Question 1

Which of the following best describes the organization of DNA in eukaryotic cells during interphase?

Accepted Answer

DNA is uncoiled and decondensed into chromatin, dispersed throughout the nucleus.

Question 2

What is the primary function of histone proteins in eukaryotic chromatin?

Accepted Answer

They provide structural support by allowing electrostatic bonding to DNA phosphates.

Question 3

Which chemical modification of histone tails is most directly associated with increased gene activity?

Accepted Answer

Acetylation

Question 4

A DNA sample is found to contain highly repetitive sequences that are not present in prokaryotes and are located in centromeric regions. What type of DNA is this?

Accepted Answer

Satellite DNA

Question 5

Which equation best represents the relationship between the number of nucleosomes ($$N$$), the length of DNA ($$L$$), and the average length of DNA per nucleosome ($$l$$)?

Accepted Answer

$$N = \frac{L}{l}$$

Question 6

Which of the following statements about mitochondrial DNA (mtDNA) is correct?

Accepted Answer

mtDNA is circular, double-stranded, and lacks chromosomal proteins.

Question 7

CpG islands are regions where cytosine is methylated. What is the effect of cytosine methylation on gene activity?

Accepted Answer

It negatively correlates with gene activity, often silencing genes.

Question 8

Which of the following best describes the chromatin remodeling process?

Accepted Answer

It relaxes chromatin structure to allow DNA-protein interactions, replication, and gene expression.

Question 9

Which of the following is a real-world application of variable number tandem repeats (VNTRs) and short tandem repeats (STRs)?

Accepted Answer

DNA fingerprinting in forensic science.

Question 10

Which equation describes the density ($$\rho) of $$satellite DNA compared to main-band DNA in a CsCl gradient ultracentrifugation experiment?

Accepted Answer

$$\rho_{satellite} \u003c \rho_{main-band}$$

Question 11

Which of the following is true about heterochromatin?

Accepted Answer

It is condensed, mostly inactive, and appears stained during interphase.

Question 12

What is the function of the centromere during mitosis and meiosis?

Accepted Answer

It facilitates chromosome movement by binding to spindle fiber microtubules.

Question 13

Which of the following best describes the structure of bacterial chromosomes?

Accepted Answer

Circular, double-stranded DNA compacted into a nucleoid with histone-like proteins.

Question 14

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

Accepted Answer

$$R = n 	imes r$$

Question 15

Which of the following statements about polytene chromosomes is correct?

Accepted Answer

They represent paired homologs that undergo many rounds of replication without strand separation or cytoplasmic division.

Question 16

The loops on lampbrush chromosomes are similar to the puffs of polytene chromosomes, as they both probably represent:

Accepted Answer

Areas of transcription

Question 17

Which of the following best describes the role of histone acetyltransferase (HAT) in chromatin structure?

Accepted Answer

It adds acetyl groups to lysine residues, neutralizing positive charge and increasing gene activity.

Question 18

Which of the following is NOT a characteristic of chloroplast DNA (cpDNA)?

Accepted Answer

It is smaller than mitochondrial DNA and contains fewer genes.

Question 19

Which of the following best describes pseudogenes?

Accepted Answer

They are DNA sequences representing evolutionary vestiges that are not transcribed.

Question 20

Which of the following statements about SINEs and LINEs is correct?

Accepted Answer

They are transposable mobile sequences dispersed throughout the genome.

Ch 11 Chromosome Structure and DNA Sequence Organization

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