Question 1

Which of the following best describes the biological definition of male and female in most animal systems?

Accepted Answer

Males produce small, motile gametes (sperm), while females produce large, generally immobile gametes (eggs).

Question 2

In humans, what is the primary genetic determinant of 'maleness'?

Accepted Answer

The SRY gene located on the Y chromosome

Question 3

Which statement about X-inactivation in female mammals is correct?

Accepted Answer

X-inactivation is random in somatic cells and occurs early in embryonic development.

Question 4

What is the formula for calculating the number of Barr bodies in a human cell?

Accepted Answer

$$N - 1$$, where $$N is $$the total number of X chromosomes

Question 5

A person with the karyotype 47,XXY has which condition?

Accepted Answer

Klinefelter syndrome

Question 6

Which gene is responsible for initiating X-inactivation in mammals?

Accepted Answer

XIST

Question 7

In Drosophila melanogaster, sex is determined by the ratio of X chromosomes to sets of autosomes. What is the expected sex of an individual with the genotype XX;AA?

Accepted Answer

Female

Question 8

Which of the following is true about the pseudoautosomal regions (PAR) of the Y chromosome?

Accepted Answer

They are present on both ends of the Y chromosome and share homology with regions on the X chromosome.

Question 9

Which of the following karyotypes is nonviable in humans?

Accepted Answer

45,Y

Question 10

A female with three X chromosomes (47,XXX) will have how many Barr bodies per somatic cell?

Accepted Answer

2

Question 11

Which of the following best explains dosage compensation in mammals?

Accepted Answer

One X chromosome is randomly inactivated in females to equalize gene expression with males.

Question 12

Which of the following is a consequence of nondisjunction during meiosis?

Accepted Answer

Sex chromosome aneuploidies such as Turner syndrome and Klinefelter syndrome

Question 13

In bees, which sex is produced from unfertilized eggs and what is their ploidy?

Accepted Answer

Male, haploid

Question 14

Which of the following statements about the SRY gene is correct?

Accepted Answer

It encodes a transcription factor that initiates male development.

Question 15

Which of the following is NOT a mechanism of sex determination found in nature?

Accepted Answer

Dosage compensation via X-inactivation

Question 16

A geneticist observes a cell with two Barr bodies. What is the most likely karyotype of this cell?

Accepted Answer

47,XXX

Question 17

Which of the following best describes the difference between gender and sex?

Accepted Answer

Sex refers to biological attributes such as chromosomes and anatomy, while gender refers to social constructs and identity.

Question 18

Which of the following is true about the number of genes on the X and Y chromosomes?

Accepted Answer

The X chromosome has approximately 1000 genes, while the Y chromosome has about 50 genes.

Question 19

Which of the following scenarios would result in a person with Turner syndrome?

Accepted Answer

Nondisjunction resulting in a 45,X karyotype

Sex Determination and Sex Chromosomes: Genetics Study Notes (Chapter 7)

Guida di studio - Domande di pratica

Study guide - Flashcard