Question 1

Human pedigrees do not show the clear patterns that Mendel found in his peas because

Accepted Answer

A)  there are no dominant traits in humans. 
B)  there are no recessive traits in humans. 
C)  Punnett squares cannot be constructed for humans. 
D)  human meiosis does not result in segregation of alleles into gametes. 
E)  humans do not produce large numbers of offspring. 
A)  there are no dominant traits in humans. 
B)  there are no recessive traits in humans. 
C)  Punnett squares cannot be constructed for humans. 
D)  human meiosis does not result in segregation of alleles into gametes. 
E)  humans do not produce large numbers of offspring.

Question 2

Suppose that tomatoes with the RR genotype are red and those with rr are green.Assuming that this reflects conventional genetics shorthand of upper- and lowercase letters, which situation is true?

Accepted Answer

A)  R is dominant to r, and Rr individuals are green. 
B)  R is dominant to r, and Rr individuals are red. 
C)  r is dominant to R, and Rr individuals are green. 
D)  r is dominant to R, and Rr individuals are red. 
E)  r is dominant to R, and Rr individuals are yellow. 
A)  R is dominant to r, and Rr individuals are green. 
B)  R is dominant to r, and Rr individuals are red. 
C)  r is dominant to R, and Rr individuals are green. 
D)  r is dominant to R, and Rr individuals are red. 
E)  r is dominant to R, and Rr individuals are yellow.

Question 3

In a plant, a single locus affects both berry color and berry size.There are two mutant alleles (R1 and R2) in addition to the wild-type allele (R0).Individuals that are R0R0 have large, white berries.Individuals that are R1R1 or R0R1 have red berries, individuals that are R2R2 or R0R2 have small berries, and R1R2 individuals have berries that are both red and small.Thus,

Accepted Answer

A)  R1 is dominant to R2. 
B)  R2 is dominant to R1. 
C)  R1 and R2 exhibit incomplete dominance. 
D)  R1 and R2 exhibit pleiotropy. 
E)  R1 and R2 exhibit codominance. 
A)  R1 is dominant to R2. 
B)  R2 is dominant to R1. 
C)  R1 and R2 exhibit incomplete dominance. 
D)  R1 and R2 exhibit pleiotropy. 
E)  R1 and R2 exhibit codominance.

Question 4

Refer to the figure showing a pedigree of a sex-linked recessive trait.Note here that only individuals that are affected are shaded; unshaded individuals may or may not be carriers.   Consider the affected son of female number 5.If his wife does not carry the allele, the probability that his first son will be affected with the trait is _______ percent.

Accepted Answer

The answer of Refer to the figure showing a pedigree...

Question 5

In cats, black coat (B) is codominant with yellow (b).The coat color gene is on the X chromosome.Calico cats, which have coats with black and yellow patches, are heterozygous for the coat color alleles.Why are most calico cats females?

Accepted Answer

Males (XY) contain only one al

Question 6

In humans, red-green color blindness is determined by an X-linked recessive allele (a), whereas eye color is determined by an autosomal gene, where brown (B) is dominant over blue (b).What gametes can be formed with respect to these genes by a heterozygous, brown-eyed, color-blind male?

Accepted Answer

A)  BXa, BY 
B)  bXa, bY 
C)  BXa, bY 
D)  BX, BY, bX, bY 
E)  BXa, BY, bXa, bY 
A)  BXa, BY 
B)  bXa, bY 
C)  BXa, bY 
D)  BX, BY, bX, bY 
E)  BXa, BY, bXa, bY

Question 7

Suppose you are an advisor to a wildlife agency that has asked you to evaluate a population of deer in which antler size has shrunk considerably in the course of about three generations.The animals mate more or less randomly and are not being targeted by hunters.Which effect best accounts for the change in antler size?

Accepted Answer

A)  Environmental effects 
B)  Overdominance 
C)  Heterosis 
D)  Pleiotropy 
E)  Epistasis 
A)  Environmental effects 
B)  Overdominance 
C)  Heterosis 
D)  Pleiotropy 
E)  Epistasis

Question 8

A farmer wants to improve the quality of meat from her pigs to improve her earnings.She breeds together one pig from a line of compact individuals with very moist and tasty meat to another pig from a line of larger individuals with relatively tough and stringy meat.Most of the offspring are even larger than the large parent, with even more tender meat.What genetic effect is in action here?

Accepted Answer

A)  Heterosis 
B)  Inbreeding depression 
C)  Incomplete dominance 
D)  Epistasis 
E)  Codominance 
A)  Heterosis 
B)  Inbreeding depression 
C)  Incomplete dominance 
D)  Epistasis 
E)  Codominance

Question 9

In a plant, a single locus affects both berry color and berry size.There are two mutant alleles (R1 and R2) in addition to the wild-type allele (R0).Individuals that are R0R0 have large, white berries.Individuals that are R1R1 or R0R1 have red berries, individuals that are R2R2 or R0R2 have small berries, and R1R2 individuals have berries that are both red and small.What are the expected phenotypic ratios if you crossed R1R2 individuals to homozygous wild type?

Accepted Answer

A)  All would have small white berries. 
B)  All would have large red berries. 
C)  Half would have small white berries, and half would have large red berries. 
D)  One-third would have wild-type berries, one-third would have small white berries, and one-third would have large red berries. 
E)  One-quarter would have wild-type berries, one-half would have small white berries, and one-quarter would have large red berries. 
A)  All would have small white berries. 
B)  All would have large red berries. 
C)  Half would have small white berries, and half would have large red berries. 
D)  One-third would have wild-type berries, one-third would have small white berries, and one-third would have large red berries. 
E)  One-quarter would have wild-type berries, one-half would have small white berries, and one-quarter would have large red berries.

Question 10

Epistasis requires

Accepted Answer

A)  more than two alleles at a single locus. 
B)  two or more loci. 
C)  pleiotropy. 
D)  incomplete dominance. 
E)  codominance. 
A)  more than two alleles at a single locus. 
B)  two or more loci. 
C)  pleiotropy. 
D)  incomplete dominance. 
E)  codominance.

Question 11

Recombination events involve exchanges between _______ of the four chromatids in a tetrad.

Accepted Answer

A)  none 
B)  one 
C)  two 
D)  three 
E)  four 
A)  none 
B)  one 
C)  two 
D)  three 
E)  four

Question 12

Refer to the figure showing a pedigree of a sex-linked recessive trait.Note here that only individuals that are affected are shaded; unshaded individuals may or may not be carriers.   In generation II, female number 5 marries a man and has three children.One daughter and one son do not have the recessive trait; the other son does have the recessive trait.Based on these results, one can conclude that the mother is _______ for the trait and that the father is _______ for the trait.

Accepted Answer

a carrier (or hetero

Question 13

In Mendel's experiments, if the allele for tall (T) plants was incompletely dominant over the allele for short (t) plants, what offspring would have resulted from crossing two Tt plants?

Accepted Answer

A)  ¼ tall; ½ intermediate height; ¼ short 
B)  ½ tall; ¼ intermediate height; ¼ short 
C)  ¼ tall; ¼ intermediate height; ½ short 
D)  All tall offspring 
E)  All intermediate-height offspring 
A)  ¼ tall; ½ intermediate height; ¼ short 
B)  ½ tall; ¼ intermediate height; ¼ short 
C)  ¼ tall; ¼ intermediate height; ½ short 
D)  All tall offspring 
E)  All intermediate-height offspring

Question 14

Which statement about phenylketonuria is false?

Accepted Answer

A)  It arises from a defective enzyme. 
B)  The allele that causes phenylketonuria has pleiotropic effects. 
C)  It can lead to mental retardation. 
D)  It can lead to skin disorders. 
E)  The allele that causes phenylketonuria has incomplete dominance. 
A)  It arises from a defective enzyme. 
B)  The allele that causes phenylketonuria has pleiotropic effects. 
C)  It can lead to mental retardation. 
D)  It can lead to skin disorders. 
E)  The allele that causes phenylketonuria has incomplete dominance.

Question 15

Suppose you are a genetics counselor who is working with a 21-year-old pregnant woman who has just discovered that her father has Huntington's disease, a rare dominant autosomal trait.This disease usually develops in middle age, so people carrying this trait do not find out they have this genetic disorder until midlife.What are the chances that the child she is carrying will develop the disease? (Assume that her husband's family has no history of the disease.)

Accepted Answer

A)  10% 
B)  25% 
C)  50% 
D)  75% 
E)  100% 
A)  10% 
B)  25% 
C)  50% 
D)  75% 
E)  100%

Question 16

The parents of individuals in the F2 generation are members of the _______ generation.

Accepted Answer

A)  P 
B)  F1 
C)  F2 
D)  F3 
E)  M 
A)  P 
B)  F1 
C)  F2 
D)  F3 
E)  M

Question 17

Draw a pedigree for at least three generations and 12 individuals that shows the transmission of a dominant X-linked trait.

Accepted Answer

See the sa

Question 18

During which event would you find a sex pilus?

Accepted Answer

A)  Meiosis 
B)  Mitosis 
C)  Mutation 
D)  Epistasis 
E)  Conjugation 
A)  Meiosis 
B)  Mitosis 
C)  Mutation 
D)  Epistasis 
E)  Conjugation

Question 19

In bacteria, circular DNA molecules that replicate independent of the main chromosome are known as

Accepted Answer

A)  plasmids. 
B)  pili. 
C)  plastids. 
D)  pedigrees. 
E)  pleiotropy. 
A)  plasmids. 
B)  pili. 
C)  plastids. 
D)  pedigrees. 
E)  pleiotropy.

Question 20

If both parents have AB blood type, _______ percent of their children would be expected to have type O blood.

Accepted Answer

The answer of If both parents have AB blood type,...

Exam 12: Inheritance, Genes, and Chromosomes

Human pedigrees do not show the clear patterns that Mendel found in his peas because

Suppose that tomatoes with the RR genotype are red and those with rr are green.Assuming that this reflects conventional genetics shorthand of upper- and lowercase letters, which situation is true?

In cats, black coat (B) is codominant with yellow (b).The coat color gene is on the X chromosome.Calico cats, which have coats with black and yellow patches, are heterozygous for the coat color alleles.Why are most calico cats females?

In humans, red-green color blindness is determined by an X-linked recessive allele (a), whereas eye color is determined by an autosomal gene, where brown (B) is dominant over blue (b).What gametes can be formed with respect to these genes by a heterozygous, brown-eyed, color-blind male?

Epistasis requires

Recombination events involve exchanges between _______ of the four chromatids in a tetrad.

In Mendel's experiments, if the allele for tall (T) plants was incompletely dominant over the allele for short (t) plants, what offspring would have resulted from crossing two Tt plants?

Which statement about phenylketonuria is false?

The parents of individuals in the F2 generation are members of the _______ generation.

Draw a pedigree for at least three generations and 12 individuals that shows the transmission of a dominant X-linked trait.

During which event would you find a sex pilus?

In bacteria, circular DNA molecules that replicate independent of the main chromosome are known as

If both parents have AB blood type, _______ percent of their children would be expected to have type O blood.

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

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The parents of individuals in the F₂ generation are members of the _______ generation.