Question 1

Which of the following best describes the primary structural difference between DNA and RNA nucleotides?

Accepted Answer

DNA nucleotides contain a deoxyribose sugar, while RNA nucleotides contain a ribose sugar.

Question 2

A patient is infected with an enveloped virus. Which of the following best explains why frequent handwashing with soap is effective at reducing transmission of this virus?

Accepted Answer

Soap disrupts the viral envelope, which is composed of lipids, leading to inactivation of the virus.

Question 3

During DNA replication in prokaryotes, which enzyme is responsible for synthesizing short RNA primers needed to initiate DNA synthesis?

Accepted Answer

Primase

Question 4

Which of the following statements about the directionality of DNA is correct?

Accepted Answer

DNA strands are antiparallel, with one running 5' to 3' and the other 3' to 5'.

Question 5

A mutation occurs in the gene encoding the viral spike protein of influenza. Which of the following is a likely consequence of this mutation?

Accepted Answer

The virus may evade host immune detection, potentially leading to antigenic drift.

Question 6

Which of the following best describes the process of transduction in horizontal gene transfer?

Accepted Answer

Transfer of bacterial DNA from one cell to another via a bacteriophage.

Question 7

Which of the following is a key difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Prokaryotic genomes are typically found in the cytoplasm, while eukaryotic genomes are located in the nucleus.

Question 8

Which of the following best explains why viruses are classified as nonliving microbes?

Accepted Answer

Viruses cannot carry out metabolism or reproduce independently outside a host cell.

Question 9

A scientist is studying a gene that is present on a plasmid in a bacterial cell. Which of the following statements is correct regarding plasmids?

Accepted Answer

Plasmids are extrachromosomal DNA elements that can carry genes for antibiotic resistance.

Question 10

Which of the following best describes the function of ribosomal RNA (rRNA) during translation?

Accepted Answer

rRNA forms the core of the ribosome and catalyzes peptide bond formation.

Question 11

During the lytic cycle of a bacteriophage, which of the following steps occurs immediately after biosynthesis?

Accepted Answer

Assembly (Maturation)

Question 12

Which of the following best explains why antigenic drift in influenza viruses requires a new vaccine almost every year?

Accepted Answer

Antigenic drift causes gradual accumulation of mutations in viral genes encoding surface proteins, reducing vaccine effectiveness.

Question 13

A researcher observes that a bacterial cell can take up naked DNA from its environment and incorporate it into its genome. This process is best described as:

Accepted Answer

Transformation

Question 14

Which of the following best describes the role of Okazaki fragments during DNA replication?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 15

Which of the following is a key feature of an attenuated viral strain used in vaccines?

Accepted Answer

It is a weakened form of the virus that can replicate but does not cause disease in healthy individuals.

Question 16

Which of the following best describes the difference between acute, latent, and chronic viral infections?

Accepted Answer

Acute infections have rapid onset and resolution, latent infections remain dormant with possible reactivation, and chronic infections persist with ongoing viral replication.

Question 17

Which of the following best explains why viruses evolve rapidly?

Accepted Answer

They have high mutation rates, rapid replication cycles, large population sizes, and can undergo recombination or reassortment.

Question 18

During translation in eukaryotic cells, which of the following must occur before translation can begin?

Accepted Answer

The mRNA must be exported from the nucleus to the cytoplasm.

Question 19

Which of the following best describes the function of viral spikes?

Accepted Answer

They mediate attachment to specific host cell receptors, determining host range and tropism.

Question 20

A bacteriophage infects a bacterial cell and integrates its genome into the host chromosome, remaining dormant until induced to enter the lytic cycle. This integrated viral genome is called:

Accepted Answer

Prophage

Comprehensive Microbiology Study Guide: Biomolecules, Genetics, and Virology

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