Question 1

Which of the following statements best describes the genome of most RNA viruses?

Accepted Answer

They are multipartite, with segmented genomes enclosed in different capsids.

Question 2

A scientist is studying a microorganism with a genome size of 10 Mb, composed of circular dsDNA, found in the cytoplasm, and compacted by negative supercoiling. Which organism is most likely being studied?

Accepted Answer

A bacterial cell

Question 3

Which feature distinguishes eukaryotic nuclear genomes from bacterial genomes?

Accepted Answer

Presence of introns in most genes

Question 4

A viral genome is found to be linear, associated with nucleoproteins, and lacks introns. Which of the following is most likely true about this virus?

Accepted Answer

It is a DNA virus, possibly complexed with histones.

Question 5

Which of the following best explains why viruses are considered obligate intracellular parasites?

Accepted Answer

They lack the molecular machinery for metabolic processes, reproduction, and gene expression.

Question 6

In a diploid eukaryotic organism, what is the ploidy of the gametes produced after meiosis?

Accepted Answer

Haploid (1n)

Question 7

Which equation correctly represents the restoration of the diploid number in a sexually reproducing eukaryote after fertilization?

Accepted Answer

$$1n + 1n = 2n$$

Question 8

Which of the following statements about bacterial genomes is correct?

Accepted Answer

Bacterial genomes are compacted by negative supercoiling in the nucleoid.

Question 9

A researcher finds a genome with a size of 900 Gb, linear chromosomes, and abundant repetitive sequences. Which type of genome is this most likely to be?

Accepted Answer

Eukaryotic nuclear genome

Question 10

Which of the following is a key difference between viral and bacterial genomes?

Accepted Answer

Viral genomes rarely have repetitive sequences, while bacterial genomes contain some.

Question 11

Which of the following best describes the chromatin state in eukaryotic genomes during most of the cell cycle?

Accepted Answer

Euchromatin is gene rich and relaxed; heterochromatin is gene poor and condensed.

Question 12

Which of the following is true regarding the compaction of bacterial chromosomes?

Accepted Answer

Compaction is achieved by negative supercoiling and nucleoid associated proteins (NAPs).

Question 13

Which of the following statements about viral genes is correct?

Accepted Answer

Viral genes generally lack introns, though there are exceptions.

Question 14

A student is given a genome sample and told it is haploid, contains a single chromosome, and is found in the nucleoid. Which organism is most likely the source?

Accepted Answer

Bacterium

Question 15

Which of the following best describes the relationship between genome size and organism type?

Accepted Answer

Eukaryotic genomes are generally larger than bacterial and viral genomes.

Question 16

Which of the following statements about mitochondrial and chloroplast genomes in eukaryotes is correct?

Accepted Answer

They are circular, unlike the linear nuclear chromosomes.

Question 17

Which of the following is a plausible reason why E. coli can compact its chromosome 1000-fold within the nucleoid?

Accepted Answer

Negative supercoiling and nucleoid associated proteins create looped domains.

Question 18

Which of the following best describes the ploidy and chromosome organization in most eukaryotes?

Accepted Answer

Diploid with chromosomes organized in pairs

Question 19

Which of the following is a characteristic of bacterial genes that distinguishes them from eukaryotic genes?

Accepted Answer

Bacterial genes are usually intronless and often cotranscribed in operons.

Question 20

A virus infects a host cell and requires all genome segments to meet in the host for completion of its life cycle. Which type of viral genome does this describe?

Accepted Answer

Multipartite RNA virus

Comparative Structure and Properties of Viral, Bacterial, and Eukaryotic Genomes

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