Question 1

Which gene on the Y chromosome is primarily responsible for initiating male development in humans?

Accepted Answer

SRY gene

Question 2

A patient is found to have a karyotype of 47,XXY. Which syndrome does this individual most likely have, and what is a common characteristic?

Accepted Answer

Klinefelter syndrome; tall stature and male genitalia with sterility

Question 3

Which of the following best describes the function of pseudoautosomal regions (PARs) on the sex chromosomes?

Accepted Answer

They allow synapsis and recombination between X and Y chromosomes during meiosis.

Question 4

If nondisjunction occurs during meiosis II in a human oocyte, what is the possible chromosomal composition of the resulting gametes?

Accepted Answer

Two gametes will have $$n$$ chromosomes, one will have $$n+1$$, and one will have $$n-1$$ chromosomes.

Question 5

Which of the following is a plausible explanation for the higher secondary sex ratio observed in Korea compared to the United States?

Accepted Answer

Cultural practices such as sex-specific abortion and preimplantation gender selection

Question 6

A person with the karyotype 45,X is most likely to exhibit which of the following characteristics?

Accepted Answer

Underdeveloped female genitalia and short stature

Question 7

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

Accepted Answer

It encodes the testis-determining factor and is active in XY embryos at 6–8 weeks.

Question 8

Which chromosomal abnormality is most commonly associated with tall stature and sometimes subnormal intelligence, but not constant behavioral issues?

Accepted Answer

47,XYY

Question 9

Which of the following is NOT an assumption made when predicting a 1:1 sex ratio at conception?

Accepted Answer

Egg surface is more receptive to Y-bearing sperm.

Question 10

A genetic disorder results from a mutation in a gene, but the individual has a normal chromosome count. Which of the following best describes this condition?

Accepted Answer

Difference in Sex Development (DSD)

Question 11

Which of the following best explains why aneuploidy disorders such as Down syndrome cannot typically be resolved by traditional medical treatment?

Accepted Answer

They result from numerical chromosomal abnormalities present in all cells.

Question 12

Which of the following treatments is commonly used for individuals with Differences in Sex Development (DSD)?

Accepted Answer

Hormone treatments

Question 13

Which of the following is a direct result of nondisjunction during meiosis?

Accepted Answer

Formation of gametes with abnormal chromosome numbers

Question 14

Which region of the Y chromosome does NOT recombine with the X chromosome during meiosis?

Accepted Answer

Male-specific region of the Y (MSY)

Question 15

A female patient is found to have three X chromosomes (47,XXX). Which of the following is most likely true?

Accepted Answer

She may be unaware of the abnormality and sometimes has delayed development.

Question 16

Which of the following best describes the role of the testis-determining factor (TDF)?

Accepted Answer

It triggers the formation of testes in developing embryos.

Question 17

Which of the following is a real-world application of genome editing technology discussed in the context of aneuploidy disorders?

Accepted Answer

Eliminating extra copies of chromosomes in cultured cells

Question 18

Which of the following is a common feature of Klinefelter syndrome (47,XXY)?

Accepted Answer

Male genitalia, tall stature, and sterility

Question 19

Which of the following disorders is associated with androgen insensitivity and a normal chromosome count?

Accepted Answer

Androgen Insensitivity Syndrome (AIS)

Question 20

Which of the following best explains why the theoretical sex ratio at conception is 1:1?

Accepted Answer

Males produce equal numbers of X- and Y-bearing sperm, and both types have equal viability and access to the egg.

lecture 22: Sex Determination and Chromosomal Disorders: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard