Question 1

Which of the following best describes a karyotype?

Accepted Answer

An organized visual display of all the chromosomes in a cell, arranged by size, shape, and number.

Question 2

During interphase, chromosomes occupy distinct regions within the nucleus. What are these regions called?

Accepted Answer

Chromosome territories

Question 3

Which chromosome shape is characterized by the centromere being located at the very end of the chromosome?

Accepted Answer

Telocentric

Question 4

Fluorescent in situ hybridization (FISH) is primarily used to:

Accepted Answer

Detect specific DNA sequences on chromosomes using fluorescent probes.

Question 5

Aneuploidy in humans most commonly results from which cellular event?

Accepted Answer

Nondisjunction during meiosis

Question 6

Which syndrome is caused by monosomy of the X chromosome (45,X)?

Accepted Answer

Turner syndrome

Question 7

If a cell undergoes nondisjunction during meiosis I, what is the expected outcome for the gametes produced?

Accepted Answer

All gametes will be abnormal, with two having an extra chromosome and two missing a chromosome.

Question 8

Polyploidy is most commonly observed in which group of organisms?

Accepted Answer

Plants

Question 9

Which of the following equations correctly represents the chromosome number in a triploid organism, if the haploid number is $n$?

Accepted Answer

$3n$

Question 10

A patient is found to have a partial deletion of chromosome 5, resulting in Cri-du-chat syndrome. Which genetic event most likely caused this?

Accepted Answer

Terminal deletion of a chromosome segment

Question 11

Which of the following is a consequence of polyploidy in agricultural crops?

Accepted Answer

Increased fruit size and enhanced growth

Question 12

Uniparental disomy can result from which of the following mechanisms?

Accepted Answer

Both copies of a chromosome are inherited from one parent due to nondisjunction and subsequent loss of the other parent's chromosome

Question 13

Which chromosome abnormality is most frequently associated with Down syndrome?

Accepted Answer

Trisomy 21

Question 14

Which of the following best explains the concept of gene dosage alteration?

Accepted Answer

A change in the number of copies of a gene, which can affect the amount of gene product produced.

Question 15

Which of the following is a plausible outcome of unequal crossing over during meiosis?

Accepted Answer

Some gametes will have duplications and others will have deletions of chromosome segments.

Question 16

Which chromosome banding technique is most commonly used to produce a reproducible pattern for human chromosomes?

Accepted Answer

G-banding

Question 17

A cell is found to be mosaic for Turner syndrome. What does this mean?

Accepted Answer

Some cells have a single X chromosome, while others have two sex chromosomes.

Question 18

Which of the following is true regarding heterochromatin and euchromatin?

Accepted Answer

Euchromatin is less condensed and more transcriptionally active than heterochromatin.

Question 19

If a human cell has 47 chromosomes, which condition is most likely present?

Accepted Answer

Trisomy

Question 20

Which of the following equations represents the probability $P$ of a child being born with Down syndrome (Trisomy 21) if the maternal age risk is $r$ and the number of births is $N$?

Accepted Answer

$P = r 	imes N$

Eukaryotic Chromosome Abnormalities and Molecular Organization: Study Notes

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