Question 1

Which statement best describes the chromosome theory of inheritance?

Accepted Answer

Genes are located on chromosomes, and the behavior of chromosomes during meiosis accounts for inheritance patterns.

Question 2

Why are fruit flies (Drosophila melanogaster) particularly useful for genetic studies?

Accepted Answer

They have only four pairs of chromosomes, breed quickly, and produce many offspring.

Question 3

A woman who is colorblind marries a man with normal color vision. What is the expected outcome for their children?

Accepted Answer

All daughters will be carriers and all sons will be colorblind.

Question 4

What is the function of a Barr body in female mammals?

Accepted Answer

It is an inactivated X chromosome that helps balance gene expression between males and females.

Question 5

If two genes are 17 map units apart on a chromosome, what is the expected recombination frequency between them?

Accepted Answer

$$17\%$$

Question 6

Which of the following chromosomal alterations is correctly matched with its description?

Accepted Answer

Inversion: A segment of a chromosome is reversed within the chromosome.

Question 7

A male with Klinefelter syndrome has which of the following karyotypes?

Accepted Answer

$$XXY$$

Question 8

Which of the following 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 recessive allele will cause the disorder.

Question 9

Which of the following is an example of a disorder caused by a chromosomal deletion?

Accepted Answer

Cri du chat syndrome

Question 10

A plant with a triploid (3n) chromosome number is an example of which genetic phenomenon?

Accepted Answer

Polyploidy

Question 11

Which of the following statements about mitochondrial inheritance is correct?

Accepted Answer

Mitochondrial genes are inherited only from the mother.

Question 12

A genetic map shows three genes on a chromosome: $$b$$, $$cn$$, and $$vg. $$The recombination frequency between $$b$$ and $$cn is$$ $$9\%$$, and between $$cn$$ and $$vg is$$ $$9.5\%. $$What is the recombination frequency between $$b$$ and $$vg$$?

Accepted Answer

$$17\%$$

Question 13

Which of the following best describes genomic imprinting?

Accepted Answer

The expression of an allele depends on whether it is inherited from the mother or the father.

Question 14

Which chromosomal event is most likely to result in Down syndrome?

Accepted Answer

Nondisjunction leading to trisomy 21

Question 15

Which of the following is true about linked genes?

Accepted Answer

They are located close together on the same chromosome and tend to be inherited together.

Question 16

A testcross between a dihybrid fly (gray body, normal wings) and a double mutant fly (black body, vestigial wings) produces 965 gray-normal, 944 black-vestigial, 206 gray-vestigial, and 185 black-normal offspring. What is the recombination frequency between the two genes?

Accepted Answer

$$17\%$$

Question 17

Which of the following best explains why calico cats are almost always female?

Accepted Answer

Only females have two X chromosomes, allowing for X-inactivation and mosaic fur coloration.

Question 18

Which of the following is a likely consequence of a reciprocal translocation between chromosomes 9 and 22 in humans?

Accepted Answer

Development of chronic myeloid leukemia (CML)

Question 19

Which of the following best describes the difference between aneuploidy and polyploidy?

Accepted Answer

Aneuploidy is the presence of an abnormal number of a particular chromosome, while polyploidy is the presence of more than two complete sets of chromosomes.

Chapter 15

Guida di studio - Domande di pratica

Study guide - Flashcard