Question 1

If you crossed a true-breeding yellow-seed plant (AA) with a heterozygous yellow-seed plant (Aa), offspring:

Accepted Answer

A) genotypes would be 1 AA:2 Aa. 
B) genotypes would be 1 Aa:1 aa. 
C) genotypes would be 1 AA:1 Aa. 
D) phenotypes would be 1/2 yellow-seed plants and 1/2 green-seed plants. 
E) genotypes would be 1 Aa:1 aa and would be 1/2 yellow-seed plants and 1/2 green-seed plants.

Question 2

Which of the following statements is TRUE regarding Hippocrates' theory of trait inheritance?

Accepted Answer

A) This theory influenced later evolutionary biologists, such as Charles Darwin and Jean-Baptiste Lamarck. 
B) This theory stated that each body part could produce heritable substances that could be passed onto progeny. 
C) This theory was likely the first to postulate how specific traits are inherited. 
D) This theory supported the idea that characteristics, such as muscle strength, can be passed from parents to offspring. 
E) All of these choices are correct.

Question 3

In 1891, August Weismann reported an experiment in which he cut the tails off 10 mice in each of 19 consecutive generations. The expected result is:

Accepted Answer

A) after the first generation of amputation, the progeny are born with no tails. 
B) offspring are born with progressively shorter tails in each generation. 
C) offspring are born with tails that are the same length as their parents for a few generations, but subsequent generations of offspring have shorter tails. 
D) all generations of offspring have tails of approximately the same length.

Question 4

You cross a true-breeding stock of black (BB) mice with skinny (SS) toes to a stock of white (bb) mice with fat (ss) toes. From this, you produce an F1 generation of black mice with skinny toes (Bb,Ss). If the single genes responsible for coat color and toe appearance do not sort independently, then you would expect to see:

Accepted Answer

A) more than 75% of your F2 black mice with skinny toes. 
B) more than 25% of your F2 black mice with fat toes.

Question 5

Imagine that a researcher is constructing a pedigree for a trait he expects to show recessive inheritance in humans. What are the likely characteristics of this trait?

Accepted Answer

A) This trait may not occur within every generation of a familyF1F1F1S1F1F1F10it could be said to "skip" generations. 
B) The parents of children who have this trait may not themselves be affected. 
C) Both males and females within a given family can have this traitF1F1F1S1F1F1F10it doesn't appear to be sex-specific. 
D) There may be instances of first-cousin mating in this pedigree, resulting in affected children. 
E) All of these choices are correct.

Question 6

In the F2 generation of a homozygous round (AA) × homozygous wrinkled (aa) cross in peas, two round seeds are chosen at random. What is the probability that one is AA and the other Aa?

Accepted Answer

A) (1/3)2 
B) (2/3)(1/3) 
C) 2(2/3)(1/3) 
D) (2/3)2

Question 7

In pea plants, flowers are either white or purple; the purple color is produced by pigments called anthocyanins. The production of anthocyanins is a two-step process: the first is controlled by the C gene and the second by the P gene. Both genes must produce functional proteins for anthocyanin to be produced. For each gene, the dominant (C and P) alleles produce functional proteins. Which of the following genotypes will produce white (no pigment) flowers?

Accepted Answer

A) ccPP 
B) CcPP 
C) CCpp 
D) ccPP and CcPP 
E) ccPP and CCpp

Question 8

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A freckled tongue-roller could have which of the following genotypes?

Accepted Answer

A) RRFF 
B) RrFf 
C) rrFF 
D) RRFF and RrFf only 
E) All of these choices are correct.

Question 9

In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, A- means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect coat color in Duroc pigs. Each gene has two alleles, one of which is dominant for coat color. Genotypes of the form A- B- are red, those of the form A- bb and aa B- are sandy, and genotype aa bb is white. What ratio of red : sandy : white is expected from the cross Aa Bb × Aa Bb?

Accepted Answer

A) 10:3:3 
B) 9:3:4 
C) 12:3:1 
D) 9:6:1

Question 10

A Punnett square is merely a graphical way to depict the expression:

Accepted Answer

A) (1/2 A + 1/2 a). 
B) (1/2 A + 1/2 a)2. 
C) (1/2 A + 1/2 a)3. 
D) (3/4 A + 1/4 a).

Question 11

In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, W- means the individual has either the genotype WW or Ww. In summer squash, genotypes W- G- and W- gg are white, ww G- are yellow, and ww gg are green. W and G show independent assortment. What cross would yield white and yellow progeny in the ratio of 1:1?

Accepted Answer

A) WW gg × ww gg 
B) WW Gg × Ww GG 
C) Ww Gg × Ww Gg 
D) WW gg × ww GG 
E) Ww Gg × ww GG

Question 12

In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, A- means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect the shape of the seed capsule in the broadleaf weed known as shepherd's purse. Each gene has two alleles, one of which is dominant for the shape of the seed capsule. Genotypes of the form A- B-, A- bb, and aa B- have triangular seed capsules, whereas the seed capsules of aa bb genotypes are ovoid. What ratio of triangular : ovoid is expected from the cross Aa Bb × Aa Bb?

Accepted Answer

A) 9:7 
B) 10:6 
C) 12:4 
D) 13:3 
E) 15:1

Question 13

A researcher is creating pedigrees for a trait he suspects to be dominant in humans. What are some of the likely features of his pedigrees for families with this trait?

Accepted Answer

A) Only females will have this dominant trait. 
B) All the offspring of a mating where one parent has the trait will themselves be affected. 
C) The occurrence of mating between individuals with this trait will be high, because all dominant traits are common within any given population. 
D) None of the answer options is correct.

Question 14

The use of the multiplication rule requires which of the following?

Accepted Answer

A) The events being considered are associated. 
B) The events being considered occur independently.

Question 15

Mendel's experiments with garden peas differed from those of other plant hybridizers of the time in that Mendel:

Accepted Answer

A) studied true-breeding strains instead of poorly defined material. 
B) focused on a small number of easily contrasted traits instead of a large number of more complex traits. 
C) quantified his results and looked for statistical patterns instead of simply noting the presence or absence of a trait among a group of offspring. 
D) performed no crosses between strains, whereas other hybridizers did. 
E) studied true-breeding strains, focused on a small number of easily contrasted traits, and quantified results.

Question 16

The phenotype ratio of the progeny of a cross between two individuals with a trait that displays incomplete dominance is:

Accepted Answer

A) 1:3. 
B) 1:1:1. 
C) 1:2. 
D) 1:2:1.

Question 17

A true-breeding black rabbit is crossed with a true-breeding white rabbit. If the black color trait is dominant, which of the following represents the expected phenotype of an F2 generation consisting of 8 individuals?

Accepted Answer

A) 8 black rabbits, 0 white rabbits, 0 grey rabbits 
B) 2 black rabbits, 2 white rabbits, 4 grey rabbits 
C) 0 black rabbits, 0 white rabbits, 8 grey rabbits 
D) 4 black rabbits, 2 white rabbits, 2 grey rabbits 
E) 6 black rabbits, 2 white rabbits, 0 grey rabbits

Question 18

Consider a gene with four alleles A1, A2, A3, and A4. How many distinct genotypes are possible, taking into account both homozygous and heterozygous genotypes?

Accepted Answer

A) 6 
B) 7 
C) 8 
D) 9 
E) 10

Question 19

Imagine two different pea plant strains: one of which has a trait that is produced by the interaction of many genes, and the other of which has a trait that is produced by a single gene with two alleles and incomplete dominance. If each of these pea plant strains self-fertilizes, how would the progeny of each cross differ?

Accepted Answer

A) They would not differ, and progeny of both crosses would have an array of phenotypes that vary continuously across a range. 
B) The progeny from the cross of the plant with the single-gene trait would all be identical, whereas the progeny from the cross of the plant with the multiple-gene trait would vary continuously across a spectrum. 
C) The progeny from the cross of the plant with the single gene trait would have three phenotypes, whereas the progeny of the cross of the plant with the trait caused by many genes would have a more complex array of phenotypes.

Question 20

A true-breeding black rabbit is crossed with a true-breeding white rabbit to produce an F1 generation with 8 individuals. If blending inheritance were true, which of the following would represent the expected phenotype of the F1 generation?

Accepted Answer

A) 8 black rabbits, 0 white rabbits, 0 grey rabbits 
B) 2 black rabbits, 2 white rabbits, 4 grey rabbits 
C) 0 black rabbits, 0 white rabbits, 8 grey rabbits 
D) 4 black rabbits, 2 white rabbits, 2 grey rabbits 
E) 6 black rabbits, 2 white rabbits, 0 grey rabbits

Exam 16: Mendelian Inheritance

If you crossed a true-breeding yellow-seed plant (AA) with a heterozygous yellow-seed plant (Aa) , offspring:

Which of the following statements is TRUE regarding Hippocrates' theory of trait inheritance?

In 1891, August Weismann reported an experiment in which he cut the tails off 10 mice in each of 19 consecutive generations. The expected result is:

Imagine that a researcher is constructing a pedigree for a trait he expects to show recessive inheritance in humans. What are the likely characteristics of this trait?

In the F₂ generation of a homozygous round (AA) × homozygous wrinkled (aa) cross in peas, two round seeds are chosen at random. What is the probability that one is AA and the other Aa?

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r) . Having freckles (F) is dominant to having no freckles (f) . A freckled tongue-roller could have which of the following genotypes?

A Punnett square is merely a graphical way to depict the expression:

A researcher is creating pedigrees for a trait he suspects to be dominant in humans. What are some of the likely features of his pedigrees for families with this trait?

The use of the multiplication rule requires which of the following?

Mendel's experiments with garden peas differed from those of other plant hybridizers of the time in that Mendel:

The phenotype ratio of the progeny of a cross between two individuals with a trait that displays incomplete dominance is:

A true-breeding black rabbit is crossed with a true-breeding white rabbit. If the black color trait is dominant, which of the following represents the expected phenotype of an F₂ generation consisting of 8 individuals?

Consider a gene with four alleles A₁, A₂, A₃, and A₄. How many distinct genotypes are possible, taking into account both homozygous and heterozygous genotypes?

A true-breeding black rabbit is crossed with a true-breeding white rabbit to produce an F₁ generation with 8 individuals. If blending inheritance were true, which of the following would represent the expected phenotype of the F₁ generation?