Question 1

You examine cells with a microscope and detect that there are two Barr bodies present in each cell.What is the most likely genotype of the cells?

Accepted Answer

A) XX 
B) XY 
C) XO 
D) XXY 
E) XXX

Question 2

Individuals with an XXY karyotype are ______ in humans and ______ in fruit flies.

Accepted Answer

A) male, male 
B) male, female 
C) female, male 
D) female, female 
E) male, intersexual

Question 3

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

Accepted Answer

A) 22 
B) 23 
C) 44 
D) 45 
E) 46

Question 4

In the following pedigree, the indicated trait is caused by what type of allele?

Accepted Answer

A) autosomal recessive 
B) autosomal dominant 
C) X-linked recessive 
D) X-linked dominant 
E) Y-linked

Question 5

The chromosomal structure to which spindle fibers attach during the mitotic divisions is referred to as a

Accepted Answer

A) chromatid. 
B) centrosome. 
C) kinetochore. 
D) metaphase plate. 
E) centromere.

Question 6

In fruit flies, brown eyes can be caused by the recessive mutations pn (prune), bw (brown) or ry (rosy), which are on the X chromosome, second chromosome, and third chromosome, respectively.Wild-type alleles for all three genes must be present for eyes to be red.Suppose that two brown-eyed flies are crossed and their progeny consist of brown-eyed sons and red-eyed daughters.Which mutation is responsible for the brown eyes in the parental female?

Accepted Answer

A) pn 
B) bw 
C) ry 
D) either bw or ry 
E) any of the three - pn, bw, or ry

Question 7

Which of the following statements applies to homologous chromatids?

Accepted Answer

A) They are attached to the same centromere. 
B) They are genetically identical. 
C) They segregate from each other at anaphase of mitosis. 
D) They contain the same genes in the same order but may have different alleles of some genes. 
E) More than one statement applies to homologous chromatids.

Question 8

Which of the following is the diploid cell destined for a specialized role in the production of gametes?

Accepted Answer

A) Somatic cell 
B) Germ cell 
C) Spermatid 
D) Polar body 
E) Ootid

Question 9

Hemophilia is caused by an X-linked recessive mutation in humans.If a woman whose paternal uncle (father's brother) was a hemophiliac marries a man whose brother is also a hemophiliac, what is the probability of their first child having hemophilia (Note: assume that there are no other cases of hemophilia in the pedigree and no hidden carriers)?

Accepted Answer

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

Question 10

Which of the following statements is FALSE?

Accepted Answer

A) Sister chromatids of the same chromosome are identical. 
B) Sister chromatids can be on nonhomologous chromosomes. 
C) Homologous chromosomes are not necessarily identical. 
D) An example of a nonhomologous chromosome pair is paternal chromosome 1 and paternal chromosome 2 in a human.

Question 11

In human oogenesis, how many chromosomes does an oogonium carry?

Accepted Answer

A) 22 
B) 23 
C) 44 
D) 46 
E) 96

Question 12

In animal gametogenesis, a single primary spermatocyte generates ______ sperm, while a single primary oocyte generates ______ egg(s).

Accepted Answer

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

Question 13

Which type of chromosome provides the basis for sex determination in many sexually reproducing organisms?

Accepted Answer

A) haploid 
B) diploid 
C) autosomes 
D) sex chromosomes 
E) homologous chromosomes

Question 14

What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?

Accepted Answer

A) Movement of sister chromatids to opposite poles at anaphase II of meiosis 
B) Movement of homologous chromosomes to opposite poles at anaphase I of meiosis 
C) Crossing over between homologous chromosomes during prophase I of meiosis 
D) Replication of chromosomes prior to meiosis 
E) Independent alignment of different homologous pairs on the metaphase I spindle

Question 15

You engineer a chromosomally XY mouse in which the SRY gene is inactivated.What do you expect to observe in this mouse?

Accepted Answer

A) The mouse will develop male anatomic features. 
B) The mouse will develop female anatomic features. 
C) The mouse's Y chromosome will convert into an X chromosome. 
D) The mouse's X chromosome will convert into a Y chromosome. 
E) The mouse will exhibit an additional X chromosome (making it XXY).

Question 16

Mitosis results in _______ chromosome number, whereas meiosis results in _______ chromosome number.

Accepted Answer

A) a doubling of, no change in 
B) no change in, no change in 
C) a reduction by half in, no change in 
D) no change in, a doubling of 
E) no change in, a reduction by half in

Question 17

In the following pedigree, the indicated trait is caused by which type of allele?

Accepted Answer

A) autosomal recessive 
B) autosomal dominant 
C) X-linked recessive 
D) X-linked dominant 
E) Y-linked

Question 18

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during _________ in the __________.

Accepted Answer

A) meiosis I, mother 
B) meiosis II, mother 
C) meiosis I, father 
D) meiosis II, father 
E) meiosis I or II, mother

Question 19

Which aspect(s) of chromosome behavior is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?

Accepted Answer

A) Segregation of sister chromatids at anaphase II of meiosis 
B) Segregation of homologous chromosomes at anaphase I of meiosis 
C) Crossing over between homologous chromosomes during prophase I of meiosis 
D) Independent alignment of different homologous pairs on the metaphase I spindle 
E) Both crossing over between homologous chromosomes during prophase I of meiosis and independent alignment of different homologous pairs on the metaphase I spindle contribute to genetic variability

Question 20

Which of the following is not a property of homologous chromosomes?

Accepted Answer

A) They pair physically during prophase of meiosis I. 
B) They exchange genes by crossing over during meiosis. 
C) They carry alleles for the same genes at the same chromosomal position. 
D) They are attached to the same centromere during G2 of the cell cycle. 
E) They segregate to opposite poles at anaphase of meiosis I.

Exam 4: The Chromosome Theory of Inheritance

You examine cells with a microscope and detect that there are two Barr bodies present in each cell.What is the most likely genotype of the cells?

Individuals with an XXY karyotype are in humans and in fruit flies.

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

In the following pedigree, the indicated trait is caused by what type of allele?

The chromosomal structure to which spindle fibers attach during the mitotic divisions is referred to as a

Which of the following statements applies to homologous chromatids?

Which of the following is the diploid cell destined for a specialized role in the production of gametes?

Which of the following statements is FALSE?

In human oogenesis, how many chromosomes does an oogonium carry?

In animal gametogenesis, a single primary spermatocyte generates sperm, while a single primary oocyte generates egg(s) .

Which type of chromosome provides the basis for sex determination in many sexually reproducing organisms?

What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?

You engineer a chromosomally XY mouse in which the SRY gene is inactivated.What do you expect to observe in this mouse?

Mitosis results in _ chromosome number, whereas meiosis results in _ chromosome number.

In the following pedigree, the indicated trait is caused by which type of allele?

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during _ in the __.

Which aspect(s) of chromosome behavior is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?

Which of the following is not a property of homologous chromosomes?

Exam 4: The Chromosome Theory of Inheritance

You examine cells with a microscope and detect that there are two Barr bodies present in each cell.What is the most likely genotype of the cells?

Individuals with an XXY karyotype are ______ in humans and ______ in fruit flies.

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

In the following pedigree, the indicated trait is caused by what type of allele?

The chromosomal structure to which spindle fibers attach during the mitotic divisions is referred to as a

Which of the following statements applies to homologous chromatids?

Which of the following is the diploid cell destined for a specialized role in the production of gametes?

Which of the following statements is FALSE?

In human oogenesis, how many chromosomes does an oogonium carry?

In animal gametogenesis, a single primary spermatocyte generates ______ sperm, while a single primary oocyte generates ______ egg(s) .

Which type of chromosome provides the basis for sex determination in many sexually reproducing organisms?

What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?

You engineer a chromosomally XY mouse in which the SRY gene is inactivated.What do you expect to observe in this mouse?

Mitosis results in _______ chromosome number, whereas meiosis results in _______ chromosome number.

In the following pedigree, the indicated trait is caused by which type of allele?

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during _________ in the __________.

Which aspect(s) of chromosome behavior is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?

Which of the following is not a property of homologous chromosomes?

Individuals with an XXY karyotype are in humans and in fruit flies.

In animal gametogenesis, a single primary spermatocyte generates sperm, while a single primary oocyte generates egg(s) .

Mitosis results in _ chromosome number, whereas meiosis results in _ chromosome number.

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during _ in the __.