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60 terms

Biology Test 3

STUDY
PLAY
Which theory was disproved when Mendel observed that the F1 generation of a monohybrid cross resembled one of the parents?

the theory of blending inheritance
the chromosome theory
the theory of evolution
the theory of inheritance through acquired characteristics
the theory of blending inheritance
When do you first learn which trait is dominant?

when observing one of the parents of a monohybrid cross
when observing the genotype of a homozygote
when observing the F2 generation of a monohybrid cross
when observing the F1 generation of a monohybrid cross
when observing the F1 generation of a monohybrid cross
If flower color in peas is genetically determined and you're speaking about the hereditary determinant that produces white instead of purple flowers, you're speaking about _____.

a gamete
an F1
a gene
an allele
an allele
In constructing a Punnett square, what do you fill in along the horizontal row on the top of the diagram?

the dominant alleles
the recessive alleles
the unique gamete genotypes produced by one parent
the heterozygous alleles
the unique gamete genotypes produced by one parent
How many different traits did Mendel study in each of his dihybrid crosses?
2
Alleles segregate during _____.

S phase
G1 phase
mitosis
meiosis I
meiosis I
Eye color in Drosophila is an X-linked trait. Which of the following is NOT possible?

a female homozygous for the red eye allele of the gene
a female homozygous for the white eye allele of the gene
a male homozygous for the white eye allele
a female heterozygous for the red and white eye alleles
a male homozygous for the white eye allele
What does NOT occur when genes are linked?

incomplete dominance
complete dominance
independent assortment
segregation
independent assortment
If two carriers of an autosomal recessive genetic disease have children, what is the chance that their first child will be a carrier?

0
¼
½
¾
½
Imagine that a woman who is a carrier of an autosomal recessive genetic disease marries a man with the disease. Their only child is a girl without the disease. In a pedigree, you would show the woman as _____.

an open (unfilled) circle
a filled circle
a filled square
a half-filled square
a half-filled circle
an open square
a half-filled circle
The Hershey-Chase experiment answered the question of whether protein or DNA was the genetic material by learning if _____.

enzymes that destroyed DNA or destroyed protein prevented transformation of bacteria
DNA or protein from a virus entered bacterial cells during infection
DNA or protein migrated at the same or different rates when centrifuged
DNA could be radioactively labeled using 32P
DNA or protein from a virus entered bacterial cells during infection
The polarity of a DNA strand refers to the fact that _____.

the two ends of the strand have the same chemical groups
only A and T and G and C base pairs form
the two ends of the strand have different chemical groups
DNA lacks a hydroxyl group (OH) at one position of the ribose sugar
the two ends of the strand have different chemical groups
The Meselson-Stahl experiment was designed to answer which question?

What is the orientation of one DNA strand relative to another within the double helix?
Is a single strand of DNA polar?
What part of newly replicated DNA comes from the parental molecule and what part is newly synthesized?
Does DNA within cells exist as a double-stranded or single-stranded structure?
What part of newly replicated DNA comes from the parental molecule and what part is newly synthesized?
DNA polymerases use _____ as their substrate.

deoxyribonucleoside triphosphates (dNTPs)
four different nitrogenous bases
the 5' end of a preexisting DNA
deoxyribonucleoside monophosphates (dNMPs)
deoxyribonucleoside triphosphates (dNTPs)
Toposiomerase works to _____.

prevent twisting of DNA in front of the replication fork
open up the two strands of DNA at the replication fork
incorporate new DNA building blocks in the growing DNA strand
recognize origins of replication and open a replication bubble at these sites
prevent twisting of DNA in front of the replication fork
The primers used for DNA synthesis are _____.

short DNA sequences
proteins that bind to single-stranded DNA
short amino acid sequences (peptides)
short RNA sequences
short RNA sequences
Okazaki fragments are found _____.

in front of the replication fork
within primase
on the leading strand
on the lagging strand
on the lagging strand
How many copies of DNA polymerase III are in the replisome?

none
one
two
three
two
Telomerase is needed to _____.

open the two strands of DNA in front of the replication fork
prevent the loss of DNA from chromosome ends
allow DNA replication at the ends of chromosomes to occur in the 3' - 5' direction
create repetitive DNA sequences that allow the assembly of the kinetochore
prevent the loss of DNA from chromosome ends
Nucleotide excision repair _____.

recognizes and repairs thymine dimers in DNA
corrects errors in nucleotide excision
repairs single-strand breaks in DNA
recognizes and removes mismatched bases
recognizes and repairs thymine dimers in DNA
A null allele is _____.

a mutated form of a gene that does not make a functioning product
a mutated form of a gene that creates proteins with additional functions
a wild type (normal) form of a gene that is difficult to detect
a mutated form of a gene that creates proteins with additional segments
a mutated form of a gene that does not make a functioning product
Srb and Horowitz showed that _____.

arginine was synthesized in one step from ammonia and carbon dioxide
mutations of a single gene resulted in defects of one and only one enzyme
yeast is an excellent model organism for genetic studies
mutations of a single gene resulted in defects in multiple proteins
mutations of a single gene resulted in defects of one and only one enzyme
The idea that the sequence of bases in DNA specifies the sequence of bases in an RNA molecule, which specifies the sequence of amino acids in a protein, is _____.

the one-gene-one-enzyme hypothesis
the central dogma
the neutral theory
the Neurospora biosynthetic hypothesis
the central dogma
The process of using the information in mRNA to synthesize a protein is _____.

transcendentalism
transmogrification
translation
transcription
translation
According to the original central dogma, what is directly responsible for an organism's phenotype?

mutations
DNA
RNA
proteins
proteins
The redundancy of the genetic code is a consequence of _____.

having an equal number of codons and amino acids
having more codons than amino acids
having fewer codons than there are amino acids
having three-letter-long genetic words (codons)
having more codons than amino acids
When an amino acid is specified by more than one codon, what is usually shared by the set of codons that specifies this amino acid?

the entire base sequence
the first and second bases
the second base
the first base
the first and second bases
A point mutation that results in the substitution of one amino acid for another within a protein is a _____.

missense mutation
silent mutation
neutral mutation
beneficial mutation
missense mutation
A mutation that has no effect on fitness is a _____.

non-silenced mutation
missense mutation
neutral mutation
beneficial mutation
neutral mutation
A translocation is _____.

a karyotype
a chromosome-level mutation
a polyploid condition
an aneuploid condition
a chromosome-level mutation
A promoter is _____.

a sequence in RNA that promotes the release of RNA polymerase from DNA
a protein that associates with bacterial RNA polymerase to allow it to bind to DNA
a sequence in DNA that binds RNA polymerase near the site for transcription
one or more eukaryotic proteins that bind to DNA near the start of a gene
a sequence in DNA that binds RNA polymerase near the site for transcription
Which of the following statements is correct?

Sigma factor is needed to recognize the transcriptional termination signal.
During elongation, the RNA strand is extended in a 5' to 3' direction.
The bacterial RNA holozyme is used during the elongation phase of transcription.
The bacterial promoter lies just downstream of the start site of transcription.
During elongation, the RNA strand is extended in a 5' to 3' direction.
In eukaryotes, when mRNA is hybridized to complementary DNA, _____.

introns loop out as single-stranded regions of RNA
exons loop out as single-stranded regions of DNA
exons loop out as single-stranded regions of RNA
introns loop out as single-stranded regions of DNA
introns loop out as single-stranded regions of DNA
During splicing, _____ recognize and remove _____.

RNAs within the ribosome; exons
snRNPs that make up the spliceosome; exons
RNAs within the ribosome; introns
snRNPs that make up the spliceosome; introns
snRNPs that make up the spliceosome; introns
5' caps and 3' poly(A) tails of eukaryotic mRNAs _____.

protect mRNA from degradation and enhance transcription
act as sites for the start and stop of translation, respectively
protect mRNA from degradation and enhance translation
mark the beginning and end of introns, respectively
protect mRNA from degradation and enhance translation
One function of polyribosomes is to _____.

increase the rate of transcription of a single gene
allow coupled transcription and translation
increase the rate of polypeptide synthesis from a single mRNA
protect the mRNA from degradation
increase the rate of polypeptide synthesis from a single mRNA
What is recognized by an aminoacyl tRNA synthetase?

the nucleotides needed to synthesize a tRNA
the set of redundant codons that specifies one amino acid
one specific codon
one amino acid and the set of tRNAs that is coupled to that amino acid
one amino acid and the set of tRNAs that is coupled to that amino acid
The wobble hypothesis explains the _____.

ability of some tRNAs to read more than one codon
fact that there are three nucleotides per codon
redundancy of the genetic code
imprecise fit between aminoacyl tRNA synthetases and their substrates
ability of some tRNAs to read more than one codon
How does the bacterial ribosome recognize where to start translation?

The small ribosomal subunit binds to the start codon.
The small ribosomal subunit binds to the 5' cap of the mRNA.
The small ribosomal subunit binds to a sequence in the mRNA just upstream of the start codon.
The small ribosomal subunit binds to the 3' poly(A) tail of the mRNA.
The small ribosomal subunit binds to a sequence in the mRNA just upstream of the start codon.
Just prior to the formation of a new peptide bond, the tRNA attached to the polypeptide chain occupies the _____ site of the ribosome.

Shine-Delgarno
A
wobble
P
P
Which of the following levels of gene expression control allows a cell to conserve the most resources?

transcriptional control
RNA splicing control
translational control
post-translational control
transcriptional control
Which of the following levels of gene expression control allows a cell to respond most rapidly to a changing environment?
post-translational control
transcriptional control
RNA splicing control
translational control
post-translational control
At which of the following stages does transcriptional control occur?
DNA mRNA protein activated protein
a
b
c
All of the listed responses are correct.
a
Which of the following is true?
Gene expression only needs to be controlled for a small set of genes.
Gene expression only needs to be controlled in bacteria.
The control of gene expression is most like the control of a light using a dimmer switch.
The control of gene expression is most like the control of a light using an on-off switch.
The control of gene expression is most like the control of a light using a dimmer switch.
An operon is _____.

a form of operator that is under positive regulation
a set of bacterial genes that are regulated together and transcribed into a single RNA
a DNA sequence that is recognized by the repressor protein
a bacterial gene that is controlled by a promoter
a set of bacterial genes that are regulated together and transcribed into a single RNA
Allosteric regulation occurs whenever _____.
CAP bound to cAMP binds to the CAP site
a regulatory molecule binds to a protein to change its shape and activity
a repressor binds to an operator
the sigma factor associated with RNA polymerase binds to the promoter
a regulatory molecule binds to a protein to change its shape and activity
The lac repressor protein binds to the operator when it is _____.

bound to glucose
not bound to lactose
not bound to cAMP
bound to cAMP
not bound to lactose
Which of the following leads to the highest rate of lac operon transcription?

high lactose levels and high glucose levels
low lactose levels and low glucose levels
high lactose levels and low glucose levels
low lactose levels and high glucose levels
high lactose levels and low glucose levels
Which of the following works in the positive regulation of the lac operon?

the CAP protein
the lac operator
the lac repressor
lactose
the CAP protein
What is adenylyl cyclase involved in?

the cell's ability to respond to lactose
the cell's ability to synthesize repressor protein
the cell's ability to synthesize the promoter
the cell's ability to respond to glucose
...the cell's ability to respond to glucose
An important difference between a bacterium and a multicellular eukaryote is that _____.
multicellular eukaryotes only respond to signals from their external environment
bacteria make little use of transcriptional regulation
bacteria make much more use of signals inside their cells
multicellular eukaryotes need to respond to signals from other cells much more than do bacteria
multicellular eukaryotes need to respond to signals from other cells much more than do bacteria
In eukaryotes, the first step in the control of gene expression is _____.

RNA processing
mRNA stability control
transcription
chromatin remodeling
chromatin remodeling
The addition of acetyl groups to histones is associated with _____.

chromatin decondensation and low levels of gene expression
chromatin decondensation and high levels of gene expression
chromatin condensation and high levels of gene expression
chromatin condensation and low levels of gene expression
chromatin decondensation and high levels of gene expression
A mechanism of inheritance that does not depend on differences in DNA sequence is _____.

histone H1-mediated inheritance
chromatin remodeling inheritance
nucleosomal inheritance
epigenetic inheritance
epigenetic inheritance
Imagine that you've discovered a regulatory sequence thousands of base pairs away from the promoter, and that when this sequence is lost due to mutation, levels of gene expression decrease sharply. This sequence is _____.

a promoter
an enhancer
a promoter-proximal element
a silencer
an enhancer
Differential gene expression is the result of different cells having different _____.

genes
nucleosomes
regulatory proteins
regulatory sequences
regulatory proteins
Alternative RNA splicing allows for the number of different _____.

primary transcripts to exceed the number of different mRNAs
genes to exceed the number of different proteins
primary transcripts to exceed the number of different genes
proteins to exceed the number of different genes
proteins to exceed the number of different genes
MicroRNAs work to _____.

decrease the binding of ribosomes to the 5' cap
destroy mRNA or block its translation
increase rates of transcription
control patterns of alternative splicing
destroy mRNA or block its translation
A hypothesis for why the control of gene expression is more complex in eukaryotes than in bacteria is _____.

the larger number of genes in eukaryotes
the need to create many differentiated cells types in eukaryotes
the larger genome sizes of eukaryotes
the need to respond to environmental signals in eukaryotes
the need to create many differentiated cells types in eukaryotes
Proto-oncogenes work to _____.
promote progression through the cell cycle when conditions are right for growth
cause cancer
prevent cancer
halt progression through the cell cycle when conditions are not right for growth
promote progression through the cell cycle when conditions are right for growth