Question 1

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

Accepted Answer

A)   1
B)   1/2
C)   1/4
D)   1/6
E)   0 E

Question 2

In humans, blue eyes are inherited as a recessive autosomal trait and color blindness is an X-linked recessive trait. A woman with blue eyes and normal color vision whose father was color-blind marries a man who also has normal color vision. He has brown eyes but his mother had blue eyes. Which of the following would you expect to be TRUE for their daughters?

Accepted Answer

A)   One-half of their daughters will have normal color vision and brown eyes; one-half of their daughters will have normal color vision and blue eyes.
B)   Their daughters will all have normal color vision and brown eyes.
C)   One-fourth of their daughters will be color-blind and have blue eyes, one-fourth of their daughters will be color-blind and have brown eyes, one-fourth of their daughters will have normal color vision and blue eyes, and one-fourth of their daughters will have normal color vision and brown eyes.
D)   Their daughters will all have normal color vision and have blue eyes.
E)   One-half of their daughters will be color-blind and have blue eyes; one-half of their daughters will be color-blind and have brown eyes. A

Question 3

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their twenties. How likely is it for a woman to have this condition?

Accepted Answer

A)   Women can never have this condition.
B)   One-fourth of the daughters of an affected man would have this condition.
C)   One-half of the daughters of an affected father and a carrier mother could have this condition.
D)   Only if a woman is XXX could she have this condition. C

Question 4

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following?

Accepted Answer

A)   a multiple allelic system
B)   sex linkage
C)   codominance
D)   incomplete dominance

Question 5

Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early twentieth century?

Accepted Answer

A)   Individuals inherit particular chromosomes attached to genes.
B)   Mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis.
C)   Homologous chromosomes give rise to some genes and crossover chromosomes to other genes.
D)   No more than a single pair of chromosomes can be found in a healthy normal cell.
E)   Natural selection acts on certain chromosome arrays rather than on genes.

Question 6

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first female child will have albinism?

Accepted Answer

A)   0
B)   1/8
C)   1/2
D)   1/4
E)   1/3

Question 7

The work of Gregor Mendel provided an answer to two prevailing hypotheses popular at the time. What were these two hypotheses?

Accepted Answer

A)   Mitosis is only typical in vertebrates. Meiosis is only typical in invertebrates.
B)   The two major hypotheses of the time were blending inheritance and inheritance of acquired characteristics.
C)   Animals use one set of rules for inheritance, and plants use a different set.
D)   Peas and other domestic plants are unsuited for studies of inheritance, but wild plants are perfectly suited.
E)   Self-fertilization is the rule in plants, whereas cross-fertilization is the rule in animals.

Question 8

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first child will be an albino?

Accepted Answer

A)   0
B)   1/8
C)   1/2
D)   1/4
E)   1/3

Question 9

Use the figure and the following description to answer the question(s) below.
-Which of the boxes marked 1-4 correspond to plants with dark leaves?

Accepted Answer

A)   1 only
B)   1 and 2
C)   2 and 3
D)   4 only
E)   1, 2, and 3

Question 10

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation and have one child out of three who is albino (without melanin pigmentation). What are the genotypes of the albino's parents?

Accepted Answer

A)   One parent must be homozygous for the recessive allele; the other parent can be homozygous dominant, homozygous recessive, or heterozygous.
B)   One parent must be heterozygous; the other parent can be homozygous dominant, homozygous recessive, or heterozygous.
C)   Both parents must be heterozygous.
D)   One parent must be homozygous dominant; the other parent must be heterozygous.
E)   Both parents must be homozygous dominant.

Question 11

Use the figure and the following description to answer the question(s) below.
-Which of the boxes marked 1-4 correspond to plants with a heterozygous genotype?

Accepted Answer

A)   1
B)   1 and 2
C)   1, 2, and 3
D)   2 and 3
E)   2, 3, and 4

Question 12

Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?

Accepted Answer

A)   incomplete dominance
B)   multiple alleles
C)   pleiotropy
D)   epistasis
E)   codominance

Question 13

Use the figure and the following description to answer the question(s) below.
-Which of the boxes marked 1-4 correspond to plants that will be true-breeding?

Accepted Answer

A)   1 and 4 only
B)   2 and 3 only
C)   1, 2, 3, and 4
D)   1 only
E)   1 and 2 only

Question 14

The following question(s) refer to the pedigree chart in the accompanying figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. 
-What is the probability that individual III-1 is Ww?

Accepted Answer

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

Question 15

The following question(s) refer to the pedigree chart in the accompanying figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. 
-What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?

Accepted Answer

A)   0 percent
B)   25 percent
C)   50 percent
D)   75 percent
E)   100 percent

Question 16

Which of the following statements about independent assortment and segregation is correct?

Accepted Answer

A)   The law of independent assortment requires describing two or more genes relative to one another.
B)   The law of segregation requires describing two or more genes relative to one another.
C)   The law of segregation requires having two or more generations to describe.
D)   The law of independent assortment is accounted for by observations of prophase I.
E)   The law of segregation is accounted for by anaphase of mitosis.

Question 17

Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that ________.

Accepted Answer

A)   new mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1
B)   the mechanism controlling the appearance of traits was different between the F1 and the F2 plants
C)   traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1 generation
D)   members of the F1 generation had only one allele for each trait, but members of the F2 had two alleles for each trait

Question 18

Hutchinson-Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility and death, usually from coronary artery disease, at an average age of 13 years. Patients, who look very old even as children, do not live to reproduce. Which of the following represents the most likely assumption?

Accepted Answer

A)   The disease is autosomal dominant.
B)   The disorder will increase in frequency in successive generations within a family.
C)   The disorder may be due to mutation in a single protein-coding gene.
D)   Each patient will have had at least one affected grandparent or parent.

Question 19

Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?

Accepted Answer

A)   1/2
B)   1/16
C)   1/8
D)   3/4
E)   9/16

Question 20

Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Therefore, the most efficient and effective treatment is which of the following?

Accepted Answer

A)   Feed them the substrate that can be metabolized into this amino acid.
B)   Transfuse the patients with blood from unaffected donors.
C)   Regulate the diet of the affected persons to severely limit the uptake of the amino acid.
D)   Feed the patients the missing enzymes in a regular cycle, such as twice per week.
E)   Feed the patients an excess of the missing product.

Exam 14: Mendel and the Gene

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following?

Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early twentieth century?

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation) . What is the probability that their first female child will have albinism?

The work of Gregor Mendel provided an answer to two prevailing hypotheses popular at the time. What were these two hypotheses?

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation) . What is the probability that their first child will be an albino?

Use the figure and the following description to answer the question(s) below. -Which of the boxes marked 1-4 correspond to plants with dark leaves?

Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation and have one child out of three who is albino (without melanin pigmentation) . What are the genotypes of the albino's parents?

Use the figure and the following description to answer the question(s) below. -Which of the boxes marked 1-4 correspond to plants with a heterozygous genotype?

Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?

Use the figure and the following description to answer the question(s) below. -Which of the boxes marked 1-4 correspond to plants that will be true-breeding?

The following question(s) refer to the pedigree chart in the accompanying figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. -What is the probability that individual III-1 is Ww?

The following question(s) refer to the pedigree chart in the accompanying figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. -What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?

Which of the following statements about independent assortment and segregation is correct?

Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that ________.

Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?

Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Therefore, the most efficient and effective treatment is which of the following?