Question 1

Which of the following best defines microbial growth?

Accepted Answer

An increase in the number of microbial cells.

Question 2

A microorganism that uses light as its energy source and carbon dioxide as its carbon source is classified as which of the following?

Accepted Answer

Photoautotroph

Question 3

Which type of microorganism would most likely be found thriving in a hot spring at 70°C?

Accepted Answer

Thermophile

Question 4

A bacterium is placed in a hypertonic solution. What is the most likely effect on the cell?

Accepted Answer

The cell will lose water and undergo plasmolysis.

Question 5

Which of the following best describes an obligate aerobe?

Accepted Answer

A microorganism that requires oxygen for growth.

Question 6

Which of the following is an example of a direct method for measuring microbial growth?

Accepted Answer

Counting colonies on an agar plate.

Question 7

During which phase of the bacterial growth curve do cells divide at their maximum rate?

Accepted Answer

Log (exponential) phase

Question 8

A microbiologist wants to isolate a pure culture from a mixed sample. Which method is most appropriate?

Accepted Answer

Streak plate method

Question 9

Which of the following best describes selective media?

Accepted Answer

Media that inhibits the growth of some microorganisms while allowing others to grow.

Question 10

Which of the following statements about catabolic and anabolic pathways is correct?

Accepted Answer

Catabolic pathways provide energy and building blocks for anabolic reactions.

Question 11

Where does glycolysis occur in prokaryotic cells, and what is the net gain of ATP per glucose molecule?

Accepted Answer

In the cytoplasm; 2 ATP

Question 12

Which of the following equations correctly represents an oxidation-reduction (redox) reaction?

Accepted Answer

$$ \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \rightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} $$

Question 13

Which process is responsible for the light-independent reactions of photosynthesis in microorganisms?

Accepted Answer

Calvin-Benson cycle

Question 14

A patient with muscle cramps after intense exercise is experiencing the effects of which microbial metabolic process?

Accepted Answer

Fermentation

Question 15

In which part of the cell is the majority of ATP generated during aerobic respiration in prokaryotes?

Accepted Answer

Plasma membrane

Question 16

Which of the following best describes the role of enzymes in microbial metabolism?

Accepted Answer

They act as catalysts to speed up biochemical reactions.

Question 17

A microbiologist is using MacConkey agar to isolate bacteria from a stool sample. Which property of MacConkey agar is being utilized?

Accepted Answer

It is a differential medium that distinguishes lactose fermenters from non-fermenters.

Question 18

Which of the following best explains why obligate anaerobes are killed by oxygen?

Accepted Answer

They lack enzymes such as superoxide dismutase and catalase to detoxify reactive oxygen species.

Question 19

A researcher wants to estimate the number of viable bacteria in a water sample. Which method should they use?

Accepted Answer

Plate count method

Question 20

Which of the following best describes the relationship between anabolic and catabolic reactions in microbial cells?

Accepted Answer

Catabolic reactions provide the energy and precursors needed for anabolic reactions.

Microbiology Exam 2 Study Guidance

Study Guide - Practice Questions