Question 1

Which of the following best describes microbial growth?

Accepted Answer

An increase in the number of microbial cells.

Question 2

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

Accepted Answer

Photoautotroph

Question 3

Which type of microorganism would most likely thrive in a hot spring with temperatures above 70°C?

Accepted Answer

Thermophile

Question 4

A bacterium is placed in a solution with high salt concentration. Which of the following best describes the effect on the cell?

Accepted Answer

The cell will undergo plasmolysis due to osmotic pressure.

Question 5

Obligate anaerobes are microorganisms that:

Accepted Answer

Are killed by the presence of oxygen.

Question 6

Which method is considered a direct measurement of microbial growth?

Accepted Answer

Counting colonies on an agar plate.

Question 7

During which phase of the bacterial growth curve are cells most susceptible to antibiotics targeting cell wall synthesis?

Accepted Answer

Log (exponential) phase

Question 8

Which technique is best for isolating pure colonies from a mixed culture?

Accepted Answer

Streak plate method

Question 9

Which of the following media is both selective and differential for Gram-negative bacteria?

Accepted Answer

MacConkey agar

Question 10

Which statement best describes a catabolic pathway?

Accepted Answer

It breaks down complex molecules into simpler ones, releasing energy.

Question 11

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

Accepted Answer

In the cytoplasm; net gain of 2 ATP

Question 12

Which of the following best represents an oxidation reaction in microbial metabolism?

Accepted Answer

Loss of electrons from a molecule

Question 13

In photosynthesis, the light-dependent reactions produce which of the following?

Accepted Answer

ATP and NADPH

Question 14

Which metabolic process allows microorganisms to generate energy in the absence of oxygen?

Accepted Answer

Fermentation

Question 15

Where in the cell is the most ATP generated during aerobic respiration?

Accepted Answer

Cell membrane (prokaryotes) or mitochondria (eukaryotes)

Question 16

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

Accepted Answer

Enzymes act as catalysts, speeding up reactions by lowering activation energy.

Question 17

A microbiologist wants to determine the number of viable cells in a sample. Which method should they use?

Accepted Answer

Counting colonies after plating

Question 18

Which equation correctly represents the net ATP yield from glycolysis per glucose molecule?

Accepted Answer

$$	ext{Glucose} ightarrow 2 	ext{Pyruvate} + 2 	ext{ATP} + 2 	ext{NADH}$$

Question 19

A facultative anaerobe is placed in a tube of nutrient broth. Where would you expect most growth?

Accepted Answer

Throughout the tube, but more at the top

Question 20

Which of the following best describes the relationship between anabolic and catabolic pathways?

Accepted Answer

Catabolic pathways provide energy and building blocks for anabolic pathways.

Microbiology Exam 2 Study Guidance

Study Guide - Practice Questions