Question 1

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

Accepted Answer

They are circular, double-stranded DNA molecules largely devoid of associated proteins.

Question 2

Which feature distinguishes eukaryotic chromatin from prokaryotic DNA?

Accepted Answer

Eukaryotic chromatin is bound up in nucleosomes with histones H2A, H2B, H3, and H4.

Question 3

A geneticist is analyzing the DNA of a newly discovered virus. The DNA is found to be double-stranded and linear before infection, but circular after infection. Which virus is this most likely to be?

Accepted Answer

Bacteriophage lambda ($$\lambda)$$

Question 4

Which of the following is TRUE regarding mitochondrial DNA (mtDNA)?

Accepted Answer

mtDNA is double-stranded, lacks chromosomal proteins, and its replication depends on nuclear-encoded enzymes.

Question 5

Which of the following statements about polytene chromosomes is correct?

Accepted Answer

They are composed of many DNA strands and have distinctive banding patterns.

Question 6

Lampbrush chromosomes are best described as:

Accepted Answer

Large chromosomes with extensive DNA looping, found in vertebrate oocytes during prophase of meiosis.

Question 7

Which histone protein is most lysine-rich according to the provided molecular weights?

Accepted Answer

H2A

Question 8

What is the primary function of chromatin remodeling in eukaryotic cells?

Accepted Answer

To allow DNA to be accessed by DNA binding proteins for processes such as transcription.

Question 9

Which of the following regions of a eukaryotic chromosome is typically heterochromatic and transcriptionally inactive?

Accepted Answer

Centromeres

Question 10

A forensic scientist is using DNA analysis to determine kinship in a paternity case. Which type of DNA sequence is most useful for this purpose?

Accepted Answer

Microsatellites (2-4 bp repeats)

Question 11

Which of the following best describes SINEs and LINEs in the human genome?

Accepted Answer

They are dispersed repetitive elements, with LINEs acting as retrotransposons.

Question 12

If the DNA in a human cell were unwound, it would be approximately 2 meters long. Given that the nucleus is about $$5 	imes 10$$^{-6}$$ meters in diameter, what is the approximate ratio of DNA length to nuclear diameter?

Accepted Answer

$$4 	imes 10$$^{5}$$

Question 13

Which of the following is a characteristic of telomeric DNA in eukaryotes?

Accepted Answer

It consists of short tandem repeats, such as $$5'-TTAGGG-3'$$, repeated many times.

Question 14

Which statement about pseudogenes is correct?

Accepted Answer

Pseudogenes are evolutionary vestiges of genes that have lost their function due to mutations.

Question 15

A researcher finds a DNA sequence repeated hundreds of times, each repeat being 15-100 base pairs long. This sequence is most likely:

Accepted Answer

A minisatellite (VNTR)

Question 16

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

Accepted Answer

It is smaller than mitochondrial DNA and lacks introns.

Question 17

Which of the following best explains why polytene chromosomes have puff regions?

Accepted Answer

Puff regions are uncoiled areas of DNA that are visible manifestations of high gene activity.

Question 18

Which of the following is TRUE about the organization of eukaryotic genomes?

Accepted Answer

A large portion of the genome consists of non-coding regions, including pseudogenes and repetitive DNA.

Question 19

Which process is most directly affected by histone tail modifications such as acetylation, methylation, and phosphorylation?

Accepted Answer

Gene regulation and chromatin accessibility

Question 20

A mutation causes the loss of function in a gene that encodes a DNA binding protein responsible for compacting bacterial DNA. Which protein is most likely affected?

Accepted Answer

HU or H1

Chromosome Structure and DNA Sequence Organization

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