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Mendel Final

Chapters 9 and 10
STUDY
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A plant with yellow flowers was crossed with a plant with red flowers. All of the numerous offspring had red flowers. What does this show about the genotype of the parental plant with yellow flowers?
It is homozygous recessive
A woman who can roll her tongue (presumably dominant) is married to a man who cannot. Two of their four children can roll their tongues and two cannot. What is the genotype of the parents?
Woman Aa, man aa
Assume freckles and dimples are dominant traits. Two individuals with freckles and dimples have a child with no freckles and no dimples. What are the genotypes of the parents?
Ff Dd x Ff Dd
Both parents are heterozygous for the autosomal recessive Tay-Sachs disease. If three children in a row were born with Tay-Sachs disease, what are the chances that the next child will have Tay-Sachs disease?
25%
If an organism shows a recessive phenotype, such as short pea plants, it can be:
Only tt
If you were studying the phenomena of one gene having more than one effect, you would be studying which of the following?
Pleiotropy
If your mother is homozygous recessive and your father is heterozygous for the autosomal dominant Huntington disease, what are your chances of escaping the disease?
50%
In a recessive disorder, individuals who have that recessive allele but not the disorder are referred to as:
Carriers
In guinea pigs, B = black, b = brown, S = short hair, s = long hair. What would be the expected results if a BbSs mated with a BbSs?
9 black short hair, 3 black long hair, 3 brown short hair, 1 brown long hair
In humans, brown eyes (B) are dominant over blue eyes (b). A brown-eyed woman who has a blue-eyed child would have the genotype:
Bb
In humans, brown eyes (B) are dominant over blue eyes (b). If a homozygous brown-eyed woman mates with a homozygous blue-eyed man, what would be the chances of producing a blue-eyed child?
0%
Individuals who are heterozygous for the sickle-cell disease have an increased resistance to the protozoan which causes malaria.
True
The four o'clock flower is an example of incomplete dominance. R = red, r = white, and Rr = pink. If two hybrids are crossed, what are the chances that an offspring will have pink flowers?
50%
This figure shows a human pedigree. Based on the information presented in this figure, what type of disorder would this be?
Autosomal recessive
This figure shows a dihybrid cross. What does "A" represent?
TTGG
This figure shows a dihybrid cross. What does "E" represent?
Ttgg
This figure shows a dihybrid cross. What does "C" represent?
Tall plant, yellow pod
When a trait has more than two different forms, the gene has
multiple alleles
When two different dominant alleles are both fully expressed in the phenotype, it is referred to as:
Codominance
When two or more sets of alleles affect the same trait, it is referred to as:
Polygenic inheritance
This figure shows DNA replication. What does "B" represent?
A new strand
This figure shows DNA replication. What does "E" represent?
The parental DNA region
A biologist is studying the process of how DNA is copied. What is she studying?
DNA replication
During DNA replication, which enzyme is responsible for unzipping and unwinding the original molecule of DNA?
Helicase
If 23% of a species' DNA contains adenine, how much guanine is in this species' DNA?
27%
In semiconservative DNA replication, each new double helix formed will have:
One new strand and one old strand in each helix
The enzyme that is used to join complementary DNA nucleotides together is:
DNA polymerase
The scientists credited with the discovery of the helix structure of DNA and later won the Nobel Prize are:
Watson and Crick
Which of the following best describes the chemical composition of a nucleotide?
A nitrogen-containing base, a phosphate, and a pentose sugar
Which of the following is NOT true about RNA?
RNA forms a helix
Which of the following is not a nucleotide found in DNA?
Uracil
Which of the following is not a nucleotide found in RNA?
Thymine
Which of the following is not true of DNA?
It remains constant among different species
Which of the following nitrogenous bases are correctly paired in DNA?
Adenine-thymine, guanine-cytosine
rRNA is joined with various proteins to form _____.
structures known as ribosomes needed for translation
A __________ of mRNA nucleotides is known as _________.
triplet, a codon
Each sequence of three bases on an mRNA molecule codes for_______which is brought to the mRNA by______.
a specific amino acid, a tRNA molecule carrying the exact amino acid needed
Translation occurs in the cytoplasm.
True
RNA allows DNA, which remains in the nucleus, to _____.
direct the production of polypeptides in the cytoplasm
Which occurs in the nucleus?
transcription
A
Adenine 25%
T
Thymine 25%
G
Guanine 25%
C
Cytosine 25%
In DNA complimentary base pairs are
A-T, G-C 25% + 25% + 25% + 25% = 100%
Who gets the credit for discovering DNA?
Watson and Crick
Nucleotide -5 Carbon Sugar(Deoxyribose), Phosphate Group(P&O), Nitrogen Base
Deoxyribose and P&O make up the backbone of DNA ladder
Base Pairs are attached by what?
Hydrogen Bonds(HB = weak associations)
A and T are attached by how many Hydrogen Bonds?
Two
G and C are attached by how many Hydrogen Bonds?
Three
What is a Semiconservative Molecule that can copy itself during Interphase?
DNA
DNA is a Seminconservative Molecule that can copy itself during what phase of the Cell Cycle?
Interphase
DNA unwinds and seperates caused by:
DNA Helicase
Forms the replication fork:
DNA Helicase
Adds complimentary Nucleotides to the leading strand one at at time:
DNA Polymerase
Copied backwards by breaking off in fragments:
the lagging strand
Proofreads strand and breaks off new strand:
DNA Polymerase
What assists DNA in making proteins?
RNA
Double Strand, Confined in Nucleus, A-T & C-G, Deoxyribose
DNA
Single Strand, can leave Nucleus (found) floating freely in the Cytoplasm, A-U(Uracil 25%) & C-G, Ribose
RNA
Carrier of genetic info found on DNA from nucleus to ribosome
mRNA - messenger RNA
brings complimentary Nucleotides carrying Amino Acids to Ribosome
tRNA - transfer RNA
where proteins are assembled
rRNA - Ribosomal Subunit
mRNA is a/an _______ and tRNA is a/an _______.
Codon; Anticodon
Information from DNA is used to make a complementary RNA strand
Transcription
where protein is made
Translation
_________ happens in the nucleus and ________ occurs in the cytoplasm at the Ribosome.
Transcription; Translation
________ codon are paired with complimentary _______ anticodon which carry _______ ________.
mRNA; tRNA; Amino Acids
Chemical bonds that join amino acids together to form polypeptide chains.
Peptide Bonds
Long chains of amino acids joined together by peptide bonds are known as:
Polypeptide Chains
DNA Helicase
an enzyme that unwinds the DNA double helix during DNA replication
DNA Polymerase
enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule.
Watson & Crick
nobel prize winners for correctly describing the structure of DNA as a double helix
Nucleotide
The building block of a nucleic acids (DNA & RNA), consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
5 carbon sugar
DNA->deoxyribose; RNA->ribose
phosphate group
molecule in the backbone of DNA and RNA that links adjoining bases together
Adenine
nitrogen base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
Thymine
nitrogen base found ONLY in DNA that pairs with adenine
Uracil
nitrogen base found ONLY in DNA that pairs with adenine
Cytosine
Nitrogen base that pairs with guanine in DNA and RNA
Guanine
Nitrogen base that pairs with cytosine in DNA and RNA
Hydrogen Bonds
The Weak bond that hold together complimentary bases in DNA
DNA
deoxyribonucleic acid; genetic formation in a double-helix; can replicate or reproduce itself; made of genes
RNA
ribonucleic acid; manufacture specific forms of proteins using DNA as a template; three forms: rRNA, mRNA, tRNA
rRNA
ribosomal RNA; type of RNA that makes up part of the ribosome
tRNA
Transfer RNA; type of RNA that carries amino acids to the ribosome
mRNA
Messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
codon
three mRNA nucleotides that code for a specific amino acid
anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA codon.
Transcription
process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA
Translation
The process of reading a strand of mRNA to synthesize protein. Protein translation takes place on a ribosome.
Gregor Mendel
studied the inheritance of certain traits in pea plants (known as the father of genetics)
True Breeding
organisms that produce offspring identical to themselves if allowed to self-pollinate
Particulate Theory of Inheritance
Traits are inherited as "particles,"(genes) offspring receive a "particle" from each parent
Monohybrid Cross
A cross in which only one characteristic is tracked.
Law of Segregation
Mendelian principle explaining that because each plant has two different alleles, it can produce two different types of gametes. During fertilization, male and female gametes randomly pair to produce four combination of alleles
Alleles
different form of a gene (ex. T or t)
Gene Locus
specific location of a gene on a chromosome
Dominant Allele
An allele that is fully expressed in the phenotype of a heterozygote.
Recessive Allele
an allele that is masked when a dominant allele is present
Genotype
refers to the alleles an individual receives at the time of fertilization
Homozygous
allele combination with both parts of genotype identical (example: TT or tt)
Heterozygous
allele combination with two different parts of genotype (example: Tt)
Phenotype
Physical expression of a gene - Ex. Widow's peak. "What you see"
Genotype vs. Phenotype
Genotype refers to alleles and Phenotype refers to appearance
Law of Independent Assortment
each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random
Dihybrid Cross
cross of two different traits in which the parents are heterozygous for both traits. Results in a 9:3:3:1 phenotype ratio
Punnet Square
A chart that shows all the possible combinations of alleles that can result from a genetic cross
Testcross
intentional breeding in order to determine underlying genotypes
One-trait testcross
When a heterozygous individual is crossed with one that is homozygous recessive, the results are always a 1:1 phenotype ratio;
Two-trait testcross
When an individual is heterozygous for two traits is crossed with one that is recessive for the traits, the offspring have a 1:1:1:1 phenotypic ratio;
the theory of natural selection
genetically based characteristics that enhance an animal's ability to survive, and therefore reproduce, will be passed on to future generations
autosomal chromosomes
The 22 pairs of chromosomes that are responsible for characteristics other than determination of sex.
pedigrees
family trees that show the occurrence of inherited phenotypes in several generations of related individuals
carriers
have the gene but don't show the trait
tay-sachs disease
A human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth, followed by death within a few years.
cystic fibrosis
A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by an excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated
Phenylketonuria
Genetic disorder in which the essential digestive enzyme phenylalanine hydroxylase is missing...PKU
sickle cell disease
A hereditary disease that causes normal, round red blood cells to become oblong, or sickle shaped.