AP Bio Unit 5 Heredity

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the probability that this couple's son will be color-blind? 1 1/4 3/4 0 1/2

1/2

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt x BBtt will have black fur and long tails? 1/16 3/16 3/8 1/2

1/2

Huntington's disease is caused by a dominant allele. If one of your parents has the disease, what is the probability that you, too, will have the disease? (only one of your grandparents had the disease) 1/4 1/2 1 3/4 0

1/2

Assume that genes A and B are not linked. If the probability of allele A in a gamete in 1/2 and the probability of allele B in a gamete is 1/2, then the probability that BOTH A and B are in the same gamete is 1/2 + 1/2 1/2 - 1/2 1/2 x 1/2 1/2 ÷ 1/2

1/2 x 1/2

A woman and her spouse both show the normal phenotype for pigmentation but both had one parent who was an albino. Albinism is an autosomal recessive trait. What is the probability that their first child will be an albino? 3/4 1/4 1/2 1 0

1/4

In a cross AaBbCc x AaBbCc, what is the probability of producing the genotype AABBCC? 1/32 1/4 1/16 1/8 1/64

1/64

In a cross AaBbCc x AaBbCc, what is the probability of producing the genotype AABBCC? 1/8 1/16 1/64 1/32 1/4

1/64

In snapdragons, heterozygotes have pink flowers, whereas the two homozygotes have red flowers or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers? 75% 0% 100% 50% 25%

100%

A couple who are both carriers of the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will have cystic fibrosis? 0% 100% 25% 75% 50%

25%

In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue-eyed offspring are produced. If two blue-eyed sheep are mated with each other, what percent of the offspring will most likely have brown eyes? 50% 100% 25% 75% 0%

25%

In crossing a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozygous recessive phenotype? 0% 50% 25% 100% 75%

50%

In crossing a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozygous recessive phenotype? 50% 0% 25% 75% 100%

50%

A couple who are both carriers of the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will be phenotypically normal? 0% 100% 50% 25% 75%

75%

A child with blood type A is born to a mother with blood type B. The father must have which of the following blood types? AB only Either AB or B AB or A or O Either AB or O Either AB or A

Either AB or A

One gene masks the expression of another. What kind of inheritance is this? Multiple alleles Incomplete dominance Penetrance Pleiotropy Epistasis

Epistasis

Which is an example of a sex-linked condition? Tay-Sachs Human Height Huntington's Disease Hemophilia Turner Syndrome

Hemophilia

Which is an example of an autosomal dominant condition? Tay-Sachs Hemophilia Turner Syndrome Huntington's Disease Human Height

Huntington's Disease

One example is the ABO blood group system. What kind of inheritance is this? Incomplete dominance Multiple alleles Penetrance Epistasis Pleiotropy

Multiple alleles

One example is the ABO blood group system. What kind of inheritance is this? Penetrance Incomplete dominance Pleiotropy Epistasis Multiple alleles

Multiple alleles

Which of the following best describes the parents in a test cross? Both individuals have an unknown phenotype. Both individuals have the recessive phenotype. Both individuals have the dominant phenotype. One individual has the dominant phenotype and the other has the recessive phenotype. Both individuals are heterozygous.

One individual has the dominant phenotype and the other has the recessive phenotype.

The ability of a single gene to have multiple phenotype effects. What kind of inheritance is this? Pleiotropy Multiple alleles Epistasis Penetrance Incomplete dominance

Pleiotropy

Roan color in cattle is the result of codominance between red and white color alleles (Rr). When two roan cattle are crossed, the phenotypes of the progeny are found to be in the ratio of 1:2:1 (red : roan : white). Which of the following crosses could produce the highest percentage of roan cattle? Red x White White x Roan Red x Roan All of these crosses would give the same percentage of roan. Roan x Roan

Red x White

A child with blood type A is born to a mother with blood type B. If the father has blood type AB, which of the following statements is correct about the mother? She is homozygous for the IB allele. She contributed an IB allelle, which is codominant to the father's IA allele. She contributed an IB allele, which is recessive to the father's IA allele. She contributed an i allele, which is codominant to the father's IB allele. She contributed an i allele, which is recessive to the father's IA allele.

She contributed an i allele, which is recessive to the father's IA allele.

What is an example of an autosomal recessive condition? Hemophilia Human Height Tay-Sachs Huntington's Disease Turner Syndrome

Tay-Sachs

In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true? Both parents carry the allele for colorblindness. Neither parent carries the allele for colorblindness. The father is colorblind. The mother carries the allele for colorblindness. The father carries the allele for colorblindness.

The mother carries the allele for colorblindness.

After performing a cross in fruit flies, you find that a certain trait appears in exclusively male offspring. What would be the most likely explanation?

The trait is X-linked (sex-linked)

Which of the following is the most likely explanation for a high rate of crossing-over (recombination) between two genes? The two genes are sex-linked. The two genes are far apart on the same chromosome. The two genes code for the same protein. The two genes are both located near the centromere. The two genes are on different chromosomes.

The two genes are far apart on the same chromosome

What was the most significant result Gregor Mendel drew from his experiments with pea plants? Recessive alleles occur more frequently in the F1 generation than do dominant ones. Genes are composed of DNA. An organism that is homozygous for many recessive traits is at a disadvantage. There is considerable genetic variation in garden peas. Traits are inherited in discrete units and are not the results of "blending."

Traits are inherited in discrete units and are not the results of "blending."

In peas the trait for tall plants is dominant (T) and the trait for short peas is recessive (t). The trait for yellow seed color is dominant (Y) and the trait for green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are most likely to be the genotypes of the parents? TTYY x TTYY TtYy x TtYy TtYy x TTYy TtYY x Ttyy Ttyy x TTYy

TtYy x TTYy

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? XXc and XcY XCXc and XCY XCXC and XCY XcXc and XCY XCXC and XcY

XCXc and XCY

What is a genetic cross called between an individual of unknown genotype and a homozygous recessive? a dihybrid cross. an F1 cross. a hybrid cross. a test cross. a self-cross.

a test cross.

alleles

alternate forms of a gene

A 9:3:3:1 phenotypic ratio is characteristic of a dihybrid cross. a monohybrid cross. a trihybrid cross. linked genes. a dihybrid cross OR a trihybrid cross.

dihybrid cross

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by the alleles being codominant. the fact that a mutation has occurred. environmental factors such as soil pH. acknowledging that multiple alleles are involved. the allele for blue violet being completely dominant.

environmental factors such as soil pH.

There is good evidence for linkage when two genes occur together in the same gamete. a gene is associated with a specific phenotype. two genes work together to control a specific characteristic. genes do not segregate independently during meiosis. two characteristics are caused by a single gene.

genes do not segregate independently during meiosis.

The phenotype of the heterozygote differs from the phenotypes of both homozygotes. What kind of inheritance is this? Epistasis Pleiotropy Incomplete dominance Penetrance Multiple alleles

incomplete dominance

Roan color in cattle is the result of codominance between red and white color alleles (Rr). How would one produce a herd of pure-breeding roan-colored cattle? Cross roan with white. Cross red with white. Cross roan with roan. Cross roan with red. It cannot be done.

it cannot be done

Mendel's law of segregation was nearly impossible for most biologists to understand until there was a general understanding of mitosis. meiosis. dominance. pleiotropy. epistasis.

meiosis

The frequency of crossing over between any two linked genes is higher if they are recessive. difficult to predict. determined by their relative dominance. proportional to the distance between them. the same as if they were not linked.

proportional to the distance between them.