Question 1

Which of the following best explains why viruses are not considered living organisms?

Accepted Answer

Viruses lack a cell membrane and cannot reproduce independently.

Question 2

A virus with a segmented genome infects a host cell simultaneously with another virus of the same species. What process may occur, and what is its significance?

Accepted Answer

Reassortment, which can lead to the emergence of new viral strains with novel properties.

Question 3

Which of the following best describes the difference between antigenic drift and antigenic shift in influenza viruses?

Accepted Answer

Antigenic drift involves small, gradual mutations; antigenic shift involves major changes due to reassortment.

Question 4

During the lytic cycle of a bacteriophage, which step immediately follows the assembly of new viral particles?

Accepted Answer

Release of virions from the host cell.

Question 5

A virus is classified as an oncovirus if it:

Accepted Answer

Can induce uncontrolled cell growth leading to cancer.

Question 6

Which laboratory technique is most useful for quantifying the number of infectious virus particles in a sample?

Accepted Answer

Plaque assay

Question 7

Which of the following best describes prions?

Accepted Answer

Infectious proteins that cause neurodegenerative diseases by inducing abnormal folding of host proteins.

Question 8

A bacterium divides by binary fission every 30 minutes. If you start with 1 cell, how many cells will there be after 3 hours? Use the formula $$N = N_0$ 	imes 2^n$$, where $$n is $$the number of generations.

Accepted Answer

64

Question 9

Which stage of bacterial growth in a closed batch system is characterized by rapid cell division and exponential increase in cell number?

Accepted Answer

Log (exponential) phase

Question 10

A halophile is most likely to thrive in which environment?

Accepted Answer

High salt concentration

Question 11

Which type of microbe would be most likely to grow at refrigerator temperatures?

Accepted Answer

Psychrotroph

Question 12

Which of the following best describes the difference between phototrophs and chemotrophs?

Accepted Answer

Phototrophs use light as an energy source; chemotrophs use chemicals.

Question 13

Which of the following is a direct method for counting microbial cells?

Accepted Answer

Microscopic cell count

Question 14

Which heat treatment is most effective for sterilizing laboratory media?

Accepted Answer

Autoclaving at $$121\ ^\circ \mathrm{C}$$ for 15 minutes

Question 15

Which of the following best defines metabolism?

Accepted Answer

The sum of all chemical reactions in a cell.

Question 16

Which of the following statements about ATP is correct?

Accepted Answer

ATP consists of adenine, ribose, and three phosphate groups.

Question 17

Which molecule is responsible for producing ATP from ADP during cellular respiration?

Accepted Answer

ATP synthase

Question 18

Which step of cellular respiration produces the most ATP?

Accepted Answer

Electron transport chain

Question 19

During fermentation, what is the main goal for the cell?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue.

Question 20

Which of the following is a coupled redox reaction in cellular respiration?

Accepted Answer

NAD$$^+ + 2e$^- + 2H$^+$$ $$\rightarrow$$ NADH + H$$^+$$

Study Guide: Viruses, Microbial Growth, and Metabolism

Study Guide - Practice Questions

Study Guide - Flashcards