Q: Which equation represents the recombination frequency between two genes, given the number of recombinant offspring and total offspring?

$$\text{Recombination frequency} = \frac{\text{Number of recombinant offspring}}{\text{Total number of offspring}} \times 100$$

Question 1

Which of the following best explains the physical basis of Mendelian inheritance?

Accepted Answer

Genes are located on chromosomes, which undergo segregation and independent assortment during meiosis.

Question 2

In Thomas Hunt Morgan's experiments with Drosophila melanogaster, what was the significance of discovering a mutant phenotype with white eyes?

Accepted Answer

It provided the first solid evidence associating a specific gene with a specific chromosome.

Question 3

Which sex determination system is used by mammals, including humans?

Accepted Answer

X-Y system

Question 4

A man with red-green color blindness (an X-linked recessive trait) and a woman who is not a carrier have children. What percentage of their sons will be colorblind?

Accepted Answer

0%

Question 5

What is the expected outcome for a female mammal heterozygous for an X-linked gene after X chromosome inactivation?

Accepted Answer

She will be a mosaic, with some cells expressing one allele and others expressing the other allele.

Question 6

Linked genes are most likely to be inherited together because:

Accepted Answer

They are located near each other on the same chromosome.

Question 7

If two genes are located far apart on the same chromosome, what is most likely to occur during meiosis?

Accepted Answer

A crossover event is more likely, increasing the recombination frequency.

Question 8

Aneuploidy is most commonly caused by which cellular event?

Accepted Answer

Nondisjunction during meiosis

Question 9

Which chromosomal alteration is most likely to result in a lethal phenotype if homozygous in a diploid embryo?

Accepted Answer

Deletion

Question 10

Polyploidy is more commonly tolerated in which group of organisms?

Accepted Answer

Plants

Question 11

Which equation represents the recombination frequency between two genes, given the number of recombinant offspring and total offspring?

Accepted Answer

$$	ext{Recombination frequency} = \frac{	ext{Number of recombinant offspring}}{	ext{Total number of offspring}} 	imes 100$$

Question 12

Which chromosomal abnormality is responsible for Down syndrome?

Accepted Answer

Trisomy of chromosome 21

Question 13

Which of the following is NOT a type of chromosomal structural alteration?

Accepted Answer

Polyploidy

Question 14

Which statement about genomic imprinting is correct?

Accepted Answer

Imprinted genes are silenced by methylation during gamete production.

Question 15

A woman who is a carrier for hemophilia (an X-linked recessive disorder) has a child with a man who does not have hemophilia. What is the probability that their son will have hemophilia?

Accepted Answer

50%

Question 16

Which of the following best describes the inheritance of mitochondrial genes?

Accepted Answer

They are inherited maternally.

Question 17

Which chromosomal abnormality is viable in humans and results in a female with only one X chromosome?

Accepted Answer

Turner syndrome

Question 18

Which of the following is true about the law of independent assortment?

Accepted Answer

It applies to genes located on different chromosomes.

Question 19

Which process is responsible for the formation of recombinant phenotypes in offspring of a testcross involving linked genes?

Accepted Answer

Crossing over

Question 20

Which of the following best describes a mosaic individual?

Accepted Answer

An individual with two populations of cells with different genotypes, developed from a single fertilized egg.

The Chromosomal Basis of Inheritance: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards