Question 1

Which of the following best explains why sex-linked disorders are more common in males than in females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele on the X will result in the disorder.

Question 2

A woman who is heterozygous for a recessive X-linked disorder mates with a man who does not have the disorder. What is the probability that their son will have the disorder?

Accepted Answer

$$\frac{1}{2}$$

Question 3

Which of the following describes the chromosomal abnormality known as trisomy?

Accepted Answer

A cell with three copies of a particular chromosome instead of two.

Question 4

In fruit flies, the gene for eye color is located on the X chromosome. If a red-eyed female (homozygous) is crossed with a white-eyed male, what will be the eye color of the male offspring?

Accepted Answer

All male offspring will have red eyes.

Question 5

Which of the following is the best definition of a linkage map?

Accepted Answer

A map showing the relative positions of genes based on recombination frequencies.

Question 6

If two genes are located very close together on the same chromosome, which of the following is most likely?

Accepted Answer

They will be inherited together more frequently than genes that are far apart.

Question 7

A geneticist observes that the recombination frequency between two genes is 12%. What is the approximate distance between these genes on a linkage map?

Accepted Answer

$$12$$ map units (centimorgans)

Question 8

Which of the following chromosomal alterations is most likely to result in a genetic disorder due to the loss of essential genes?

Accepted Answer

Deletion

Question 9

A person with Klinefelter syndrome has the following sex chromosome composition:

Accepted Answer

XXY

Question 10

Which of the following best describes nondisjunction?

Accepted Answer

The failure of homologous chromosomes or sister chromatids to separate properly during meiosis.

Question 11

A woman is a carrier for hemophilia (an X-linked recessive disorder) and her partner is unaffected. What is the probability that their daughter will have hemophilia?

Accepted Answer

$$0$$

Question 12

Which of the following is true about mitochondrial inheritance?

Accepted Answer

Mitochondrial genes are inherited exclusively from the mother.

Question 13

Which of the following is a consequence of genomic imprinting?

Accepted Answer

Only the allele from one parent is expressed, while the other is silenced.

Question 14

A male with the genotype $$X^{N}Y$ (where N$ is the normal allele) mates with a female who is a carrier for color blindness (X$$^{N}$$X^{n}$). What is the probability that their son will be color blind?

Accepted Answer

$$\frac{1}{2}$$

Question 15

Which of the following best describes the phenomenon of dosage compensation in mammals?

Accepted Answer

One X chromosome in each female cell is randomly inactivated.

Question 16

Which of the following genetic disorders is caused by a deletion on chromosome 5?

Accepted Answer

Cri du chat syndrome

Question 17

If a sperm cell bearing a Y chromosome fertilizes an ovum, the resulting zygote is:

Accepted Answer

Male (XY)

Question 18

Which of the following is true about polyploidy in plants?

Accepted Answer

Polyploidy can result in new species with desirable agricultural traits.

Question 19

Which of the following best explains why linked genes do not always show perfect linkage?

Accepted Answer

Crossing over during meiosis can separate linked genes.

Question 20

A child is born with Down syndrome. Which chromosomal abnormality is most likely responsible?

Accepted Answer

Trisomy 21

Chapter 15: The Chromosomal Basis of Inheritance – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards