Book Review Chapter 12

Question 1

Mendel performed hybridizations by transferring pollen from the _______ of the male plant to the female ova
anther
pistil
stigma
seed

Answer 1

anther

Question 2

Which is one of the seven characteristics that Mendel observed in pea plants?
flower size
seed texture
leaf shape
stem color

Answer 2

seed texture

Question 3

7. Imagine you are performing a cross involving seed color in garden pea plants. What F1 offspring would you expect if you cross true-breeding parents with green seeds and yellow seeds? Yellow seed color is dominant over green.
   100 percent yellow-green seeds
   100 percent yellow seeds
   50 percent yellow, 50 percent green seeds
   25 percent green, 75 percent yellow seeds

Answer 3

100 percent yellow seeds

Question 4

Consider a cross to investigate the pea pod texture trait, involving constricted or inflated pods. Mendel found that the traits behave according to a dominant/recessive pattern in which inflated pods were dominant. If you performed this cross and obtained 650 inflated-pod plants in the F2 generation, approximately how many constricted-pod plants would you expect to have?
600
165
217
468

Answer 4

217

Question 5

A scientist pollinates a true-breeding pea plant with violet, terminal flowers with pollen from a true-breeding pea plant with white, axial flowers. Which of the following observations would most accurately describe the F2 generation?
75% violet flowers; 75% terminal flowers
75% white flowers in a terminal position
75% violet flowers; 75% axial flowers
75% violet flowers in an axial position

Answer 5

75% violet flowers; 75% axial flowers

Question 6

. The observable traits expressed by an organism are described as its ________.
phenotype
genotype
alleles
zygote

Answer 6

phenotype

Question 7

A recessive trait will be observed in individuals that are ________ for that trait.
heterozygous
homozygous or heterozygous
homozygous
diploid

Answer 7

Homozygous

Question 8

If black and white true-breeding mice are mated and the result is all gray offspring, what inheritance pattern would this be indicative of?
dominance
codominance
multiple alleles
incomplete dominance

Answer 8

Incomplete Dominance

Question 9

The ABO blood groups in humans are expressed as the IA, IB, and i alleles. The IA allele encodes the A blood group antigen, IB encodes B, and i encodes O. Both A and B are dominant to O. If a heterozygous blood type A parent (IAi) and a heterozygous blood type B parent (IBi) mate, one quarter of their offspring will have AB blood type (IAIB) in which both antigens are expressed equally. Therefore, ABO blood groups are an example of:
multiple alleles and incomplete dominance
codominance and incomplete dominance
incomplete dominance only
multiple alleles and codominance

Answer 9

multiple alleles and codominance

Question 10

In a mating between two individuals that are heterozygous for a recessive lethal allele that is expressed in utero, what genotypic ratio (homozygous dominant:heterozygous:homozygous recessive) would you expect to observe in the offspring?
1:2:1
3:1:1
1:2:0
0:2:1

Answer 10

1:2:0

Question 11

If the allele encoding polydactyly (six fingers) is dominant why do most people have five fingers?
Genetic elements suppress the polydactyl gene.
Polydactyly is embryonic lethal.
The sixth finger is removed at birth.
The polydactyl allele is very rare in the human population.

Answer 11

The polydactyl allele is very rare in the human population.

Question 12

farmer raises black and white chickens. To his surprise, when the first generation of eggs hatch all the chickens are black with white speckles throughout their feathers. What should the farmer expect when the eggs laid after interbreeding the speckled chickens hatch?
All the offspring will be speckled.
75% of the offspring will be speckled, and 25% will be black.
50% of the offspring will be speckled, 25% will be black, and 25% will be white.
50% of the offspring will be black and 50% of the offspring will be white.

Answer 12

50% of the offspring will be speckled, 25% will be black, and 25% will be white.

Question 13

Assuming no gene linkage, in a dihybrid cross of AABB x aabb with AaBb F1 heterozygotes, what is the ratio of the F1 gametes (AB, aB, Ab, ab) that will give rise to the F2 offspring?
1:1:1:1
1:3:3:1
1:2:2:1
4:3:2:1

Answer 13

1:1:1:1

Question 14

The forked line and probability methods make use of what probability rule?
test cross
product rule
monohybrid rule
sum rule

Answer 14

product rule

Question 15

How many different offspring genotypes are expected in a trihybrid cross between parents heterozygous for all three traits when the traits behave in a dominant and recessive pattern? How many phenotypes?
64 genotypes; 16 phenotypes
16 genotypes; 64 phenotypes
8 genotypes; 27 phenotypes
27 genotypes; 8 phenotypes

Answer 15

27 genotypes; 8 phenotypes

Question 16

Labrador retrievers’ fur color is controlled by two alleles, E and B. Any dog with the ee__ genotype develops into a yellow lab, while B_E_ dogs become black labs and bbE_ dogs become chocolate labs. This is an example of _____.
epistasis
codominance
incomplete dominance
linkage

Answer 16

epistasis

Question 17

Which of the following situations does not follow the Law of Independent Assortment?
A blond person and a brown-haired person produce three offspring over time, all of who have blond hair.
A white cow crossed with a brown bull produces roan cattle.
Mating a hog with a sow produces six female piglets.
Men are more likely to experience hemophilia than women.

Answer 17

Men are more likely to experience hemophilia than women