Question 1

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

Accepted Answer

Males have only one X chromosome, so a single affected gene will result in the disorder.

Question 2

A woman who is a carrier for hemophilia (an X-linked recessive disorder) marries a normal male. What is the probability that their son will have hemophilia? Use a Punnett square to justify your answer.

Accepted Answer

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

Question 3

Which of the following best describes the difference between sex-linked and sex-influenced traits?

Accepted Answer

Sex-linked traits are determined by genes on the sex chromosomes, while sex-influenced traits are autosomal but expressed differently in males and females.

Question 4

Which chromosomal abnormality is most commonly associated with Down Syndrome?

Accepted Answer

Trisomy 21

Question 5

A pedigree shows a disease that skips generations and affects mostly males. Which inheritance pattern is most likely?

Accepted Answer

X-linked recessive

Question 6

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

Accepted Answer

Cri-du-chat syndrome

Question 7

A man with hemophilia (X-linked recessive) and a woman who is not a carrier have children. What is the probability that their daughters will be carriers?

Accepted Answer

$$1$$

Question 8

Which of the following best explains why dominant genetic disorders are less common in the population than recessive disorders?

Accepted Answer

Dominant disorders often result in early death, reducing the chance of passing the allele to offspring.

Question 9

Which of the following is a real-life example of a sex-influenced trait?

Accepted Answer

Male pattern baldness

Question 10

If nondisjunction occurs during meiosis, which of the following is a possible outcome in the resulting gametes?

Accepted Answer

Some gametes will have an extra chromosome, while others will be missing a chromosome.

Question 11

Which of the following best describes the genetic cause of cystic fibrosis?

Accepted Answer

A defective protein on chromosome 7 affecting chloride transport

Question 12

A child is born with three copies of chromosome 21. Which process most likely failed during gamete formation?

Accepted Answer

Nondisjunction

Question 13

Which of the following is true about Y-linked inheritance?

Accepted Answer

Y-linked traits are passed from fathers to all their sons.

Question 14

Which of the following best explains why females are often carriers but rarely affected by X-linked recessive disorders?

Accepted Answer

Females have two X chromosomes, so a normal allele can mask the effect of a recessive allele.

Question 15

Which of the following is a dominant-lethal genetic disorder?

Accepted Answer

Huntington disease

Question 16

A couple has a child with Tay-Sachs disease. Neither parent shows symptoms. What is the most likely genotype of the parents?

Accepted Answer

Both parents are heterozygous carriers.

Question 17

Which of the following best describes a translocation chromosomal abnormality?

Accepted Answer

A piece of a chromosome breaks off and attaches to a different chromosome.

Question 18

Which test is commonly used at birth to screen for phenylketonuria (PKU)?

Accepted Answer

Guthrie test

Question 19

Which of the following is a likely consequence of a deletion mutation in a gamete?

Accepted Answer

The resulting zygote may be nonviable or have severe developmental issues.

Question 20

Which of the following statements about the X and Y chromosomes is correct?

Accepted Answer

The X chromosome contains approximately 1000 genes, while the Y chromosome contains relatively few.

Sex-Linked Inheritance and Chromosomal Abnormalities

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드