Question 1

Which chemical modification of histone tails is most directly associated with increased gene expression by loosening chromatin structure?

Accepted Answer

Acetylation

Question 2

Histone acetyltransferase (HAT) adds an acetyl group to lysine residues on histone tails. What is the effect of this modification on the net charge of the histone protein?

Accepted Answer

It neutralizes the positive charge.

Question 3

Which enzyme is responsible for removing acetyl groups from histone tails, leading to tighter chromatin and reduced gene expression?

Accepted Answer

Histone deacetylase (HDAC)

Question 4

A forensic scientist is analyzing DNA samples using short tandem repeats (STRs). Which category of repetitive DNA do STRs belong to?

Accepted Answer

Middle repetitive tandem repeats

Question 5

Which of the following best describes the function of centromeric DNA sequences during cell division?

Accepted Answer

They facilitate chromosome movement by binding to spindle fibers.

Question 6

Which type of repetitive DNA is found in the centromeric regions of chromosomes and is not present in prokaryotes?

Accepted Answer

Satellite DNA

Question 7

A mutation in the enzyme methyltransferase would most likely affect which process?

Accepted Answer

Addition of methyl groups to histones

Question 8

Which of the following statements about heterochromatin is TRUE?

Accepted Answer

It is condensed and genetically inactive.

Question 9

Which equation best represents the relationship between the number of copies of ribosomal RNA genes ($$n) $$and the total amount of ribosomal RNA produced ($$R$$), assuming each gene produces $$r$$ units of RNA?

Accepted Answer

$$R = n 	imes r$$

Question 10

Which of the following is a characteristic of pseudogenes?

Accepted Answer

They are evolutionary vestiges with mutational alterations.

Question 11

Which of the following best describes the difference between SINEs and LINEs?

Accepted Answer

SINEs are short, while LINEs are long interspersed elements.

Question 12

During DNA fingerprinting, which repetitive DNA sequence is most commonly analyzed due to its variability among individuals?

Accepted Answer

Short tandem repeats (STRs)

Question 13

Which chemical modification of histones is most directly involved in cell cycle regulation and DNA replication?

Accepted Answer

Phosphorylation

Question 14

Which of the following is NOT a function of telomeres?

Accepted Answer

Facilitating chromosome movement during cell division

Question 15

Which equation would you use to calculate the total number of STR loci ($$N) in a $$genome if each chromosome contains $$s$$ STR loci and there are $$c$$ chromosomes?

Accepted Answer

$$N = s 	imes c$$

Question 16

Which of the following statements about repetitive DNA is FALSE?

Accepted Answer

All repetitive DNA sequences are tandemly repeated.

Question 17

A student is studying the p arm of acrocentric chromosomes in humans. Which type of gene is most likely to be found in multiple copies in this region?

Accepted Answer

Ribosomal RNA genes

Question 18

Which of the following best explains why satellite DNA can be separated from main-band DNA using ultracentrifugation in a CsCl gradient?

Accepted Answer

Satellite DNA has a different density due to its repetitive sequence composition.

Question 19

Which of the following is a real-world application of VNTRs and STRs?

Accepted Answer

DNA fingerprinting in forensics

Question 20

Which of the following best describes retrotransposons?

Accepted Answer

They are transposable elements generated via an RNA intermediate.

Chromosome Structure and DNA Sequence Organization

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