Question 1

Which of the following statements 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

In Morgan's experiment with fruit flies, why did only male F2 offspring have white eyes?

Accepted Answer

The gene for eye color is located on the X chromosome, and males have only one X chromosome.

Question 4

Which of the following best explains the formation of a Barr body in female mammals?

Accepted Answer

One X chromosome in each cell is randomly inactivated and condenses into a Barr body.

Question 5

A female cat that is heterozygous for fur color genes on the X chromosome can have patches of both black and orange fur. What is the genetic mechanism behind this phenomenon?

Accepted Answer

Random X chromosome inactivation leads to a mosaic pattern of gene expression.

Question 6

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

Accepted Answer

$$17\%$$

Question 7

Which of the following best describes a genetic map?

Accepted Answer

An ordered list of genetic loci along a particular chromosome based on recombination frequencies.

Question 8

What is the result of nondisjunction during meiosis?

Accepted Answer

Gametes with abnormal numbers of chromosomes, leading to aneuploidy.

Question 9

A child is born with three copies of chromosome 21. What is the name of this condition?

Accepted Answer

Down syndrome (Trisomy 21)

Question 10

Which chromosomal alteration is illustrated by the Philadelphia chromosome, which is associated with certain leukemias?

Accepted Answer

Reciprocal translocation between chromosomes 9 and 22

Question 11

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

Accepted Answer

Cri du chat syndrome

Question 12

Which of the following statements about polyploidy is correct?

Accepted Answer

Polyploidy is more common in plants than in animals and involves more than two complete sets of chromosomes.

Question 13

Which of the following best describes genomic imprinting?

Accepted Answer

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

Question 14

A woman with a mitochondrial disorder has children with a healthy man. What is the expected inheritance pattern for the disorder in their children?

Accepted Answer

All children will inherit the disorder because mitochondria are maternally inherited.

Question 15

Which of the following is true about X-linked recessive disorders?

Accepted Answer

They are more common in males because males have only one X chromosome.

Question 16

If a gene is located 9.5 map units from another gene on the same chromosome, what does this indicate about their inheritance?

Accepted Answer

There is a $$9.5\%$$ chance of recombination between the two genes.

Question 17

Which of the following best explains why some genes on the same chromosome can have a recombination frequency close to $$50\%$$?

Accepted Answer

They are far apart on the chromosome and behave as if they are on different chromosomes.

Question 18

A male with an extra X chromosome (XXY) is diagnosed with which syndrome?

Accepted Answer

Klinefelter syndrome

Question 19

Which of the following chromosomal alterations results in a segment being reversed within a chromosome?

Accepted Answer

Inversion

Question 20

A trisomic zygote is best described as:

Accepted Answer

A zygote with three copies of a particular chromosome.

Chromosome Theory of Inheritance and Exceptions to Mendelian Genetics

Guida di studio - Domande di pratica

Study guide - Flashcard