. Which of the following statements about sickle-cell disease is FALSE?
-Sickle-cell disease and related forms of anemia result only from mutations in the beta chain of hemoglobin, but never from mutations in the alpha chain.
-All mutations affecting oxygen-transporting properties of hemoglobin are associated with changes in the electrophoretic properties of hemoglobin.
-The sickle-cell trait results from mutations in genes coding for the alpha subunit, whereas individuals with sickle-cell disease bear mutations in the gene coding for the beta subunit.
-ALL OF THESE FALSE
The term "pre-mRNA" refers to ____________________.
new, unprocessed mRNA of eukaryotes
During transcription, RNA polymerase joins nucleotides ____________________.
from 5' to 3'.
-Just as in DNA synthesis, RNA polymerase catalyzes the formation of a bond between a 5' phosphate on one nucleotide and a 3' hydroxyl on the next. Thus the chain grows from 5' to 3'.
In bacteria, RNA polymerase transcribes ____________________.
all types of genes
In translation,
RNA is converted to protein
Match the RNAs below with their function. Use each answer only once.
___ mRNA (a) Facilitates attachment of amino acids by ribosomes.
___ tRNA (b) Structural component of ribosomes.
___ rRNA (c) Transcripts of protein-coding genes.
___ snRNA (d) Maturation of transcripts.
mRNA (c); tRNA (a); rRNA (b); snRNA (d)
RNA molecules are ____________________.
single-stranded
The rho protein is involved in which aspect of transcription?
termination
The DNA sequence of a gene is 3'-C C A T G C T A-5'. The corresponding sequence of the mRNA produced from this gene is ____________________.
5'-G G U A C G A U-3'
The DNA sequence where RNA polymerase binds at the beginning of transcription is called the ____________________.
promoter
The major product of transcription is a molecule of ____________________.
RNA
Transcription and translation are coupled in ____________________.
bacteria
Which of the following statements is true?
Not all transcribed genes are translated to protein.
Which is a characteristic of a rho-independent terminator?
hairpin loop followed by a string of U's
Which is the best representation of the central dogma, as proposed by Francis Crick in 1956?
DNA RNA protein
Which of the following is NOT a way in which RNA differs from DNA?
RNA has nitrogenous bases bonded with the 1' carbon.
-nitrogenous bases covalently bonded to the 1' carbon, is the only feature listed that is shared with DNA.
Which of the following is not required for initiation of transcription?
primer RNA sequence
Which subunit of the RNA polymerase holoenzyme is essential for recognition of the two consensus sequences in an E. coli promoter?
s factor
Which type of RNA is involved in the splicing of pre-mRNA molecules in eukaryotic cells?
snRNA
-Snurps (snRNAs) are involved in the removal of introns from mRNA transcripts prior to translation.
There are two main forms of ß-thalassemia: ß-plus and beta-zero. ß-plus thalassemia occurs when a reduced amount of ß-globin protein is produced, while ß-zero thalassemia occurs when no ß-globin protein is produced. Which of the following mutations is most likely to result in the appearance of ß-zero thalassemia in an individual?
A single base-substitution mutation in the 5' splice site of Intron 1.
Suppose there is a single base-substitution mutation in the poly(A) tail addition site of the ß-globin gene. Assuming that this mutation has an affect on transcription, what is the most likely result of the mutation?
The reduction of ß-globin protein due to a reduction in the stability of the mRNA.
In the intron, a mutation at the 5' splice site affects the binding of which small nuclear ribonucleoprotein particle? (You must look in the "RNA Splicing Process Book" in the exercise for the answer)
U1
A mutation in the branch-point adenine affects the binding of which small nuclear ribonucleoprotein particle? (You must look in the "RNA Splicing Process Book" in the exercise for the answer)
U2
Which of the following best describes the reason why a base-substitution mutation in an intron of the ß-globin gene can result in ß-thalassemia?
The mutation affects RNA splicing, which results in a defective ß-globin protein.
During the initiation step of transcription, what molecule binds the promoter region of a DNA molecule?
RNA polymerase
During transcription, the synthesis of the mRNA strand proceeds in which direction?
5' to 3' only
Which type of RNA is found only in eukaryotes?
snRNA
What happens during the elongation step of transcription?
An RNA transcript if formed and then drops off the DNA template
Prokaryotic transcription begins when RNA polymerase binds to which site of the gene region?
-35
Which event occurs at the termination of transcription?
-RNA synthesis stops.
-The RNA chain is released from the DNA.
-RNA polymerase is released from the DNA.
-ALL OF THESE
Which of the following is not found in a eukaryotic promoter?
-10 box
In eukaryotes, where does transcription take place?
In the nucleus
In eukaryotes, precursor mRNA molecules are processed in the
nucleus
The single strand of mRNA that is produced during transcription has the same polarity as the _______ strand of DNA.
nontemplate
The sigma factor of RNA polymerase is necessary for
specific recognition of promoter elements.
A prokaryotic mRNA transcript
-is ready to be translated as soon as it is transcribed.
-undergoes coupling of transcription and translation.
-BOTH
Which parts of a eukaryotic gene are transcribed?
Both exons and introns
In eukaryotes, the initiation complex binds DNA at the
TATA box.
The process by which genetic information is transferred from DNA to RNA is called
transcription
During the initiation step of transcription, what molecule binds the promoter region of a DNA molecule?
RNA polymerase
Prokaryotic transcription begins when RNA polymerase binds to which site of the gene region?
+1
The sigma factor of RNA polymerase is necessary for
specific recognition of promoter elements.
Molecules of tRNA are
-75 to 90 nucleotides in length.
-single-stranded with secondary structure.
-cloverleaf in shape.
-synthesized with modified bases.
-ALL OF ABOVE
The function of a ribosome is
to hold mRNA and tRNAs in the correct positions to enable translation.
Which of the following is a characteristic of a rho-dependent terminator?
Termination requires ATP
Which of the following is the correct statement.
A promoter is a noncoding regulatory part of a gene.
Which of the following are correct statements.
None of the above are correct
-In Eukaryotes, mature mRNAs typically have introns, a 5' cap, and a polyA tail.
-Before a prokaryotic mRNA can be translated, t must be modified by the addition of a polyA tail.
-Histone proteins play a critical role in RNA splicing
Prokaryotic mRNA
is polycistronic
During transcription, RNA polymerase joins nucleotides
from 5' to 3'.
The consensus sequence for the -35 box of an E. coli promoter is 5'-T T G A C A-3'. This sequence functions to
bind RNA polymerase holoenzyme containing a specific sigma factor.
The DNA sequence where RNA polymerase binds at the beginning of transcription is called the
promoter
Which of the following statements is true?
Not all transcribed genes are translated to protein.
Which of the following is NOT required for initiation of transcription?
primer RNA sequence
Which subunit of the RNA polymerase holoenzyme is essential for recognition of the two consensus sequences in an E. coli promoter?
s factor
Which type of RNA is involved in the splicing of pre-mRNA molecules in eukaryotic cells?
snRNA
Which type of RNA polymerase sigma factor predominates during the heat shock response?
s32
The isolation of temperature-sensitive mutants has been a common tool of molecular genetics. TS-mutants make proteins that function normally at lower temperature but cannot function at higher temperatures. A TS-mutant of a mouse was recently isolated that had a curious property: at the higher temperature, almost all of the transfer RNA was missing from cells. You hypothesize that this is a TS-mutant in an RNA polymerase. How would you verify your hypothesis?
Determine whether RNA polymerase III activity decreases as temperature increases in the TS-mutant.
Working in a coroner's office, you are investigating the mysterious death of a person found in a wooded area in the spring of the year. During a cellular analysis of this body, you learn that the levels of mRNA that can be obtained from critical tissues are very low, and you find mushrooms in the contents of the stomach. After examination of the mushrooms, you learn that they are a species of Aminita, and a search of the Internet reveals that a toxin in this fungus inhibits RNA polymerase. However, this isn't very specific information. To be more certain of the cause of death in this case ,you would need to verify that alpha-aminitin inhibits which eukaryotic RNA polymerase?
RNA polymerase II
In eukaryotes, transcription is initiated by the formation of a preinitiation complex of transcription factors and RNA polymerase at the TATA box of the promoter. Give the correct order of the steps below.
(a) The TFIID complex containing the TATA box binding proteins binds to the TATA box.
(b) TFIIA and TFII B bind to the initiation complex.
(c) RNA polymerase begins transcribing the sense strand of the DNA producing a complementary RNA.
(d) TFIIE and TRIIH bind to the complex, and the helicase function of TRIIH produces a small bubble in the double-stranded DNA.
(e)TFIIF binds to RNA polymerase, and this complex adds to the complex assembling at the TATA box
(a) > (b) > (e) > (d) > (c)
In the maize alcohol dehydrogenase gene, there are sequences found in the 5'-untranslated region, the first 26 codons of the protein-coding region, and in the 3'-untranslated regions of the gene that are responsible for determining that this gene is transcribed only during anaerobic conditions and for determining how many copies of the mRNA for this gene are made per cell. These sequences would be considered __________.
Enhancer sequences
The addition of 7-methyl guanosine to the 5' end of a pre-mRNA during translation by a 5' to 5' linkage is referred to as capping. What would you expect to be the phenotype of a mutation in the capping enzyme that adds the 5' cap?
The 5' cap remains throughout processing of the pre-mRNA and is present in the mature mRNA, protecting it against degradation by exonucleases; and the 5' cap is important for the binding of the mRNA to the ribosome as an initial step of translation.
Which of the nucleotides found in a completed mRNA were NOT transcribed from the DNA sequence coding for the gene?
the A nucleotides in the poly (A) tail
Which of the following steps is responsible for the production of an active spliceosome during the splicing of introns?
Dissociation of the U4 snRNP from the spliceosome complex is the activating step leading to removal of the intron, the formation of a "lariat," and an mRNA with the intron spliced out.
A series of three mutants in the CAM5 gene of Arabidopsis thaliana were recently isolated. Examination of the molecular properties of these three mutants revealed the following: in mutant cam5-1,a piece of extra DNA was inserted into the CAM5 gene DNA 3 nucleotides before the single intron in this gene; in the cam5-2 gene, the extra piece of DNA was inserted between the G and U at the 5' splice junction of the intron; and in the cam5-3 gene, the extra piece of DNA was inserted in the middle of the intron at least 20 nucleotides away from both the splice junctions and the upstream branching sequence. Based on what you know about intron splicing, predict which of these mutants might produce a completely normal CAM5 mRNA.
cam5-3
A polysome contains ____________________.
-mRNA
-tRNA
-rRNA
-ALL OF ABOVE
A sequence of 3 bases in DNA has the sequence CGT. What is the corresponding tRNA anticodon for this sequence?
CGU
A tRNA molecule carries the anticodon UGC. What is the corresponding codon in mRNA?
GCA
Before any kind of post-translational processing occurs, all polypeptides begin with the amino acid ____________________.
methionine
In eukaryotes, some protein are synthesized on the ___________ and modified in the ____________________.
endoplasmic reticulum; Golgi complex.
How long, in amino acids, would be a polypeptide produced in the translation of a 24-base mRNA molecule?
7
In prokaryotes, the upstream mRNA sequence required for the initiation of protein synthesis is the ___ sequence.
Shine-Dalgarno
In the genetic code, the codon ___ is a stop codon.
UAA
In the genetic code, the codon that signifies the start of translation is ____________________.
AUG
In the genetic code, the codon UAG signifies which amino acid?
none...stop codon
Proteins are constructed from which molecular "building block?"
amino acids
Given there are 20 amino acids and 4 nucleotides, what is the minimum size the genetic code can be?
3-base codons
The genetic code is ____________________.
triplet
The sequence of amino acids in a polypeptide chain determines the protein's ___ structure, while the number of polypeptide subunits determines its ______ structure.
primary; quaternary
What type of covalent bond joins the molecular building blocks in a protein?
peptide bond
Which best represents the events that occur during translation?
mRNA ---> protein
The genetic code is redundant in that more than one codon often specifies the same amino acid. The codons for a given amino acid typically vary ____________________.
in the third codon position
Which event occurs at the beginning of translation?
mRNA binds to a ribosome.
The longevity of a eukaryotic mRNA molecule is dependent on its ____________________.
Polyadenylation (poly-A "tail")
Which type of nucleic acid is a structural component of ribosomes?
rRNA
-Only ribosomal RNA is an actual component of ribosomes. Transfer RNA is only transiently associated with a ribosome during the elongation phase of translation
Which of the following is a characteristic of protein?
-High molecular weight
-Contains nitrogen
-BOTH
What makes up the initiation complex at the start of translation?
The small ribosomal subunit, an mRNA molecule, and an initiator tRNA molecule
What is the function of a ribosome?
To hold mRNA and tRNAs in the correct positions to enable translation
What is the basic shape of a tRNA molecule?
A three-dimensional cloverleaf
What is the role of tRNA in translation?
It binds to an mRNA codon and carries the corresponding amino acid.
Why is it that a carrot plant can express a bacterial gene?
Because the genetic code is the same in both organisms
In the genetic code, both AAU and AAC code for asparagine. For this reason the code is said to be
degenerate
In a gene sequence, the DNA codon for tryptophan experiences a mutation at the first base position, changing it to T. What will be the resulting amino acid?
Arginine
A mutation causes a G to be inserted after the first base of the codon for tryptophan. How will this affect the growing polypeptide chain?
The reading frame will be shifted to the left, and the wrong amino acids will be added from this point on.
Ribozymes in the large ribosomal subunit catalyze peptidyl transferase activity during elongation. What is the immediate result?
The bond is broken between the tRNA at the P site and its amino acid, and a peptide bond is formed between this amino acid and the one attached to the tRNA in the A site.
What signals the termination of translation?
The ribosome reaches a stop codon.
A peptide bond forms between the ______ of one amino acid and the ______ of another.
amino group, carboxyl group
The majority of naturally occurring amino acids are
neutral and nonpolar
An alpha helix and a beta-pleated sheet are types of
protein secondary structure
The concept that a set of three nucleotides specifies a particular amino acid provides the basis for
the genetic code
In eukaryotes, the AUG initiation codon is located in the _______ sequence.
Kozak
How many naturally occurring amino acids are used by ribosomes to construct proteins?
20
Which enzyme "charges" a tRNA molecule with the appropriate amino acid?
Aminoacyl-tRNA synthetase
Which of the following statements is correct?
For every codon, there is one amino acid.
Jack is blood type A, and Jill is Blood type B. Their fist child is blood type O. This means that
Jill has an enzyme that places galactose on her red blood cell antigens.
Jack is blood type A, and Jill is Blood type B. Their fist child is blood type O. This means that
Both Jack and Jill are heterozygous.
DNA polymerase catalyzes the formation of a phosphodiester bond between a
5' phosphate and a 3' hydroxyl group.
During synthesis, all DNA polymerases add nucleotides in which direction?
from 5' to 3'
In bacteria such as E. coli, replication of the chromosome is
semidiscontinuous and bidirectional
In eukaryotes, DNA replication occurs during which phase of the cell cycle?
S
Why, exactly, is a primer necessary to initiate DNA synthesis?
A free 3'-OH group is necessary for DNA polymerase.
The 3' to 5' exonuclease activity associated with DNA polymerase reduces the frequency of replication errors to
1/1,000,000,000
The sequence of nucleotides in one strand of DNA is 5' - C C A C T G G - 3' What is the sequence of the complementary strand of DNA?
3' - G G T G A C C - 5'
Under a hypothesis of semiconservative DNA replication, Meselson and Stahl expected to see _____ DNA band(s) in the cesium chloride gradient after one round of replication, and _____ band(s) after two rounds of replication.
1; 2
Identify the order in which the following enzymes play a role in DNA replication:
helicase, primase, DNA polymerase, ligase
When the DNA double helix is replicated, the newly synthesized 5' to 3' continuous strand is considered the ___ strand.
leading
Which E. coli DNA polymerase has the ability to "proofread" newly synthesized DNA and remove erroneous bases?
DNA polymerase I and III
What is the difference between a primer and a template?
-A template is always DNA, whereas a primer can be DNA or RNA.
-A template is always copied by DNA polymerase, whereas a primer never is.
-A primer but not a template must have a free 3' hydroxyl group.
-ALL OF ABOVE
Which of the following is NOT required for DNA synthesis reactions?
calcium ions
Place the following steps in correct order leading to the formation of a replication bubble at a replicator sequence in the E. coli chromosome.
(a) DNA helicases bind to the 13-bp repeat region and untwist the DNA double helix.
(b) DNA primase binds to single-strand regions of the replicator sequence, and RNA primers are made.
(c) Initiator proteins encoded by the dnaA gene bind to the 9-bp repeats.
(d) On the leading strand, DNA polymerase III binds and begins continuously replicating DNA toward the replication fork.
(c) > (a) > (b) > (d)
Choose the correct sequence of events occurring on the lagging strand at a replication fork in a bacterial replication bubble:
(a) DNA polymerase I, using 3' to 5'nuclease activity, removes the RNA primer and fills the gap with complementary DNA nucleotides.
(b) DNA ligase joins the completed DNA Okazaki fragments together, forming a completed new strand of DNA.
(c) Primase moves on the lagging strand toward the replication fork and makes a new RNA primer.
(d) DNA polymerase III binds at the primer and replicates the lagging strand back to a previously made RNA primer.
(c) > (d) > (a) > (b)
Based on the rates of DNA replication at each replication fork in the single replication bubble formed, it takes approximately 42 minutes to replicate the E. coli genome. Yet on enriched media, E. coli cells can demonstrate doubling times of only 20 minutes. How is it possible to make two new cells from one in 20 minutes if it takes 42 minutes to replicate the entire genome?
A new round of DNA replication is initiated each cell doubling. This means that when cells are doubling faster than the time it takes to replicate the genome, these cells contain chromosomes that are already beginning a second round of replication before the doubling occurs.
Suppose a new organism were just discovered that contains a very unusual DNA polymerase never before seen in any living thing. This DNA polymerase does not require an RNA primer, and it synthesizes DNA from 3' to 5' rather than the usual 5' to 3'. Which enzymes required for replicating the chromosome of E. coli would not be required in this new organism if the organism also had all the conventional bacterial DNA polymerases, unless otherwise stated in the answer?
primase, DNA ligase, and DNA polymerase I
In eukaryotes, during S-phase of the cell cycle, the DNA of all chromosomes is replicated using mechanisms relatively similar to those of bacteria. What in addition to the new DNA strands must be made during S-phase to permit the synthesis of the new sister chromatids?
two new strands of DNA for each chromosome, and enough histone 2A, 2B, 3, and 4 to double the number of nucleosomes that existed before replication
Nonsense mutation
A mutation that changes a codon from one that represents an amino acid to one that signals a chain termination
Missense mutation
A mutation that changes a codon from one amino acid to another
Frameshift mutation
A mutation that causes an addition or deletion of one or two base pairs in a gene
Point mutation
A mutation that causes a change in a single base pair
Neutral mutation
A mutation in a gene that causes no detectable change in the protein product
Which of the following nucleotide changes leads to a transition mutation?
Adenine to guanine
Which of the following is not mutagenic?
AZT
Base analogs may cause mutations because
they may exist in alternate chemical states that pair with different DNA bases than the normal state during replication.
The deamination of cytosine creates
uracil
Thymine dimers are commonly caused by
ultraviolet radiation
Xeroderma pigmentosum is a human genetic disease caused by
defective DNA excision-repair mechanisms
Mutation frequency is the
number of a specific mutation in a defined population.
The codon 5'-AAA-3' codes for the amino acid lysine. Which of the following mutations in this codon is a neutral mutation?
5'-AGA-3' to arginine
Spontaneous mutation rates are greatly reduced by
DNA repair mechanisms
A mutation during DNA replication causes a G to be inserted after the first base of the codon for tryptophan. How will this affect the growing polypeptide chain?
The reading frame will be shifted to the left, and the wrong amino acids will be added from this point on.
In Drosophila, the wild-type eye color is red. A mutation, vermilion, causes vermilion-colored eyes, unless there is a mutation in another gene, suv, which, when homozygous or hemizygous, results in eyes that are the wild-type red even in the presence of the vermilion mutation. This is an example of
intergenic suppression
A transposon is
-a DNA segment that can insert itself at one or more sites in a genome.
-a "jumping gene."
-a DNA segment that may cause mutations in genes or chromosomal rearrangements
-a mobile genetic element that may or may not leave a copy of itself in its original site when it moves to a new site
-ALL OF THESE
Nonsense suppressors are usually mutations in genes coding for
tRNa
Which of the following transposable elements are found in eukaryotes but not in prokaryotes?
-Families of autonomous and nonautonomous elements
-Retrotransposons
-Ty elements
In order for the dissociation element (Ds) mutations in corn to be stable,
an Ac element must not be present.
An IS (insertion sequence) element contains
a transposase gene and inverted repeats at the ends.
What is conservative transposition?
Movement of transposable elements without replication of the element.
Dissociation elements (Ds) in plants are examples of
-nonautonomous elements that require activation by an autonomous element.
-mutator genes that increase the spontaneous mutation frequencies of other genes.
-BOTH
Which procedure would you use to detect a nutritional mutation in microorganisms?
Replica plating
Genetic manipulation in Drosophila may be assisted by the use of
P elements.
Choose the best answer.
LINEs and SINEs are repetitive sequences in humans that can also, as retrotransposons, insert into genes and cause disease.
Choose the best answer.
-5-bromouracil (5BU) is a mutagen because it is an analog of the base thymine and may pair with guanine instead of adenine if it is incorporated into a DNA strand.
-A tautomer is an uncommon form of DNA base that naturally exists along with the common form.
-BOTH
The DNA polymerase proofreading mechanism maintains a low mutation rate
in prokaryotic genes.
5-bromouracil is an analog of which base?
thymine
A ___ mutation in a gene in amino acid biosynthesis pathway permits the bacterium to once again synthesize the amino acid.
reversion
A ___ mutation may result from the insertion or deletion of a nucleotide.
frameshift
Photolyase functions in
thymine dimer repair.
A mutation changes a codon for leucine into one that specifies isoleucine. This is a ___ mutation.
missense
A mutation changes an A-T base pair to T-A. This is a ___ mutation
transversion
A mutation occurs in which an AAA codon, which signifies lysine, into AGA, which signifies a chemically similar amino acid, arginine, and has no effect on protein function. This is an example of a ___ mutation.
neutral
A mutation occurs in which an AUU codon is changed to an AUC codon. Both of these codons signify the amino acid leucine. This is a ___ mutation.
silent
During replication, proofreading of the newly synthesized DNA is performed by
DNA polymerase
Ethidium bromide is a(n) ___ agent.
intercalating
In E. coli, suppressor mutations are often located in genes for
tRNA genes.
In an Ames test of an unevaluated chemical, numerous bacterial colonies grow on the minimal medium plates. Which of the following conclusions is valid?
The test chemical is mutagenic.
Nitrous acid induces ___ of bases in DNA.
deamination
The deamination of ___ produces mismatched thymines in DNA.
5-methylcytosine
The mutation induced most commonly in DNA treated with ultraviolet light is the result of
creation of thymine dimers.
In the absence of repair mechanisms, DNA mutates considerably from spontaneous and induced sources. This mutation rate is evident from people afflicted with compromised repair mechanisms, who suffer from
Xeroderma pigmentosum.
The sequence 5'-AUGGGGUGCCAUUUU-3' yields a polypeptide five amino acids long. What base substitution would truncate the polypeptide to only two amino acids?
changing the first cytosine to an adenine
Which of the following is an example of a nonsense mutation?
UAC to UAG
Which strain of bacteria is used in the Ames test for chemical mutagenicity?
Salmonella typhimurium
Which of the following mutations potentially has the greatest effect on gene expression?
a mutation in the promoter
Restriction enzymes are produced by
bacteria
Restriction enzymes that cut between different nucleotide pairs on the complementary DNA strands produce fragments with ________ ends.
sticky
A plasmid used as a cloning vector in E. coli must have
-an ori sequence.
-a selectable marker
-unique restriction sites
-ALL OF ABOVE
Which of the following would be the best restriction site?
CATTAC
The sequencing method in which altered nucleotides cause termination of the DNA chain was developed by
Sanger
In addition to restriction enzymes, which enzyme is required to insert a fragment of DNA into a cloning vector?
DNA ligase
The first restriction enzyme to be purified from E. coli RY13 is
EcoR1
The recognition sequences for many restriction enzymes are
palindromic
In a ________ blot, RNA fragments are separated in a gel and transferred to a support membrane.
Northern
A YAC cloning vector should have which of the following features?
-an ARS sequence
-a yeast telomere at each end
-a selectable marker
-unique restriction sites
-ALL OF ABOVE
The DNA fragment of which size would travel the least distance through an agarose gel?
the largest molecular weight
Which polymerase is used in the polymerase chain reaction?
Taq polymerase
Which piece of equipment is a necessity for a lab that wants to perform PCR?
thermal cycler
Which enzyme is required to make a cDNA library?
-DNA polymerase
-reverse transcriptase
-DNA ligase
-ALL OF ABOVE
When a 6 kb plasmid is cut with the restriction enzyme Hha1 and electrophoresed through an agarose gel, one stained band is observed. This indicates that there is(are. ________ restriction sites for this enzyme on the plasmid.
-1
(bc the plasmid is round, one band=one linear piece)
Choose the correct answer.

A. A DNA copy of an mRNA molecule is called complementary DNA or cDNA.
B. RT-PCR is a PCR technique used in amplifying DNA copies of mRNA
C. All of the above are
D. None of the above are correct
All of Above
When DNA is cut with a restriction enzyme, the resulting fragments have
-a 5' phosphate
-a 3' hydroxyl
-BOTH
Bacteria protect their own DNA from restriction enzyme damage by adding _______ groups to certain nucleotides.
methyl groups
A polylinker region or multiple cloning site in a cloning plasmid is characterized by
multiple restriction cut sites.
Vectors capable of entering both prokaryotic and eukaryotic cells are
shuttle vectors
In DNA electrophoresis, fragment separation is based on
fragment size
The chemical "label" that permits visualization of DNA fragments in sequencing
machines is
fluorescent dyes
________ blots are used to study DNA fragments, while ________ blots are used to study RNA fragments.
Southern, northern
Many bacteria are naturally capable of taking up endogenous fragments of DNA in their environment, a phenomenon termed
transformation
A serious problem encountered with artificial chromosomes like YACs is
recombination within the host cell.
Which restriction enzyme leaves blunt ends?
SmaI
A restriction enzyme cuts DNA and leaves the following end: GGCTA
C
Which of the following could be the sequence of the corresponding end of the other fragment generated by the enzyme?
T
CGATA ?????
A(n) ___________ is basically a photograph using X-ray film, used in such genetics applications as identifying the position of radiolabeled molecules on a gel.
autoradiogram
Successful insertion of a DNA fragment into the polylinker region of pUC19 is detected by
absence of the enzyme ?-galactosidase.
Which type of cloning vector occurs in nature?
Plamids and bacteriophages
The plasmid pUC19 is useful for cloning because it has a
-multiple cloning site.
-ori sequence.
-ampR selectable marker.
-high copy number.
-ALL OF ABOVE
Which restriction enzyme leaves staggered ends in DNA?
EcoR1
Which enzyme is required to make a cDNA library?
-DNA polymerase
-DNA ligase
-reverse transcriptase
ALL OF ABOVE
A plasmid is treated with the restriction enzyme PstI. To facilitate cloning a fragment of DNA from a bacterial chromosome into this plasmid, the chromosomal DNA should be treated with
PstI
Restriction enzymes are so named
for their ability to restrict viral invasion of bacterial cells by cutting up DNA at specific "restriction" sites.
Bacteria that produce restriction enzymes protect their own DNA from attack by modifying it with
methylation
Dideoxynucleotides are used in which molecular biology technique?
Sanger sequencing
In which technique are DNA fragments physically separated primarily according to their size?
agarose gel electrophoresis
Of the sequences shown below, which would be the most likely target sequence for a restriction endonuclease?
CATATG
Plasmid DNA is treated with restriction enzyme A, and three bands are seen on an agarose gel following electrophoresis. This plasmid therefore has ___ restriction sites for enzyme A.
3
The best vector in which to clone a 1.2 kb fragment of DNA is a
plasmid
The probability of finding a restriction site for enzyme A, which has a six-nucleotide recognition sequence, on a molecule of DNA is
1/4,096
The Archaea are best known for the extremophiles, those cells that "love" extreme environments, such as very high temperature, high pressure, extreme pH, high metal ion concentration, and high salt. Members of the Archaea resemble Bacteria morphologically, occurring with shapes such as spheres, rods, and spirals. However, genome sequencing of a number of archaean genomes revealed some key differences. Which of the following is an INCORRECT statement about Archaea?
As in eukaryotes, there are introns in protein-coding genes and tRNA genes of Archaea.
Which plasmid of those listed below would be the best cloning vector?
pHA3: 1 restriction site for EcoR1, PstI, and BamH1; ori, tetR
YAC vectors are useful for cloning fragments of DNA that are in which size range?
200 - 2,000 kb
The whole-genome shotgun method has emerged as the most frequently used method for sequencing genomes. What is the correct order of the steps involved in whole-genome sequencing?
a - Separate DNA fragments by electrophoresis, and isolate fragments between 1600 and 2000 nucleotides in length.
b - Assemble the sequences from fragments into continuous sequences, ultimately generating the whole genome sequence.
c - Fragment the genomic DNA into small pieces using mechanical shear.
d - Make a clone fragment library of the genomic fragments.
e - Sequence the cloned fragments using efficient high-throughput robotic sequencers.
c > a > d > e > b
What is a transgene?
Artificially introduced DNA
What is an shRNA?
Transcript that has a stem and loop
Cy5 is a(n) _____________ used to detect DNA in a microarray experiment.
Fluorescent dye
What is HAR-1?
Small noncoding human RNA
Which of the following best describes BLAST?
BLAST searches for sequence matches in a nucleotide or prottein database.
Which of the following statements correctly describes reverse genetics?
A mutated gene is introduced into an organism to determine the phenotype.
The subfield of genomics that deals with gene expression and interaction is
functional genomics
RNA interference functions by
degrading the RNA complementary to the short, double-stranded RNA.
Which of the following triggers the RNAi pathway?
shRNA
Which of the following is not used in PCR amplification of DNA?
ddNTPs
Which of the following does not occur during PCR?
Synthesis of oligonucleotide primers
If you are setting up a PCR reaction, how much extension time per cycle should you allocate for the Taq DNA polymerase to amplify a 5-kb DNA fragment from a 10-kb template?
5 minutes
The drug ________ is added to mouse cell cultures to select against transformants that do not have the desired gene knockout.
ganciclovir
The Alu family is an example of
short interspersed repeat elements.
A transgene is a
gene introduced into an organism by artificial means.
The ________ gene is responsible for removing many of the drugs introduced into the human body.
CYP2D6
Which of the following is an archaean that has been identified in the human gut?
Methanobrevibacter smithii
Pharmacogenomics is the study of how
the genome affects responses to drugs.
The human-accelerated region 1 (HAR-1) gene
is a small, noncoding RNA expressed in the brain.
Linkage disequilibrium refers to a condition in which
a set of specific alleles of two or more genes tend to appear together.
A genomic region can rapidly become very common in a population due to
positive selection.
The representational oligonucleotide microarray analysis (ROMA) represents
a comparative genomics approach.
Metagenomic analysis involves
analyzing DNA from environmental samples.
A microbiome consists of
the transcriptome from a particular microorganism under different environments.
Choose the 1 best answer.

A. "Knockout" mutants have had the activities of certain genes eliminated, which can aid the researchers in determining the effects of those genes on physiology, development, and other functions.
B. Bioinformatics is a relatively new field that combines elements of genomics with computer science and mathematics.
C. The transcriptome is the complete set of polypeptides produced by an organism.
D. Both A and B are correct.
E. All of the above are correct
Both A and B
Choose the 1 best answer.

a. BLAST is a software that searches for similarities between DNA sequences only.

b. Both strands of the short, double-stranded regulatory RNA molecules are required by the Slicer protein in order to target the complementary RNA for degradation.

c. Sequence similarity between genes plays an important role in assigning gene function.

d. Both A and C are correct.

e. All of the above are correct
C. sequence....
Choose the 1 best answer.

A. Cy3 and Cy5 are radioactive tags used in microarrays.
B. The 16S rRNA gene from human gut microflora was amplified and sequenced to understand how the gut microbes are related. 33) ______
C. The genome of cancer cells tends to become unstable. 34) ______
D. Both B and C are correct.
E. All of the above are correct
Both B and C
What are the different methods by which we can assign function to particular genes?
-By searching for sequence homology with genes of other organisms whose functions are known.
-By interfering with the gene by making knockouts and studying the phenotypes produced..
-By interfering with the gene through gene silencing by RNA interference and studying the phenotypes produced..
ALL OF ABOVE
Imagine that you are using random PCR primers to amplify fragments of DNA. Would you expect to get more amplification products if you set the PCR machine at a higher or lower annealing temperature?
Higher annealing temperatures increase "stringency," so fewer transcripts would be expected.
Which of the following steps is NOT involved in constructing a knockout mutant in yeast?
-A "deletion module" is constructed with a selectable marker (such as an antibiotic resistance gene).
-Transformants are selected using an antibiotic resistance gene.
-The module recombines with the target knockout gene
-Successful gene replacements can be confirmed with PCR.
-ALL OF ABOVE
Why are BLAST comparisons based on protein sequences often easier to interpret than those based on DNA sequences?
-DNA sequences often have greater mismatches because of the degeneracy of the genetic code.
-Protein matches involve 1 of 22 amino acids at each position while DNA only has 1 of 4 nucleotides possible.
-Three nucleotides are required to make a single amino acid, but changes in some positions can be meaningless.
-All OF ABOVE
Calculate the number of copies that would be produced from a single starting molecule after 10 rounds of PCR.
1024
Why are the number of proteins in the eukaryotic proteome so much greater than the number of eukaryotic genes?
-Eukaryotic translation is characterized by transcript processing, e.g. exons are differentially spliced to yield different polypeptide products.
-Many functional proteins have quaternary structure, the subunits of which are provided by different genes.
-BOTH
Why is the Taq DNA polymerase well-suited for PCR?
-Taq DNA polymerase is a heat-stable enzyme that was isolated from the bacterium Thermus aquaticus.
-It can maintain function and structure at very high temperatures
-PCR can run without having to inject a new enzyme after each heat denaturation cycle.
-ALL OF ABOVE
Why does the transcriptome differ within an organism's cell types?
-All the genes of a multicellular organism are not expressed in every cell type.
-The various cell types express different subsets of the genome,
-The makeup of the transcripts (the transcriptome) differs depending on which genes are expressed at a given time.
-ALL OF ABOVE
What is one advantage that an RNAi screen may have over a screen for gene knockouts?
-A screen for gene knockouts usually does not yield deletions of essential genes because they are nonviable and do not live.
-An RNAi screen, however, may often lead to a knockdown, rather than a knockout, of an essential gene, which may be viable.
-ALL OF ABOVE
How can we explain the fact that the human genome contains far fewer genes than was predicted would be necessary for our survival?
The microorganisms that reside within our bodies help us by synthesizing chemicals, like vitamins, that we then use.
What does a large haplotype block suggest about a genomic region?
-A large haplotype block usually indicates a recent origin, because the older a block, the greater the chances that it would have undergone genetic recombination at some point in the past.
-That some mutation within the haplotype block imparted a fitness advantage and has therefore been selected for (positive selection).
-BOTH
How do we know that some of the microbes in our gut are beneficial to us?
Individuals lacking normal intestinal microbes have defects in the function of the immune system and in wound healing
The first complete genome sequenced was that of
the human mitochondrion.
A genetic map shows
-the location of genes on chromosomes.
-the relative distance between genes on chromosomes.
-BOTH
Genetic distances associated with genetic maps are generally obtained
by an analysis of the frequency of recombination between genes.
_______ were the first class of genetic marker developed by geneticists.
RFLPs
RFLPs arise by
-base changes that add or delete restriction enzyme recognition sites.
-addition or deletion of bases between restriction enzyme recognition sites.
-BOTH
Which of the following sequences is considered an STR?
TACGTACGTACG
A SNP represents a change in
(none of the above)
they are single base pair deletions
Expressed sequence tags, or ESTs,
-are genetic markers generated from cDNA.
-pertain to expressed genes only
-oligonucleotides derived from mRNA.
-
Which of the following statements about genomes is false?
Most of the human genome consists of coding DNA
Announcement of the first draft sequence of the complete human genome was a monumental moment in the history of genetics. This announcement was made
February 2001.
The ________ method was used by the Celera Genomics corporation to sequence the human genome.
direct shotgun
In a clone-contig mapping experiment, four clones were obtained with the following STS markers:
Clone 1: O P G EClone 2: A C D MClone 3: X O PClone 4: D M N X O

The order of the markers in this part of the genome is:
A C D M N X O P G E
Candidate open reading frames of a genome are identified by searching for
a start codon "in frame" with a stop codon.
Which type of cloning vector is commonly used in the construction of contig maps?
-BACs
-YACs
In a sequenced genome, candidate protein-encoding genes are identified by searching for
ORFs
Which of the following restriction enzymes is most useful as a tool in genome sequencing?
NotI
The human genome contains approximately _________ genes.
20,000
The human genome consists of approximately _________ base pairs.
3.2 billion
Choose the 1 best answer.

A. The human genome consists mostly of noncoding DNA.
B. The distribution of coding genes is surprisingly even throughout the human genome.
C. Humans have 2N = 46 chromosomes, so the human genome consists of the sequence data of 23 chromosomes.
D. All of the above are corect.
E. None of the above are correct.
A
Choose the false statement.

A. The first eukaryote to have its genome completely sequenced is a fungus.
B. The "transcriptome" is the complete set of polypeptides produced by an organism.
C. Clone contigs are a set of contiguous, partially overlapping sequences that collectively cover a whole chromosome or chromosome region without gaps.
D. A relatively new field that combines elements of genomics with computer science and mathematics is called bioinformatics.
E. The NCBI website is an example of a bioinfomatic website.
B
Explain the basic differences in goal and approach of functional, structural, and comparative genomics.
Statement 1. _______________ considers physical and genetic mapping and sequencing
Statement 2. _______________ is the study of gene expression and interaction
Statement 3. _______________ involves making cross-species comparisons in genome structure and function.
St.1=Structural genomics : St.2=Functional genomics : St.3 = Compative Genomics
Choose the 1 best answer.

a. The mapping approach involves generating detailed (high-resolution) genetic and physical maps for each chromosome, and then sequencing each fragment of the map.

b. Shotgun sequencing involves cutting each chromosome into fragments and sequencing them, then assembling the complete sequence by identifying overlaps among the fragments.

c. All of the above are correct.

d. none of the above are corect.
C. All
If bacterial sequences in the human genome represent horizontal transfer, the transfer may have occurred in early humans, or in the more distant past, in primate ancestors of humans. In the latter scenario, modern humans inherited such sequences from a common ancestor. Which of the following is a way to test the hypothesis that bacterial sequences were vectored to humans vs. vectored to an ancestral primate?
-Check for the presence of identical sequences in other primates; if they are present, it is likely that transfer occurred early, and both humans and our primate relatives coinherited the genes from a common ancestor. If the sequences are unique to humans, transfer probably occurred later, in the human lineage only.
-Check even more distantly related mammalian lineages for the possibility that a very early transfer occurred, with the sequences retained in the human lineage but for some reason lost in the sister primate lineage.
-BOTH
Genetic distances associated with genetic maps are generally obtained
by an analysis of the frequency of recombination between genes.
The arrangement of the alleles for two genes, A and B, can be represented as (A B/a b). If crossing over does not occur, which gametes would result from meiosis?
-A B
-a b
-BOTH
Two genes, A and B, are located on the same chromosome. Which of the following represents the genotype of an individual who is heterozygous for both genes?
A b/a B
________ are a type of DNA marker used in genetic mapping.
-Restriction fragment length polymorphisms
-Variable number of tandem repeats
-Single tandem repeats
-Single nucleotide polymorphisms
-ALL OF ABOVE
RFLPs occur as a result of a mutation that causes
-the addition of a restriction site.
-the loss of bases between restriction sites.
-BOTH
The first type of DNA marker to be studied by geneticists was
RFLPs.
An STR consists of a repeated sequence containing ________ bases.
1 - 4
In the human genome, there are approximately ________ minisatellite sequence(s).
100
Which type of human polymorphism represents most of the known polymorphisms?
SNP
The short arm of a chromosome is called the ________ arm.
p
The physical location of the breast cancer gene BRCA1 in the human genome is 17q21. This means that this gene is located
on the long arm of chromosome 17.
Current technology limits the sequencing of DNA to fragments that are a maximum of ________ nucleotides long.
500
The ________ method was used by the Celera Genomics company to sequence the entire human genome.
direct shotgun
The first cellular organism to have its genome completely sequenced was
Haemophilus influenzae
The genomes of which of the following bacteria have been completely sequenced?
E. coli
The genome of which archeon genus was the first to be completely sequenced?
Methanococcus
The E. coli genome contains approximately ________ base pairs.
4,300,000
The ________ genome was the first eukaryotic genome to be completely sequenced.
Saccharomyces cerevisiae
The number of genes in the fruit fly genome is approximately ________ that of the yeast genome.
twice
In a sequenced genome, putative protein coding genes are identified by searching the sequence for
ORFs
FUN genes
-are found in yeast.
-have no known function
-belong in an orphan family
-ALL OF ABOVE
Knockout genes
-are functionally inactive.
-affect the phenotype of the organism
-BOTH
The complete set of mRNA transcripts in a cell is known as its
transcriptome
In a DNA microarray experiment, the probes are
-DNA molecules
-affixed to a glass chip
-unlabeled
-ALL OF ABOVE
The complete set of expressed proteins in a cell is its
proteome
A key issue being considered by the bioethics program known as ELSI is
-maintaining the privacy of genetic information
-the safe and effective introduction of genetic information in a clinical setting.
-the fair use of genetic information.
-professional and public education.
-ALL OF ABOVE
Once the entire human genome has been sequenced and annotated, it will be possible to determine if a person
-has a genetic disease.
-has the potential to develop a genetic disease.
-may develop a debilitating mental disorder.
-ALL OF ABOVE
The mRNA molecules produced from an active gene can be used as a template to synthesize
cDNA
A vector that contains a selectable marker gene, an origin of replication, a multiple cloning, and a Shine-Dalgarno sequence between a promoter and a terminator would likely be called a(n)
expression vector
A vector that is obtained as a linear molecule containing single T overhanging bases at each end and also contains a selectable marker gene and an origin of replication would likely be called a(n)
PCR cloning vector
Which of the following is NOT an advantage that bacteriophage vectors have over plasmid vectors?
They always contain multiple cloning sites with a greater number of restriction sites.
Which of the following statements about a Northern blot is INCORRECT?

a. In a Southern blot, DNA fragments are separated on the basis of size and blotted to a membrane filter; by contrast, in a Northern blot RNAs are separated on the basis of size and blotted to a membrane filter.

b. The size of the band on the membrane produced by the reaction of the probe with the mRNAs on the blot indicates the relative amount of mRNA in a cell to which the specific probe hybridizes.

c. The probes used to identify the mRNA of interest in a Northern blot must be made by PCR.

d. In each lane of a Northern blot, the mRNAs of different treatments to be compared are placed, but only a single probe is used to react with the entire blot. Thus, the results of one blot only relate information about a single gene.
C
Which of the following is a correct statement about polymerase chain reaction, or PCR?

a. Template DNA of known sequence that is bounded by two primers is amplified in a test tube using a special thermostable DNA polymerase. This technique is useful in a wide variety of molecular genetic strategies.

b. The DNA polymerase used in PCR is a special mutant form of E. coli DNA polymerase that is thermostable, and thus PCR can only be done on E. coli DNA.

c. A sequence can be amplified by PCR only after it has been inserted into a PCR vector, a requirement that greatly limits the utility of the technique.

d. It is critical that RNA be used as primers for PCR because DNA polymerases require RNA primers to initiate DNA synthesis, just as DNA polymerase does inside the cell.
A
Which of the following is NOT an application of PCR?
-ALL ARE
-amplifying DNA for cloning
-RT-PCR, or real-time PCR, for mRNA quantitation
-amplifying DNA for disease diagnosis, sex determination of embryos, or forensic analysis
Vectors capable of entering two or more different host organisms are known as
shuttle vectors
In a sequenced genome, candidate protein-encoding genes are identified by searching for
ORFs
Which technique is NOT a technique used to identify specific clones in a cDNA library?
-Immunoscreening using antibodies against a protein of interest.
-Using a heterologous probe for the gene of interest from a related species.
-BOTH
DNA markers are
DNA polymorphisms that are useful for genetic mapping.
A comparison of the sequence of a genomic clone versus a cDNA clone for a specific gene will demonstrate
-the 3'-UTR of the gene
-the 5'-UTR of the gene.
-the location of introns in the gene.
-ALL OF ABOVE
Total mRNA was prepared from wild type yeast cells growing on galactose as the sole carbon source. This
mRNA was then used to prepare a cDNA library in E.coli. The plasmid DNA was extracted from the E.coli cells containing
the library, and transformed into mutant gal1 yeast cells (unable to grow on galactose as the sole carbon source. Yeast
cells able to grow on galactose were selected, and the inserts in the plasmids born by such cells were examined.
In order for this experiment to work, the cDNA library must have been built in which type of vector?
a shuttle-expression vector
An STR is
Repetitive sequence used in DNA fingerprinting
In a yeast two-hybrid system, expression of the reporter gene indicates that
two proteins have interacted to produce a specific cellular outcome.
In the yeast Saccharomyces cerevisiae, the genes for galactose metabolism are ___ in the presence of glucose.
not transcribed at all
Which of the following is a technique used to generate copies of a DNA fragment?
PCR
Different DNA fragments generated by restriction enzymes are called:
RFLPs
Which of the following techniques is best suited to study protein interactions?
The yeast two-hybrid system
In yeast, expression of the GAL genes is induced when there is ________ in the culture medium.
galactose
When yeast cells are cultured in the presence of both glucose and galactose, the GAL genes are
neither transcribed nor translated.
For the yeast galactose metabolizing gene, GAL1, to be transcribed, the regulatory protein produced by the GAL4 gene binds to
upstream activator sequence G (UASG) region.
Successful cotransformation in the yeast two-hybrid system will result in the binding of proteins produced by each yeast expression vector. These fusion proteins function by
binding to the lacZ upstream activator sequence, enabling transcription.
Which of the following CANNOT be used to quantitate gene expression?
an expression vector
Using PCR to change a single base in a cDNA sequence is called:
site-directed mutagenesis
Allele-specific oligonucleotide hybridization tests determine whether an individual is ___ at the disease gene locus.
All of the listed responses are correct.
For which disease is there a molecular test that detects the mutation(s) associated with the disease?
There are molecular tests available for all of these diseases.
Foreign genes can be inserted into plant cells using a ___ vector.
Ti
Which of the following is an ecological danger of engineering herbicide-resistant crop varieties?
the possibility of subsequent transfer of resistance genes to related pest species by hybridization or horizontal transfer
In a capital crime, the DNA fingerprint from blood left at the scene is compared with that of the victim and three suspects. The lane containing the DNA from the crime scene blood showed three bands, whereas that of the victim and suspect 1 and 2 had two bands. The third suspect's DNA fingerprint consisted of a single band. From this information, it is possible to determine that the blood at the crime scene was left there by
NONE
In a paternity case, the DNA of a baby is compared to that of the two men that the baby's mother claims could be the father of her child. The mother's DNA fingerprint consists of a single band approximately 8,000 bp in size. The baby's DNA fingerprint consists of two bands that are 4,000 and 8,000 bp. Putative father 1 shows two bands of 5,000 and 6,000 bp, whereas the DNA of putative father 2 contains two bands of 4,000 and 6,000 bp. Which man cannot be ruled out as the father of this baby?
Putative father 2 cannot be ruled out.
In the genetic disease sickle-cell anemia, the disease-causing mutation creates a(n) ___ that is used as a DNA marker for that disease.
RFLP
On which type of cell would somatic cell gene therapy be attempted?
lung cell
Genetic engineering of dicot plants is often accomplished with Ti plasmids, which come from
plant pathogenic bacteria.
The results of a molecular test for a genetic disease determines
whether or not mutations exist in disease related genes.
When a foreign gene is introduced to replace a mutant gene, the wild-type gene is ___ incorporated randomly into the genome.
rarely
Which of the following human drugs are produced using recombinant DNA techniques?
-ALL
-
Which of the following is an application of DNA typing?
A. testing foods for the presence of pathogenic bacteria
B. establishing genetic variability in populations
C. forensic analysis in crimes against wildlife
D. All of these are applications of DNA typing. **********
DNA fingerprinting, or profiling, makes use of
noncoding repetitive sequences of the genome.
DNA from a normal human individual is cut with the restriction enzyme DdeI, and the fragments separated by gel electrophoresis are transferred to a membrane filter. The filter is probed with the 5' end of a cloned beta-globin gene, and two fragments of 175 bp and 201 bp are observed. DNA from another individual analyzed in the same way gives one fragment of 376 bp. What technique described above was used to produce these results, and what do the results mean?
The Southern blot results described show that the second individual has sickle-cell anemia.
________ were the first class of DNA sequence polymorphisms discovered in the human genome.
VNTRs
Choose the correct answer.

A. Somatic cell gene therapy can result in a cure for a genetic disease in an individual as well as any progeny produced by the individual.
B. Humulin is insulin created by recombinant DNA technology.
C. DNase is used to treat hemophilia.
D. Both A and C are correct.
E. none of the above are correct
B
Haploid means:
One half of a complete set of chromosomes
Diploid means:
Two complete sets of chromosomes
Euploid means:
Possessing the correct number of chromosomes
Polyploid
Several complete sets of chromosomes
Aneuploid
Possessing too few or too many copies of a single chromosome
A monohybrid cross:
Always involves alleles of a single gene
Dihybrid cross
Always involves alleles of two genes
In a test cross:
One parent must be homozygous recessive.
Phenotype:
is the physical manifestation of a trait.
Genotype
is the genetic makeup of an organism.
A dominant allele
is the allele that is expressed in the heterozygote.
Recessive allele
is the allele that has to be homozygous to be expressed.
In lilies, white flowers (W) are dominant to purple flowers (w). If two plants that are heterozygous for flower color are mated, the genotypic ratio of the offspring would be
1:2:1
In a pea plant that is heterozygous for seed color, what proportion of gametes will carry the recessive allele?
1/2
In his experiments, Mendel noted that when two traits are involved in a genetic cross, they are inherited independently of each other. The reason for this is that
genes on different chromosomes separate during the formation of gametes.
Which of the following genotypes would not usually be represented in a gamete?
AA
(same alleles)
The chi-squared statistic can best be described as
the standardized deviation of observed data from expected data.
In the F2 generation, how many genotypic classes could be generated from a dihybrid cross of two heterozygotes in which the genes involved show complete dominance?
9
In peas, tall plants are dominant to short plants. A cross between a tall pea plant and a short pea plant results in half the progeny being tall, and the other half being short. Therefore, the tall parent plant is genotypically
heterozygous
If the results of a chi-square test of a given set of data show a P value greater than 0.05, then the null hypothesis
cannot be rejected.
A P value in statistics is
the probability of getting the observed data distribution by chance.
A man whose father expresses a recessive trait marries a woman whose brother expresses the same recessive trait. What is the likelihood that the newlyweds could have a child expressing the trait?
1/6
In humans, brown eye color (B) is dominant to blue eyes (b). A brown-eyed man marries a woman with brown eyes and they have three blue-eyed daughters. What are the genotypes of the man and the woman?
Bb and Bb
The probability that two parents with a family of four will have one girl and three boys is
1/4
A couple with three girls is expecting a fourth child. The probability that this child is also a girl is
1/2
Net or overall probabilities are obtained by multiplying separate independent probabilities. This is formally known as
the product rule.
Which of the following statements concerning the inheritance of a dominant trait is true?
Every affected person must have at least one affected parent.
A dihybrid cross yields 320 F2 offspring. How many are expected to resemble the homozygous recessive parental?
20
In his monohybrid crosses for seed color in peas, Mendel reported 6,022 yellow seeds and 2,001 green seeds. How many of each color class were expected?
6,017 yellow and 2,006 green
In holly, serrated leaves are dominant to smooth-edged leaves, and red berries are dominant to green berries. Two holly plants heterozygous for leaf edge shape and berry color are crossed together. Assuming that the two traits assort independently of one another, what proportion of the progeny will have smooth-edged leaves and green berries?
1/16
Choose the best answer.

a. A testcross with a heterozygous dominant individual will yield only heterozygous dominant offspring.

b. Two individuals can be phenotypically identical, yet have different genotypes for a given trait.

c. The genotypic F2 ratio expected in a dihybrid cross is 9:3:3:1.

d. Both A and B are correct.

e. all of the above are correct.
B
Choose the best answer.

a. The phenotype determines the genotype.

b. True-breeding individuals are produced by repeated backcrossing.

c. Recessive alleles are usually loss-of-function mutations.

d. Both B and C are correct.

e. all of the above are correct.
BOTH B and C
A human with XXY chromosome composition would:
have Klinefelter syndrome
An individual with XO chromosome composition would:
have Turner syndrome
An individual with XX chromosome composition would be:
be a mammalian female
A eukaryote with 2N+1 chromosome composition would be:
Aneuploid
A eukaryote with 3N chromosome composition would be:
Polyploid
A person with an XO genotype for the sex chromosomes would be phenotypically
female
Cells obtained from a Triplo-X woman would contain ________ Barr bodies.
2
In human males, genes on the X chromosome are
hemizygous
In butterflies, males are the ________ sex.
homogametic
The key gene in mammalian sex determination is
the testis-determining factor gene
A litter produced by a calico cat is not expected to include
calico male kittens.
A human male who undergoes a sex-change operation will be chromosomally
XY
The chromosome theory of inheritance states that
genes are located on chromosomes.
The spindle fibers attach to the centromere via a protein complex called
kinetochore.
Plants that produce separate male and female flowers are said to be
dioecious.
In an organism with 16 chromosomes per cell, how many DNA molecules are present in a cell undergoing anaphase of mitosis?
32
Synaptonemal complex forms during
zygonema.
Phenotypically, a female (XX) mouse embryo that was transformed with a small piece of a Y chromosome bearing the SRY gene would develop as
a male.
Which of the following is an example of genetic mosaicism?
Calico coat color in cats
Individuals with Turner syndrome are
aneuploid.
Which of the following organisms has a ZZ-ZW method of sex determination?
Monarch butterflies
The largest human autosome is chromosome ________ and the smallest is chromosome ________.
1, 21
Chromosomes with only one arm are known as
telocentric.
Red-green color blindness in humans is an X-linked recessive trait. What will the progeny ratios be if a carrier female is mated with a normal male?
Half the sons will be color blind; half the daughters will be carriers.
Which of the following statements is not true?

A. Many plants exhibit alternation between haploid and diploid stages.
B. Chromosome number is generally constant within groups of organisms with common ancestry.
C. The Y-bearing sex is known as the heterogametic sex.
D. Sex determination is chromosomal in some organisms and genic in others.
E. The sex chromosome systems of birds and mammals are likely to have evolved independently.
B
Choose the 1 best answer.

A. A person with two X chromosomes is the homogametic sex.
B. A woman who is heterozygous for the hemophilia allele has a 100% chance of having an affected son.
C. Half a woman's somatic cells express her paternal X chromosome and half express her maternal X chromosome.
D. Both A and B are correct.
E. All of the abovve are correct.
A
Choose the best answer.

A. Synapsis usually forms between nonsister chromatids.
B. X-linked or sex-linked traits are expressed in males but not in females.
C. Barr bodies are inactivated X chromosomes.
D. Both A and C are correct.
E. All of the abovve are correct.
D. Both A and C
Choose the best answer.

A. In flowering plants, gametes are produced mitotically from spores.
B. The centrioles are highly conserved chromosome regions that interact with spindle fibers during cell division.
C. Some cells may exit the cell cycle and enter a nondividing G0 state.
D. Both A and C are correct.
E. All of the abovve are correct.
D. Both A and C
Historically, the most commonly occurring natural variant of a trait (usually dominant in expression) was termed ______ by geneticists.
wild type
The inactivation of X chromosomes in female mammals is one way that __________ is achieved.
dosage compensation
A woman who is heterozygous for a particular X-linked recessive trait marries a phenotypically normal man. What percentage of their sons will show the recessive phenotype?
50%
A woman who is heterozygous for a particular X-linked recessive trait marries a phenotypically normal man. What percentage of their daughters will show the recessive phenotype?
0
Dosage compensation of X-linked genes occurs in
-Humans
-Drosophila
-Caenorhabditis
-ALL OF THEM
Dosage compensation of X-linked genes occurs in
homozygous
Inactivation of an X chromosome in human females results from the process of ____________ and in the production of a _____________.
lyonization; Barr body
In Drosophila, females are the ___ sex.
homogametic
In humans, gender is determined by the presence or absence of which chromosome?
Y chromosome
In terms of the sex chromosomes, the gametes produced by a woman may contain
only one X chromosome.
A woman with triplo-X syndrome (47, XXX) is expected to have ______ Barr bodies in her cells.
2
Nondisjunction may involve which type of chromosome?
X chromosome, Y chromosome, or autosomes
Traits such as color-blindness that are carried on the X chromosome and expressed primarily in males are ___ traits.
-X-linked
-sex linked
-hemizygous
-ALL OF THESE
What is required for lyonization to occur in female somatic cells?
multiple copies of the X chromosome
Which of the following chromosomes is an autosome?
chromo 21
With respect to the sex chromosomes, the genotype of a person with Turner syndrome is
XO
If a trait is passed from a father only to his daughters and never to his sons, this trait is likely
a dominant sex-linked trait.
A trait that is passed only from fathers to sons and never to daughters would be an example of
a trait carried on the Y chromosome.
Crossing over occurs in which stage of meiosis?
prophase I
What do anaphase II of meiosis and anaphase of mitosis have in common?
Sister chromatids disjoin or separate.
When does the amount of DNA in a cell double during the cell cycle, and when does the number of chromosomes double?
DNA doubles during S-phase of the cell cycle, and the number of chromosomes doubles when the sister chromatids disjoin in anaphase.
A true-breeding strain (P1) of fruit flies has mahogany colored eyes and normal (wild-type) bristles. A second true-breeding strain (P2) of fruit flies has normal (wild-type) red eyes and stubble bristles. When they are crossed, the F1s are wild-type (red eyes and normal bristles). Those F1s are then crossed to flies that have both mahogany eyes and stubble bristles. The progeny of the F1s consist of 64 flies that have mahogany eyes and normal bristles, 76 flies that have red eyes and stubble bristles, 28 flies that have mahogany eyes and stubble bristles and 32 flies that are wild-type. Which of the following is a parental type?
Mahogany eyes and normal bristles
A true-breeding strain (P1) of fruit flies has mahogany colored eyes and normal (wild-type) bristles. A second true-breeding strain (P2) of fruit flies has normal (wild-type) red eyes and stubble bristles. When they are crossed, the F1s are wild-type (red eyes and normal bristles). Those F1s are then crossed to flies that have both mahogany eyes and stubble bristles. The progeny of the F1s consist of 64 flies that have mahogany eyes and normal bristles, 76 flies that have red eyes and stubble bristles, 28 flies that have mahogany eyes and stubble bristles and 32 flies that are wild-type. Which of the following is a recombinant type?
Wild-type red eyes and normal bristles.
A true-breeding strain (P1) of fruit flies has mahogany colored eyes and normal (wild-type) bristles. A second true-breeding strain (P2) of fruit flies has normal (wild-type) red eyes and stubble bristles. When they are crossed, the F1s are wild-type (red eyes and normal bristles). Those F1s are then crossed to flies that have both mahogany eyes and stubble bristles. The progeny of the F1s consist of 64 flies that have mahogany eyes and normal bristles, 76 flies that have red eyes and stubble bristles, 28 flies that have mahogany eyes and stubble bristles and 32 flies that are wild-type. Which of the following best describes a test Cross?
F1 to mahogany eyes and stubble bristles
A true-breeding strain (P1) of fruit flies has mahogany colored eyes and normal (wild-type) bristles. A second true-breeding strain (P2) of fruit flies has normal (wild-type) red eyes and stubble bristles. When they are crossed, the F1s are wild-type (red eyes and normal bristles). Those F1s are then crossed to flies that have both mahogany eyes and stubble bristles. The progeny of the F1s consist of 64 flies that have mahogany eyes and normal bristles, 76 flies that have red eyes and stubble bristles, 28 flies that have mahogany eyes and stubble bristles and 32 flies that are wild-type. Which of the following best describes gene linkage?
Genes that do not segregate independently
A true-breeding strain (P1) of fruit flies has mahogany colored eyes and normal (wild-type) bristles. A second true-breeding strain (P2) of fruit flies has normal (wild-type) red eyes and stubble bristles. When they are crossed, the F1s are wild-type (red eyes and normal bristles). Those F1s are then crossed to flies that have both mahogany eyes and stubble bristles. The progeny of the F1s consist of 64 flies that have mahogany eyes and normal bristles, 76 flies that have red eyes and stubble bristles, 28 flies that have mahogany eyes and stubble bristles and 32 flies that are wild-type. Which of the following describes a map unit?
Recombinants divided by the total × 100
If genes are linked and an F1 is testcrossed,
they produce more parental phenotypes than recombinant phenotypes.
Crossing-over is
the reciprocal exchange of homologous regions of chromatids.
Genes that are linked
do not assort independently during meiosis.
A chi-square analysis of linkage between genes k and f produces a P value of 0.99. What is the likelihood that these two genes are linked?
1%
If an AABB strain is mated with an aabb strain, an AB gamete produced by the resulting F1 is
parental.
During a dihybrid cross involving two linked genes, 18% of the resulting gametes showed a recombinant genotype. These two linked genes are ________ map units apart.
18
If two genes are not linked, then the expected phenotypic ratio resulting from a testcross is
1:1:1:1
In a species of Drosophila, genes q and r are found on the same chromosome 20 centimorgans apart. A cross was made between the following individuals:
q+_____r q_____r
X
q_____r+ q_____r

What proportion of the offspring would you expect to have the wild-type phenotype?
0.10
One map unit is equal to a recombination frequency of
1%
T. H. Morgan and his colleagues found that among the offspring of genetic crosses, parental phenotypic classes were the most frequent, while recombinant classes occurred less frequently. This observation led Morgan to conclude that
alleles of some genes assort together.
When does crossing-over occur?
Prophase I of meiosis
A DNA mutation that gives a distinguishable phenotype for a chromosome or gene is a
genetic marker.
The closer together two genes are on a chromosome,
the less likely there will be a recombination event between them.
In the offspring resulting from an F1 testcross, what percentage of recombinant phenotypes is expected if the genes under study are independently assorting?
50%
A two-point testcross is a cross between
a double heterozygote for two linked genes and a double recessive genotype.
How many phenotypic classes may be generated from a three-point testcross?
(2)3 = 8
Interference is a phenomenon in which
-BOTH
-the number of observed double crossovers is less than the number of expected double crossovers.
-the occurrence of one crossover interferes with the formation of another crossover nearby.
The following scenario applies to the questions below.
A testcross of trihybrid Drosophila produced the following phenotypes and number of offspring. A table showing phenotype and the number of offspring with each phenotype is below. A plus sign is used for wild-type phenotype; a letter indicates the mutant phenotype for that gene.
+++ 669
abc 653
++c 121
ab+ 139
+b+ 2280
a+c 2215
+bc 3
a++ 2
Without performing any calculations, which of the following is the gene order?
acb
The following scenario applies to the questions below.
A testcross of trihybrid Drosophila produced the following phenotypes and number of offspring. A table showing phenotype and the number of offspring with each phenotype is below. A plus sign is used for wild-type phenotype; a letter indicates the mutant phenotype for that gene.
+++ 669
abc 653
++c 121
ab+ 139
+b+ 2280
a+c 2215
b+bc 3
a++ 2
Which gene pair is closer together; i.e. there are fewer map units between them?
a ? b
The following scenario applies to the questions below.
A testcross of trihybrid Drosophila produced the following phenotypes and number of offspring. A table showing phenotype and the number of offspring with each phenotype is below. A plus sign is used for wild-type phenotype; a letter indicates the mutant phenotype for that gene.
+++ 669
abc 653
++c 121
ab+ 139
+b+ 2280
a+c 2215
+bc 3
a++ 2
The cross represented by a+b+c+/abc × abc/abc is
a three-point testcross.
choose the best answer.

a. Testcrosses may be used to determine if two genes are linked.

b. Two genes that are located far from each other on the same chromosome will show a higher frequency of recombination than two genes that are close together on the chromosome.

c. A linkage map illustrates the exact physical locations of genes on a chromosome.

d. Both A and B are correct.

e. All of the above are correct.
D. Both A and B
Choose the best answer.

a. Given three genes in order x y z, it is more accurate to measure the distance between x and z directly than to add up the shorter distances between x and y and y and z.

b. If in calculating the distance between two genes using data from a testcrossed dihybrid you arrive at a genetic distance of 70 map units, there is likely to be something wrong with your calculations, the experimental data, or with the experiment itself.

c. Genes may show 50% recombination either when the genes are on different chromosomes or when the genes are far apart on the same chromosome.

d. Both B and C are correct.

e. All of the above are correct.
D. Both B and C
Choose the best answer.

a. Parental strains are always homozygous dominant for all genes or homozygous recessive for all genes.

b. A coefficient of coincidence of zero is the same as an interference value of zero.

c. Statistical analysis of linkage between any two genes has 1 degree of freedom since there are only two classes of data, parental and recombinant.

d. Both B and C are correct.

e. All of the above are correct.
C
One map unit is equivalent to
one centiMorgan.
All of the progeny from a testcross were observed, and it was noted that out of a total of 500 progeny, 100 showed a particular recombinant phenotype. This indicates that the recombination frequency between the two genes involved is
20%
If you performed a test cross with respect to three linked genes (ABC/abc x abc/abc), found in the order A-B-C or C-B-A, the offspring genotypes expected to be least frequent are
AbC, aBc
For a given region of a chromosome, a coefficient of coincidence value of 1 indicates that
the expected crossover events occurred.
Genes that do not assort independently are
-ALL OF ABOVE
-linked
-on the same chromo
-synthetic
Genes that show 50% recombination in testcrosses are
unlinked (on separate chromosomes).
Physical markers are
phenotypic features of chromosomes that allow genotype to be distinguished.
In a two-point testcross, which of the following will lead to all recombinant chromatids?
four-strand double crossover
In his notes, Thomas Morgan indicated the genotype of a particular fruit fly as w+m+/Y. This indicates that
the eye color and wing form genes are on the X chromosome.
Under what circumstances might two linked genes appear to be unlinked?
The genes are very far apart on the chromosome.
In a three-point testcross, the predominant phenotypic classes of progeny are
parental types.
Two- and three-point crosses are
crosses made with respect to two and three genes, respectively.
In a three-point testcross, the gametes with the lowest frequency are
double-crossover recombinant gametes.
The recombination frequencies between three genes were determined. Genes k and a had a recombination frequency of 39%, while genes a and e had a recombination frequency of 26%. Genes k and e showed 50% recombination. What is the distance in map units between genes k and e?
65 mu
If you performed a test cross for three linked genes (ABC/abc x abc/abc) and there was no crossing over at all, how many offspring genotypic classes would you expect to see?
2
Three genes, larry, curly, and moe are on the same chromosomes. The recombination frequencies determined in crosses were larry-curly = 0.24 curly-moe = 0.16 larry-moe = 0.43 The order of the genes must be:
larry-curly-moe.
Two genes, A and B are located on the same chromosome, as illustrated in the following genotype:

A B

a b


The parental genotypes of this individual are
A B and a b
Mathematical formulae describing the relationship between recombination frequency and map distance are termed
mapping functions.
Which of the following best defines the distance signified by a map unit (mu)?
A recombination frequency of 1% between two genes.
For a coefficient of coincidence of 0.1, what is the interference value, and what percentage of expected double crossovers occurred?
0.9; 10%
Which of the following is used to define possible linkage between two loci in humans?
lod score
Assume that color and leg length in ogres are simple traits each controlled by a single gene. You cross a true-breeding wild-type green, long-legged ogre and a true-breeding brown, short-legged ogre. You then testcross the F1 green, long-legged ogres with brown, short-legged ogres. What is the recessive phenotype?
brown, short-legged ogres
A cross was performed between an organism with an AA BB genotype and one with an aa bb genotype. The F1 progeny were interbred. In the F2 generation, 400 of 2,000 progeny had the nonparental phenotypes. Which of the following statements is true?
The A and B genes show linkage.
Which of the following statements is correct?
a. Crossing over will never occur during mitosis because homologous chromosomes are never aligned.

b. Crossing over events may occur during mitosis, but they are very rare.

c. Crossing over commonly occurs during prophase of mitosis.

d. Crossing over does not occur in cells that do not undergo meiosis.
B
Tetrad analysis is used to map genes of organisms such as
the yeast Saccharomyces cerevisiae.
The hypothesis that a physical exchange of genetic material during meiosis can lead to recombinant phenotypes was first proposed by
Thomas Morgan.
Which of the following would be the gene product of a constitutive gene?
-ALL OF ABOVE
-DNA poly
-RNA poly
-ATP synthetase
In an inducible operon, the genes are
usually not expressed unless a signal turns them "on".
The regulatory substance that brings about gene expression in an inducible operon is called the
Inducer
In E. coli, the effector molecule that results in induction of the lac operon is
allolactose.
In the lac operon, the gene that encodes the ß-galactosidase enzyme is
lacZ
Which enzymes will be produced in a cell in which there is a nonsense mutation in the lacY gene?
ß-galactosidase
When the gene product of the lacI gene is present in bacterial cells grown in the presence of lactose
the genes in the lac operon will be transcribed.
In a cell with a lacOC mutation, the operon genes will
be expressed in the presence or absence of lactose.
A particular strain of E. coli is lacOC, lacZ+ and lac -. In the absence of lactose, which enzyme(s) will be produced in this cell?
ß-galactosidase only
In a lacI- strain of E. coli, the lac operon will be expressed
both in the presence or absence of lactose.
In a Plac- strain of E. coli growing in medium containing lactose, the bacteria
do not synthesize the enzymes necessary for lactose metabolism
The lac operon is
inducible and under both positive and negative control.
When allolactose binds to the repressor, a(n) ___ occurs which inactivates the repressor protein.
allosteric shift
The catabolite activator protein (CAP) binds to (the) ___ to regulate expression of the lac operon.
cyclic AMP
When cultures of E. coli are grown in the presence of lactose and glucose, the lac operon is under ___ control.
both positive and negative
Which of the following is a component of a bacterial operon?
-ALL OF ABOVE
-promoter
-operator
-structural genes
The TRP operon is under ___ control.
positive
The effector molecule for the TRP operon is
tryptophan
In bacteriophage lambda, the product of the cI gene is a(n)
repressor
In bacteriophage lambda, the lytic pathways are followed if the product of the ___ gene dominates.
cro
To identify the mutations in each a series of E. Coli strains, why is it necessary to examine both the haploid strains and the merozygotes for ß -galactosidase activity?
To determine which gene or regulatory element was mutated in each strain.
A strain containing the Oc mutation (I+Oc Z+) showed constitutive expression both by itself and as a merozygote of the form I +OcZ+/F'+O+Z+. Why?
-BOTH
-The mutation is cis-acting.
-The Oc mutation is dominant to O+.
A strain containing the Is mutation (Is O+ Z+) showed repressed expression both by itself and as a merozygote of the form Is O+Z+/F’ I+O+Z+. Why?
-BOTH
-The mutation is trans-acting.
-The Is mutation is dominant to I+
The lac operon is under
negative control.
The order of the structural genes in the lac operon is
5'-lacZ-lacY-lacA-3'
In the lac operon in E. coli, a nonsense mutation in the ________ gene will result in a loss of b-galactosidase activity in the cell.
lacZ
The inducer of the lac operon is
allolactose
Induction of the lac operon occurs when the repressor protein undergoes a(n.
mutation
To inhibit the transcription of operon genes, the lacI gene product binds to
the operator.
A lacOC mutation is
cis-dominant
During transcription of the trp operon, pairing of regions 2 and 3 in the leader peptide mRNA creates a(n. ________ signal.
antitermination
A mutation in which of the following locations would lead to constitutive expression of the lac genes?
-lacI
-lacO
-C or D
Which of the following mutations is dominant over wild-type lacI+ in a partial diploid experimental cell?
lacIS
How many structural genes are under the control of the trp operon promoter?
Five
In terms of regulation of gene expression, tryptophan and allolactose are examples of ________ molecules.
effector
Which of the following can be a transdominant mutation in partial diploid cells?
lacIS
The interaction between allolactose and the repressor protein results in a shape change known as a(n.
allosteric shift
Operons can best be defined as
a set of genes under common regulatory control.
The genetic switch for the infection pathways of lambda phage is controlled by two regulatory proteins, ________ and ________.
lambda repressor, Cro
Attenuation in trp gene regulation is accomplished by
formation of secondary mRNA structures in the leader region.
Choose the correct answer.

A. A constitutive gene is a gene that is expressed at all times.
B. A constitutive gene is not part of an operon.
C. Only prokaryotic organisms contain constitutively expressed genes.
D. Both 1 and 2 are correct
E. Both 1 and 3 are correct
A
Choose the correct answer.

A. Mutations of lac O<c> lead to attenuated expression lac structural genes.
B. lacI<s> encodes superrepressors, repressors that always bind to the operator and prevent gene transcription.
C. Both 1 and 2 are correct.!
D. Neither 1 nor 2 is correct!
B
If a gene must be physically contiguous with a second gene or the operon the second gene is in to regulate the expression of the second gene, we say that the first gene is:
cis dominant
Which protein is involved in positive regulation of the lac operon
the CAP protein
A population geneticist studies
-ALL
-genetic variation in natural populations.
-factors that cause genetic divergence.
-how biological characteristics influence the gene pool of a population.
5-methylcytosine is most often found associated with which DNA sequence?
CG
Genomes of eukaryotes contain many defunct or non-functional genes, generally rendered defective by mutations of their promoter regions. These are known as ____________________.
pseudogenes.
- Such non-functional genes are termed pseudogenes, and can provide clues to the evolution of gene families.
A hormone is a(n)
effector.
An enhancer element is ____________________.
a specific nucleotide sequence in DNA.
DNA that is bound to histone proteins ____________________.
cannot be transcribed.
DNase I hypersensitive regions are usually located ____________________.
upstream from the start site of transcription.
For a given gene, HREs (steroid hormone response elements) are located ____________________.
in an enhancer element.
Gene expression in eukaryotes is regulated at the level of ____________________.
-ALL OF ABOVE
-transcription
-processing
-translation
The mammalian immune system can produce billions of different antibodies. This tremendous gene product diversity is produced by ____________________.
exon shuffling.
In a eukaryotic cell, when a positive regulatory protein interacts with a promoter element ____________________.
transcription is activated.
mRNA-level control of gene expression can be accomplished by regulating ____________________.
-ALL OF ABOVE
-movement or transport of mRNA transcripts.
-translation rate of mRNA transcripts.
-longevity (degradation rate) of mRNA transcripts
In plant cells, gibberellin ____________________.
stimulates transcription.
In prokaryotes, gene regulation occurs primarily at the ___ level.
transcriptional
In the absence of galactose, the GAL genes are ____________________.
neither transcribed nor translated.
Peptide hormones bind _________, while steroid hormones bind ____________________.
with target cells in the cell membrane; with receptors in the cell nucleus.
The Gal4 protein in yeast interacts with DNA at a regulatory site upstream of the GAL genes. Its DNA binding domain is a(n)
zinc finger.
The motif of the DNA binding domains of most SHRs is usually a ____________________.
zinc finger.
Transcription factors and regulatory substances are generally ____________________.
DNA binding proteins.
Transcriptionally active genes have ___ level(s) of DNA methylation when compared to methylation of inactive genes.
lower
Transcriptionally active regions of DNA are ____________________.
sensitive to digestion with DNase I.
Steroid hormones
modulate gene expression in eukaryotes.
In eukaryotic cells, receptors for steroid hormones are found in the
-BOTH
-Cytoplasm
-Nucleus
What role does HSP90 play in the perception of steroid hormones?
HSP90 is a molecualr chaperone that holds the receptor in a conformation such that it can bind glucocorticoid.
The glucocorticoid receptor is activated when
it binds glucocorticoid and displaces HSP90.
In eukaryotic cells, steroid hormone response elements are found in the
enhancer regions of hormone regulated genes.
Once a pre mRNA has been produced, glucocorticoid receptor
returns to the cytoplasm, and binds to HSP90 to repeat the gene activation cycle.
Cells lacking a receptor for a particular steroid hormone
cannot respond to steroid hormones that they do not have receptors for.
To complete the synthesis of pre-mRNA in the nucleus, which of the following must take place?
-A 7-methyl-guanosine CAP must be added to the 5'-end of the transcript.
-A polyA tail must be added to the 3' end of the transcript.
The human calcitonin gene consists of _____ introns and ______ polyadenylation sites. This combination cause 2 different proteins to be made from this one gene.
4; 2
The post-transcriptional processing of RNA precursor molecules may be controlled by the choice of
-poly(A) site.
-intron splice site.
In the thyroid, a protein product called calcitonin is produced from intron 4. This is the result of
-ALL OF ABOVE
-exon 5 not being transcribed.
-exon 1 not be translated.
-posttranslational modifications that remove the polypeptide products of exons 2 & 3.
In neuronal cells in the brain, the calcitonin gene produces, calcitonin-gene-related protein (CGRP) from exon 5. The primary gene transcript consists of
exons 1, 2, 3, 4, and 5 plus all introns.
In neuronal cells, what is found in the mature mRNA that leaves the nucleus?
Exons 1, 2, 3, and 5 with all introns and exon 4 spliced out.
In neuronal cells
only exons 2, 3, & 5 are translated.
In both thyroid and brain
only exons 2 and e are translated in both tissues.
In both thyroid and brain
the final protein product is produced by posttranslational processing.
5-methylcytosine is most often found associated with
CG dinucleotides.
When a promoter element is bound by a positive regulatory protein, the result is
activation of transcription.
Unlike bacterial operons, eukaryotic operons
are exceedingly rare.
Hormones can be considered
transcription regulators.
Unlike prokaryotes, much gene regulation in eukaryotes
is controlled at the level of transcript processing.
Which of the following secondary structures may be a DNA-binding domain?
-ALL OF THEM
-zinc finger
-leucine zipper
-helix turn helix
Nucleosomes are
DNA-histone complexes.
The protein cofactor ubiquitin is involved in
degradation of proteins.
Chromosome-level gene repression involves
-ALL OF ABOVE
-supercoiling.
-physical blockage of gene regions
-chromatin formation.
-nucleosomes.
Change in the DNA-histone complex that increases transcriptional activity is termed
chromatin remodeling.
The protein class(es. involved in the activation of transcription is (are. :
-ALL OF THEM
-general transcription factors (GTFs.
-transactivators
-coactivators
Eukaryotic protein-coding genes contain both ________ elements and ________ elements.
-Both
-enhancer
-promoter
The influence of cell surface-binding hormones on gene expression is mediated by a process called
signal transduction.
The half-life of a protein is directly related to
its N-terminal amino acid residue.
Removal of the 5' G-cap of mRNA transcripts
leads to degradation by exonucleases.
mRNA regulation can be achieved at the level of
-ALL OF ABOVE
-transport
-processing
-translation
-life span degradation
mRNAs synthesized in oocytes that are destined for storage and later translation have ________ poly(A. tails.
shorter
Proteins that are encoded by the same gene but differ in structure and function are the product of alternative splicing in pre-mRNA processing. Such protein variants are termed
protein isoforms.
Heterochromatin is associated with
gene silencing
If a protein has a zinc finger, leucine zipper, or helix-turn-helix sequence, what is likely function of this protein?
It is a DNA-binding protein.
An enhancer element is
a specific nucleotide sequence in DNA.
DNA that is bound to histone proteins
cannot be transcribed.
Which of the following plays a role in chromatin remodeling?
histone acetyl transferases, histone deacetylases, and SWI/SNF
Posttranscriptional control of gene expression does NOT occur at which of the following levels?
gene silencing
mRNA-level control of gene expression can be accomplished by regulating
movement or transport of mRNA transcripts, translation rate of mRNA transcripts, and longevity (degradation rate) of mRNA transcripts
Which of the following statements about siRNAs and miRNAs is FALSE?

a. They are both approximately 22 nt long.

b. They are both incorporated into the RISC complex as ssRNA.

c. They are encoded by specific genes.

d. They both bind to the target mRNA by complementary base pairing.
C
Arrange the following enzymes involved in RNA interference by miRNAs into their correct order: (1) RNA polymerase II; (2) Dicer; (3) Ago1; (4) Drosha.
1-4-2-3
Polypeptide hormones bind _________, whereas steroid hormones bind _______________.
to cell surface receptors; with cytoplasmic receptors
The GAL4 protein in yeast interacts with DNA at a regulatory site upstream of the GAL genes. This regulatory site is called a(n)
upstream activating sequence (UAS).
miRNAs and siRNAs direct binding of the RISC complex to which region of an mRNA to effect posttranslational gene silencing?
the 3' UTR
Eukaryotic transcription factors and regulators are generally
DNA-binding proteins.
In a eukaryotic cell, when a positive regulatory protein interacts with a promoter element
transcription is activated.
Transcriptionally active genes have increased sensitivity in vitro to DNase I. DNase I-hypersensitive sites that are even more highly sensitive to DNase I are generally found at what position relative to a transcriptionally active gene?
the promoter region
A CDK is:
an enzyme that phosphorylate proteins important to the cell cycle.
Cyclins are:
Are made and degraded at specific points in the cell cycle
Oncogenes are:
Genes that produce abnormally active cell growth proteins
Proto-oncogenes are:
Normal growth-promoting genes
Tumor suppressors are:
Proteins that can stop the cell cycle
Hereditary retinoblastoma is an autosomal dominant hereditary cancer. Cells from retinal tumors in a child who has this disease possess
two non-functional copies of the retinoblastoma gene.
Apoptosis is
programmed cell death.
Protein kinases are enzymes that normally catalyze the
phosphorylation of cellular proteins.
A proto-oncogene that gains function due to amplification, translocation to a more transcriptionally active area of the genome, or a mutation that causes either an increase in function or the suppression of down-regulation, is
-BOTH
-dominant
-an oncogene
Metastatic cancer is
-BOTH
-malignant
-invasive
Retroviruses are responsible for which of the following conditions?
-ALL OF THEM
-AIDS
-Mouse Mammary tumors
-Rous sarcoma
Mutations in a normal growth-stimulating gene are most likely to have no effect or to cause
the loss of responsiveness to growth stimulation in the cell with the mutant gene.
Small DNA tumor viruses such as SV40 and HPV have viral oncogenes that are not homologs of host cell genes. Some of these novel viral oncogenes make proteins that exert their tumorigenic effect by
binding to and inactivating pRB.
________ play a pivotal role in programmed cell death.
Cyclins
In sporadic (nonhereditary) cancers, mutations occur in ________ cells.
somatic
Cancer is best defined as
uncontrolled and abnormal cell division.
Agents that can induce cancer through mutagenesis are called
carcinogens.
In retroviruses, the pol gene product is a(n)
reverse transcriptase.
v-onc genes are found in
cancer-causing retroviruses.
Malignant breast, colon, and lung cancers typically have
-ALL OF THESE
-
Which of the following is not likely to be a tumor suppressor?
A growth factor receptor
Cell proliferation in culture is normally limited by
contact inhibition.
In normal cells, p53 protein acts as
-None of these
Choose the best answer:
a. Ionizing radiation is emitted at low levels by many natural objects, including some rocks and gases.

b. The products of tumor suppressor genes stimulate cell proliferation, while the products of proto-oncogenes inhibit cell proliferation.

c. The nucleic acid of retroviral provirus is composed of RNA.

d. both A and B are correct statements.

e. All of the above are correct statements.
A
Choose the best answer:
a. Some carcinogens act on the genome directly, while others are converted to mutagenic substances by the cells's enzymes.

b. Terminally differentiated cells are noncancerous, normal cells.

c. The process of relaying a growth-stimulatory or growth-inhibitory signal in response to an extracellular factor binding at the cell surface is called intercellular signaling.

d. both A and B are correct statements.

e. All of the above are correct statements.
D. both A and B
Choose the best answer:
a. Wild-type mutator genes produce substances that induce point mutations and chromosomal rearrangements.

b. Inherited mutant tumor suppressors produce a dominant susceptibility to cancer, but the mutant alleles are actually recessive in the cancer.

c. The only genes necessary for the retroviral lifecycle are gag and pol.

d. both A and B are correct statements.

e. All of the above are correct statements.
B
Which of the following is(are) considered carcinogenic?
Alkylating agents, UV light, and X rays are all carcinogens.
A mutation in which type of gene may result in the development of cancer?
tumor suppressor genes, proto-oncogenes, and mutator genes
A neoplastic cell
has lost control over the process of cell division.
A type of gene whose action stimulates unregulated cell proliferation is a(n)
oncogene.
Which of the following is a true statement?
a. All tumors are cancerous.

b. A malignant tumor is cancerous.

c. A benign tumor is cancerous.

d. All of the above statements are true.
B
Telomere shortening, which leads to replicative senescence in cells, is a result of
the inability of DNA polymerase to replicate the very ends of the chromosomes occupied by the RNA primer, and the absence of telomerase in "normal" cells.
In pedigrees showing the inheritance of retinoblastoma in families, the disease appears to be a ___ trait.
dominant
Three key genes of retroviruses are
gag, pol, and env
Proto-oncogene products are generally proteins that normally
stimulate cell growth.
The src family of oncogenes normally encode which type of protein?
protein kinase
The enzyme carried by RNA viruses that synthesizes a DNA copy of the viral RNA genome is
reverse transcriptase
The initiation of cancer in an organism is called
oncogenesis
Which of the following is NOT a cell cycle checkpoint?
M to G1
What is the role of tumor suppressor genes in cancer?
Tumor suppressors are so named because when they are disabled, unregulated cell proliferation results.
Which of the following is a DNA virus that causes cancer in women?
papillomavirus
Mutations in normally growth-inhibitory genes such as tumor suppressors express _____________, whereas mutations of proto-oncogenes leading to excessive cell growth express ____________.
recessively; dominantly
Which of the following statements is true?
a. The product of the TP53 gene is a protein kinase.

b. Mutations in the TP53 gene cause 50% of all cancers.

c. The TP53 gene is a mutator gene.

d. Roughly half of the people with cancer show a mutation in a TP53 gene.
Roughly half of the people with cancer show a mutation in a TP53 gene.
Which of the following is a correct match of a retroviral gene and the protein it encodes?
pol-reverse transcriptase
A v-onc may be found in
viruses
The virus responsible for acquired immunodeficiency syndrome (AIDS) is a(n)
an RNA virus or a retrovirus.
When proto-oncogenes are mutated, they may
induce tumor formation.
Put the following steps of the retrovirus life cycle in proper order: A. The RNA genome is released from the viral particle. B. Reverse transcriptase makes a complementary DNA copy of the RNA genome. C. Proviral DNA integrates into the host chromosome. D. Reverse transcriptase copies the DNA to produce double-stranded DNA.
A-B-D-C
Favorable alleles of genes can cause selection for an allele of an unrelated linked gene, a phenomenon known as
genetic hitchhiking.
Sickle-cell heterozygotes have a selective advantage, exhibiting
overdominance.
Immigration of individuals with different allele frequencies into a population causes
gene flow.
Hybrid sterility is an example of
postzygotic isolation.
Very small, isolated populations are subject to
genetic drift.
In the Hardy-Weinberg model, the ideal population is
-ALL OF THESE
-very large
-randomly mating
-free of mutations
-nonmigrating
If there are two alleles of a gene, B and b, and the frequency of the B allele (p) is 0.90, the frequency of the b allele (q) is
0.10
For alleles of genes in Hardy-Weinberg equilibrium, the frequency of heterozygotes is represented as
2pq
Which of the following methods is least useful for assessing levels of genetic variation in populations?
Phenotypic observation
If the genotypic frequencies in a population at Hardy-Weinberg equilibrium are 0.418 homozygous dominants, 0.457 heterozygotes, and 0.125 homozygous recessives, what is the frequency of the recessive allele?
0.35
Allele frequencies can change across the geographic range of a species according to climate, geological features, or direction in the range. For instance, a certain allele frequency might go up along with the elevation or down as you go south in the species' range. This systematic change in frequency is referred to as
a cline
Which of the following is not a form of genetic drift?
Heterozygote advantage
Genetic drift may lead to
loss of genetic variation in a population.
For a gene A, a geneticist studying a population of butterflies found the following genotypes:
108 AA butterflies
144 Aa butterflies
48 aa butterflies
What is the observed genotypic frequency of Aa individuals?
0.48
For a gene A, a geneticist studying a population of butterflies found the following genotypes:
108 AA butterflies
144 Aa butterflies
48 aa butterflies
What is the frequency of the a allele in the butterfly population?
0.40
Synonymous mutations are found much more frequently than nonsynonymous mutations because
changes in the amino acid sequence of proteins are likely to be harmful.
________ is the ultimate source of genetic variation in populations.
mutation
A population genetic study of a certain insect revealed four alleles for the GPI (glucose-phosphate isomerase) locus. How many different genotypic classes should be found?
10
Heterozygotes for the sickle-cell allele show higher fitness than either homozygote genotype in malarial regions. This is an example of
overdominance.
Although bees carry pollen from tulip flowers to the blossoms on cherry trees, hybrid seeds are not produced because of
gametic isolation
Choose the best answer.
a. For two populations to remain genetically homogenized, a significant proportion of the population of each must be exchanged at least every other generation.

b. When the population mean for a given measured trait is observed to decline over the course of several generations, it is an example of disruptive selection.

c. The genetic variation between human "races," such as Africans and Europeans, is less than the variation within a single race.

d. Both A and B are correct.

e. All of the above are correct.
C
Choose the best answer.
a. The Hardy-Weinberg relationship cannot be used to compute allele frequencies when one or more alleles are recessive.

b. Two closely related insect species are active at different times of day, with one diurnal and the other nocturnal. This is an example of spatial isolation.

c. A selection coefficient of 1 means zero fitness.

d. Both A and B are correct.

e. All of the above are correct.
C
Choose the best answer.
a. Survival is the single most important process in evolution by natural selection.

b. According to the Hardy-Weinberg principle, at equilibrium the allele frequencies are dependent on the genotypic frequencies.

c. The frequency of a recessive X-linked allele is equal to the phenotypic frequency of males exhibiting that allele.

d. Both A and B are correct.

e. All of the above are correct.
C
What is replacement bias in homologous proteins?
Amino acids are most likely to be replaced with amino acids with similar chemical characteristics in homologous proteins.
Genes evolve as a result of ___ in DNA.
-ALL OF ABOVE
-mutations
-duplications
-tranpositions
High rates of evolutionary change are observed in
pseudogenes
In DNA, ___ mutations appear to accumulate at a faster rate than other types of mutations.
transition
It appears that natural selection favors variability within ___ genes.
major histocompatibility complex
Multigene families in eukaryotic genomes probably evolved as a result of
gene duplication
Which of the following is a possible reason for underestimating the number of substitutions that has occurred since two homologous sequences last shared a common ancestor?
A site may have undergone multiple substitutions, and transitions accumulate at a faster rate than transversions.
Of the six codons that signify the amino acid leucine in yeast, approximately 80% of the leucine codons are UUG. This indicates that ___ is occurring.
codon usage bias
Parsimony-based sequence alignment methods rely on the assumption that
genetic mutations are rare events.
Rank the following regions of a gene in terms of the relative rate of evolutionary change, from lowest to highest rate. 5' flanking region coding sequence (nonsynonymous changes) introns 3' flanking region
B-A-C-D
Proteins that are ___ share a common ancestry.
homologous
The average synonymous substitution rate in mitochondrial DNA is ___ the rate of synonymous substitutions in nuclear genes.
ten times greater
The content of guanine and cytosine (G + C) was compared among three types of bacteria (1, 2, and 3), and it was found that 1 and 2 were more similar in (G + C) to each other than either was to bacterium 3. Using the parsimony principle, you can conclude that
1 and 2 share a more recent common ancestor than 1 and 3 or 2 and 3.
The lowest rates of evolutionary change are expected in
the coding region of functional genes.
Which of the following is the best indicator of the relative amount of expression of a gene over an organism's lifetime?
adherence of the gene to the codon usage bias of the organism
The rate of nucleotide substitution between two DNA sequences can be determined by dividing the number of substitutions (observed by sequence alignment) by
twice the divergence time.
The tree of life proposed by Woese, Pace, and others in the mid 1980s grouped organisms according to the nucleotide sequence of ___ genes in various organisms.
16S rRNA
Which of the following statements is true?
a. Different genes in the same organism evolve at approximately the same rate.

b. The same genes in different organisms evolve at approximately the same rate.

c. Different parts of the same gene evolve at different rates.

d. None of these statements is true.
C
Which of the following statements is true?
a. The majority of synonymous mutations are detrimental to fitness.

b. The majority of synonymous mutations are eliminated by natural selection.

c. The majority of nonsynonymous mutations will become permanent substitutions.

d. The rate of synonymous mutation is greater than the observed rate of nonsynonymous mutation.
D
What does bootstrapping measure in phylogenetic tree reconstruction?
the confidence level for nodes of the inferred trees
If neutral base substitutions occur at random over time, it may be possible to use observed sequence divergence among a group of organisms as a
molecular clock.
Primate genes appear to be evolving at a slower overall rate than genes in
Primate genes appear to be evolving at a slower overall rate than genes in all of these organisms.
The molecular clock hypothesis correlates the rate of evolution to substitution rates in
homologous proteins.
Which of the following statements is true of mitochondrial DNA?
The average synonymous substitution rate is higher than that for synonymous substitutions in nuclear genes.
According to the endosymbiont theory, mitochondria and chloroplasts arose from
bacteria
Transition
An A-to-G or C-to-T mutation
Transversion:
A purine-to-pyrimidine mutation
Synonymous mutation:
A mutation that does not alter the encoded amino acid.
Nonsynonymous
A mutation that alters the encoded amino acid
Pseudogene:
Nonfunctional evolutionary remnant of a gene
Homologous proteins
share a common ancestor.
Synonymous changes that arise within coding sequences of genes
generally have no effect on the phenotype.
Indels are
small deletions or insertions that produce gaps in sequence alignments.
Higher substitution rates are seen in ________ than in ________.
introns, exons
Nonsynonymous substitutions
lead to amino acid change.
What is the number of possible unrooted trees for 5 taxa?
15
Which of the following statements about molecular evolution is true?
Different regions of the same gene evolve at different rates.
Which of the following does not provide molecular evidence for evolution?
-ALL OF THESE
With regards to the sequence alignment
G T C C A T C G G
G T C G A T C - G,
which of the following statements is not true?
There has been a gene conversion.
Which of the following mutations is considered a synonymous change?
CUU to CUA
Codon bias suggests that
some codons are selectively favored over others.
From the standpoint of evolutionary fitness, it is expected that genes with a high rate of expression will make use of amino acids that are ________ than those amino acids used by genes with a low rate of expression.
more energetically economical
Which of the following types of proteins evolves at the slowest rate?
Histones
Which of the following factors does not interfere with the interpretation of evolutionary time using the molecular clock?
Mutations due to background cosmic radiation
The greatest genetic differences found in humans are
found between individuals of African descent.
The average synonymous substitution rate in mammalian mitochondrial genes is ________ the average rate for nuclear genes.
10 times
In the unweighted pair group method (UPGMA) of determining evolutionary relationships,
-All OF THEM
-
Reconstructions of the evolutionary relationships of a set of taxa are called
phylogenetic trees.
The differences in evolutionary rates of change revealed by relative rate tests may be attributable to
-ALL OF THESE
-
_______ tend(s) to occur more frequently than ________.
-ALL OF THEM
Choose the best answer.
a. The noncoding 5' flanking region of genes is more constrained by selection than the noncoding 3' flanking region.

b. Many viruses are helped along in generating antibody-evading capsid protein variations by replication error.

c. Pseudogenes tend to have lower average substitution rates than functional genes.

d. Both A and B are correct

e. All of the above are correct
D
Choose the best answer.
a. The counterpart to the use of mtDNA to reconstruct maternal lineages is the use of chloroplast DNA to reconstruct paternal lineages.

b. High molecular similarity always reflects evolutionary relatedness.

c. Maximum confidence is a procedure for reconstructing phylogenetic trees invoking the fewest number of steps or mutations.

d. Both A and B are correct

e. None of the above are correct.
E
Choose the best answer.
a. Nuclear autosomal DNA sequence is more abundant than mtDNA and is therefore preferable for use in reconstructing events like domestication or human migration.

b. The fact that approximately 80% of the six codons that encode the amino acid leucine in yeast are UUG is an example of codon bias.

c. Genetic distance refers to the proportion of dissimilar nucleotides between two homologous sequences.

d. Both B and C are correct

e. All of the above are correct.
D
Which of the following is the best indicator of the relative amount of expression of a gene over an organism's lifetime?
adherence of the gene to the codon usage bias of the organism
mRNA levels for a specific gene can varry in response to which of the following:
-ALL OF ABOVE
-cell type
-developmental stage
-external stimuli
The goal of genome-wide expression analysis is:
to measure the RNA level for all genes in the genome of an organism.
Which of the following is not a Hybridization-based techniques for measuring the expression of genes.
southern blot
Northern blots
-BOTH
-are the oldest hybridization-based technique for measuring the expression
-measure the expression of one gene at a time.
How many samples can be compared in a Northern blot?
Depends on the number of time points taken after treatment with a hormone.
Choose the correct statement.

A. Using microarrays all genes in the genome can be measured at the same time.
B. Northern blots detect the location of a probe DNA molecule in the genome.
C. Both A and B are correct
D. none of the above are correct.
A
In a Northern Blot

A. mRNA molecules are separated on the basis of size using agarose gel electrophoresis.
B. the mRNA molecules are transfered in relative position onto a membrane such as nitrocellulose.
C. the blot is probed with a DNA probe complementry to a specific mRNA.
D. All of the above are correct.
D
In a microarray

A. mRNA molecules are separated on the basis of size using agarose gel electrophoresis.
B. the mRNA molecules are transfered in relative position onto a membrane such as nitrocellulose.
C. the blot is probed with a DNA probe complementry to a specific mRNA.
D. All of the above are correct.
E. None of the above are correct.
E
Which of the following is a critical difference between microarrays and northern blots?
In a microarray many genes can be analyzed at the same time.
When DNA probes for many genes are immobilized on a solid support, and mRNA's or cDNA's are hybridized with the immobilized probes, this is
a micorarray
Using Spotted microarrays
2 mRNA samples can be compared.
Spotted microarrays can be made using which of the following methods:

A. Photochemic synthesis of a DNA probe in place.
B. Spotting of DNA using a robot and pins that deliver a nanodrop of DNA to a specific location on a solid support
C. Spotting of DNA using inkjet printing technology.
D. B and C are both correct.
D
When green Cy3 and red Cy5 are used to label 2 RNA samples from different tissues, mRNAs hybridizing that are not differentially expressed in the 2 samples will produce ___________ spots in the final image that is produced by the combination of the red and green laser immages.Green
yellow
_______________ is a statistical technique that can be used to determine the subset of genes that are differentially expressed in a large microarray experiment.
cluster analysis
A sensitive way of measuring gene expression that relies on primers specifically binding to cDNA sequences and amplifying the sequence between the primers is:
real time PCR
Gene Chip microarrays are made using a photochemical process
requiring at least 4 times more cycles than the length of the sequence.
Choose the correct answer.

A. Microarrays have been used to analyze gene expression during the cell cycle.
B. Microarrays have been used to "genotype" cancer cells.
C. Both A and B are correct.
D. None of the above are correct
C
Serial Analysis of Gene Expression

A. is a non hybridization based method of determining gene expression.
B. is based on sequencing a series of short sequences from mRNAs.
C. Both A and B are correct.
D. None of the above are correct
C
Massively Parallel Signature Sequencing

A. is a non hybridization based method of determining gene expression.
B. determines how many times a given mRNA is represented in each cell by sequencing massive numbers of individual mRNAs.
C. Both A and B are correct.
D. None of the above are correct
C
Choose the correct statement.

A. Real-time PCR has replaced Northern blotting as the standard method of determining the expression level of one or a few genes.
B. Real-time PCR involves the determination of how many cycles of PCR are required to obtain a given amount of DNA.
C. Both A and B are correct.
D. None of the above are correct
C
Proteomics is:
the characterization of all of the proteins made by an organism.
Choose the correct answer.

A. Characterizing a proteome is considerably more complex than sequencing a genome.
B. There are far more proteins than genes in a eukaryotic organism.
C. Both A and B are correct.
D. neither A nor B is correct.
C
Choose the correct answer.

A. Humans possess approximately 25,000 genes, but are estimated to have between 200,000 and 2 million unique proteins.
B. The exact proteins that are expressed at any given moment in a particular cell type or tissue depend on a person's age, health, and environmental stimuli.
C. Both A and B are correct.
D. neither A nor B is correct.
C
Explain how so many proteins could be made from so few genes?
Many of these proteins are produced by alternative intron/exon splicing.
__________________ are defined as any changes to the covalent bonds of a protein after it has been fully translated.
Posttranslational modifications
Which of the following is not a type of protein modification regulating the activity of the protein.
formylation to make N-formyl-methionine
More than 2000 peptides can be separated ont the basis of molecualr size and charge using
2 dimentional gel electrophoresis.
Choose the correct answer.

A. The end result of 2-D gel electrophoresis is that each protein will have a unique x-y position on the 2-D gel.
B. Proteins that are identified by their unique position on a 2-D gel can be removed for further experimental analysis.
C. Both
D. Neither A or B are correct.
C
______________ is a technique that can be utilized to identify specific peptide fragment sequences in proteins extracted from 2-D gels.
Mass spectrometry
A ____________ can be utilized to analyze thousands of proteins simultaneously.
protein chip
____________________ is a method that systematically examines the interaction between 2 proteins.
Yeast 2 hybrid
Fusing a gene with a gene for green florescent protein can be utilized to
localize the place in a cell where the protein normally functions.
In order to prove that an enzyme functions in a specific metabolic pathway
standard methods of biochemical analysis are utilized to determine the reaction catalyzed by the enzynme.