Chp 14 and 15 Review

Multiple Choice Questions

If a plant variety is true-breeding for a dominant trait, then _____.

A. if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny

B. the plant is heterozygous for the trait C. if the plant were crossed with a heterozygote,

one-half of the progeny would show the dominant trait, and one-half would show the recessive trait

D. if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

E. the variety is immune to mutation

If a plant variety is true-breeding for a dominant trait, then _____.

A. if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny

B. the plant is heterozygous for the trait C. if the plant were crossed with a heterozygote,

one-half of the progeny would show the dominant trait, and one-half would show the recessive trait

D. if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

E. the variety is immune to mutation

Assume tall (T) is completely dominant to dwarf (t). If a homozygous dominant individual is crossed with a

homozygous dwarf, the offspring will _____.

A. all be intermediate in height B. all be tall C. be 1/2 tall and 1/2 dwarf D. be 3/4 tall and 1/4 dwarf E. all be short

Assume tall (T) is completely dominant to dwarf (t). If a homozygous dominant individual is crossed with a

homozygous dwarf, the offspring will _____.

A. all be intermediate in height B. all be tall C. be 1/2 tall and 1/2 dwarf D. be 3/4 tall and 1/4 dwarf E. all be short

In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the

same phenotype as a plant with the genotype _____.

A. Aabbcc B. aabbcc C. AaBBcc D. AABBCc E. none of the above

In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the

same phenotype as a plant with the genotype _____.

A. Aabbcc B. aabbcc C. AaBBcc D. AABBCc E. none of the above

In carrying out his breeding studies, Mendel examined characters that had which of the following

properties?A. They were controlled by loci that were (or

behaved as if they were) on different chromosomes.

B. It was possible to isolate true-breeding varieties for each trait.

C. The traits varied in an either-or fashion. D. The characters each were controlled by a

single gene. E. All of the above.

In carrying out his breeding studies, Mendel examined characters that had which of the following

properties?A. They were controlled by loci that were (or

behaved as if they were) on different chromosomes.

B. It was possible to isolate true-breeding varieties for each trait.

C. The traits varied in an either-or fashion. D. The characters each were controlled by a

single gene. E. All of the above.

Homologous pairs of chromosomes often _____.

A. carry different genes for different traits B. differ in length C. contain different alleles D. are not both present in diploid somatic cells E. are paired up in the G2 phase of the cell cycle

Homologous pairs of chromosomes often _____.

A. carry different genes for different traits B. differ in length C. contain different alleles D. are not both present in diploid somatic cells E. are paired up in the G2 phase of the cell cycle

A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that

are _____.

A. nonhomologous B. epistatic C. codominant D. polygenic E. completely dominant

A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that

are _____.

A. nonhomologous B. epistatic C. codominant D. polygenic E. completely dominant

A man who has type B blood and a woman who has type A blood could have children of which of

the following phenotypes?A. A or B only B. AB only C. AB or O D. A, B, or O E. A, B, AB, or O

A man who has type B blood and a woman who has type A blood could have children of which of

the following phenotypes?A. A or B only B. AB only C. AB or O D. A, B, or O E. A, B, AB, or O

Which of the following matings cannot produce a child with blood type O? The letters refer to

blood types (phenotypes).A. A x A B. A x B C. O x AB D. O x O E. none of the above

Which of the following matings cannot produce a child with blood type O? The letters refer to

blood types (phenotypes).A. A x A B. A x B C. O x AB D. O x O E. none of the above

A single genetic locus that controls more than one trait is said to be _____.

A. polygenic B. epistatic C. pleiotropic D. autotrophic E. somatic

A single genetic locus that controls more than one trait is said to be _____.

A. polygenic B. epistatic C. pleiotropic D. autotrophic E. somatic

Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This

represented a _____.

A. male with Tay-Sachs B. female carrier C. male carrier D. female with Tay-Sachs E. male of unknown genotype

Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This

represented a _____.

A. male with Tay-Sachs B. female carrier C. male carrier D. female with Tay-Sachs E. male of unknown genotype

Tom's brother suffers from phenylketonuria (PKU), a recessive disorder. The brothers' parents do not have PKU. What are

the chances that Tom, who is normal for this trait, is a carrier of PKU?

A. 1/4 B. 1/3 C. 1/2 D. 2/3 E. 4/3

Tom's brother suffers from phenylketonuria (PKU), a recessive disorder. The brothers' parents do not have PKU. What are

the chances that Tom, who is normal for this trait, is a carrier of PKU?

A. 1/4 B. 1/3 C. 1/2 D. 2/3 E. 4/3

Cystic fibrosis, which is usually lethal before the age of reproduction, is a homozygous recessive trait. Why do cases continue to arise, even though people with the

disease rarely live to reproduce?A. Because new mutations continually introduce

this harmful condition into the population. B. Because the harmful allele "hides" within

heterozygous individuals, one-fourth of the offspring of two heterozygotes would be afflicted.

C. Because mosquitoes can transfer the disease from person to person.

D. Because people continue to make inappropriate lifestyle choices.

E. None of the above.

Cystic fibrosis, which is usually lethal before the age of reproduction, is a homozygous recessive trait. Why do cases continue to arise, even though people with the

disease rarely live to reproduce?A. Because new mutations continually introduce

this harmful condition into the population. B. Because the harmful allele "hides" within

heterozygous individuals, one-fourth of the offspring of two heterozygotes would be afflicted.

C. Because mosquitoes can transfer the disease from person to person.

D. Because people continue to make inappropriate lifestyle choices.

E. None of the above.

Huntington's disease is an example of a genetic disorder caused by _____.

A. a lethal dominant allele that afflicts an individual later in life

B. a nonlethal dominant allele C. a late-acting recessive allele D. homozygous recessive alleles E. multiple alleles

Huntington's disease is an example of a genetic disorder caused by _____.

A. a lethal dominant allele that afflicts an individual later in life

B. a nonlethal dominant allele C. a late-acting recessive allele D. homozygous recessive alleles E. multiple alleles

Chapter 15

Drosophila is a useful organism for genetic studies for

all of the following reasons except _____.

A. They have a long generation time. B. A single mating can produce many offspring. C. They have a small number of chromosomes. D. Drosophila chromosomes can be easily

distinguishable under a light microscope. E. All of the above

Drosophila is a useful organism for genetic studies for

all of the following reasons except _____.

A. They have a long generation time. B. A single mating can produce many offspring. C. They have a small number of chromosomes. D. Drosophila chromosomes can be easily

distinguishable under a light microscope. E. All of the above

Wild type refers to _____.

A. the most common phenotype in the natural population

B. the most extreme mutant phenotype observed in an experiment

C. any mutant genotype D. a kind of chromosomal deletion E. extranuclear genes

Wild type refers to _____.

A. the most common phenotype in the natural population

B. the most extreme mutant phenotype observed in an experiment

C. any mutant genotype D. a kind of chromosomal deletion E. extranuclear genes

If two genes are linked, _____.

A. they are on different chromosomes B. they assort independently C. they code for the same protein D. they are on the same chromosome E. they are on sex chromosomes

If two genes are linked, _____.

A. they are on different chromosomes B. they assort independently C. they code for the same protein D. they are on the same chromosome E. they are on sex chromosomes

The recombination frequency between two gene loci is _____.

A. dependent on the sex of the parent B. greater as the distance between the two loci

increases C. greater as the distance between the two loci

decreases D. dependent on whether dominant or

recessive alleles are carried at the two loci E. equal to the size of the chromosome

The recombination frequency between two gene loci is _____.

A. dependent on the sex of the parent B. greater as the distance between the two

loci increases C. greater as the distance between the two loci

decreases D. dependent on whether dominant or

recessive alleles are carried at the two loci E. equal to the size of the chromosome