$$5'\text{-}TACGGCAT\text{-}3'$$

Question 1

Which of the following best describes the structure and location of a typical bacterial chromosome?

Accepted Answer

It is a single, circular DNA molecule found in the nucleoid region of the cell.

Question 2

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are small, circular DNA molecules that replicate independently of the bacterial chromosome.

Question 3

During DNA replication in bacteria, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 4

If a DNA strand has the sequence 5'-ATGCCGTA-3', what is the complementary DNA strand?

Accepted Answer

$$5'	ext{-}TACGGCAT	ext{-}3'$$

Question 5

Which of the following best describes the central dogma of genetics?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 6

Which of the following is TRUE regarding the lac operon in E. coli?

Accepted Answer

It is induced (turned on) in the presence of lactose and absence of glucose.

Question 7

A point mutation that results in a premature stop codon is called:

Accepted Answer

A nonsense mutation

Question 8

Which of the following best describes transformation in bacteria?

Accepted Answer

Uptake of naked DNA from the environment by a competent cell

Question 9

Which of the following physical methods is used to preserve, rather than kill, microbes?

Accepted Answer

Lyophilization

Question 10

Which of the following is a beta-lactam antibiotic, and what is its primary mode of action?

Accepted Answer

Penicillin; inhibits cell wall synthesis by preventing cross-linking of peptidoglycan

Question 11

Which of the following is a major reason why Gram-negative bacteria are more resistant to certain antibiotics than Gram-positive bacteria?

Accepted Answer

The presence of an outer membrane that restricts drug entry

Question 12

Which of the following best describes a virus in the extracellular state?

Accepted Answer

It consists of a nucleic acid genome surrounded by a protein capsid, and may have an envelope.

Question 13

Which of the following statements about prions is CORRECT?

Accepted Answer

Prions are infectious proteins that cause neurodegenerative diseases.

Question 14

Which of the following is the most common mechanism by which antimicrobial drugs inhibit bacterial cell wall synthesis?

Accepted Answer

Blocking the cross-linking of peptidoglycan chains

Question 15

A patient is prescribed a broad-spectrum antibiotic for a prolonged period. Which of the following is a likely consequence?

Accepted Answer

Disruption of normal microbiota, leading to secondary infections such as Clostridioides difficile

Question 16

Which of the following best describes the difference between narrow-spectrum and broad-spectrum antimicrobial drugs?

Accepted Answer

Narrow-spectrum drugs target specific groups of microbes, while broad-spectrum drugs affect a wide range of microbes.

Question 17

Which of the following is a key difference between the lytic and lysogenic cycles of bacteriophage replication?

Accepted Answer

In the lysogenic cycle, the viral genome integrates into the host genome and can remain dormant.

Question 18

Which of the following best explains why synergism between two antimicrobial drugs can be more effective than using one drug alone?

Accepted Answer

The combined effect of the drugs is greater than the sum of their individual effects.

Question 19

Which of the following is a correct pairing of a physical or chemical method of microbial control with its category?

Accepted Answer

Boiling: Disinfection

Microbial Genetics, Control, and Virology: Step-by-Step Study Guide

Study Guide - Practice Questions