Q: You plate 0.1 mL of a $$10^{-4}$$ dilution and count 50 colonies. What is the concentration of bacteria in the original sample (CFU/mL)?

$$50 \times 10^5$ = 5,000,000$$ CFU/mL

Question 1

Which of the following best describes the role of ATP in the relationship between catabolic and anabolic pathways, as shown in the diagram?

Accepted Answer

ATP acts as an energy currency, storing energy from catabolic reactions and providing it for anabolic reactions.

Question 2

A bacterial cell divides by binary fission. If you start with 1 cell and the generation time is 30 minutes, how many cells will there be after 3 hours?

Accepted Answer

$$2^6 = 64$ cells

Question 3

During which phase of the bacterial growth curve is the rate of cell division equal to the rate of cell death?

Accepted Answer

Stationary phase

Question 4

You plate 0.1 mL of a $$10^{-4}$$ dilution and count 50 colonies. What is the concentration of bacteria in the original sample (CFU/mL)?

Accepted Answer

$$50 	imes 10^5$ = 5,000,000$$ CFU/mL

Question 5

According to the exponential death rate table, if you start with $$1,000,000$$ bacteria and $$90,000$$ die per minute, how many survivors are left after 2 minutes?

Accepted Answer

$$10,000$$

Question 6

Which of the following is NOT a mechanism by which bacteria can resist the effects of antibiotics, as shown in the diagram?

Accepted Answer

Increasing the permeability of the cell wall to antibiotics

Question 7

Which statement best explains the role of ATP in coupling anabolic and catabolic reactions?

Accepted Answer

ATP stores energy from catabolic reactions and releases it for anabolic reactions.

Question 8

Which of the following best describes a holoenzyme?

Accepted Answer

An apoenzyme combined with its cofactor and coenzyme, forming an active enzyme

Question 9

Which of the following factors does NOT directly affect enzyme activity as shown in the graphs?

Accepted Answer

Oxygen concentration

Question 10

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Competitive inhibitors resemble the substrate and bind to the active site.

Question 11

In the redox reaction $$A + B \rightarrow A^+ + B^-$$, which molecule is oxidized and which is reduced?

Accepted Answer

A is oxidized, B is reduced

Question 12

Where does the electron transport chain occur in prokaryotic cells?

Accepted Answer

Plasma membrane

Question 13

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is generated directly by transferring a phosphate group from an organic molecule to ADP.

Question 14

Which of the following is true regarding the stationary phase of bacterial growth?

Accepted Answer

The rate of cell division equals the rate of cell death.

Question 15

Which of the following best describes the difference between catabolism and anabolism?

Accepted Answer

Catabolism releases energy by breaking down molecules, while anabolism uses energy to build complex molecules.

Microbial Metabolism, Growth, and Control: Exam 2 Study Guide

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