Question 1

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

Accepted Answer

Catabolism involves the breakdown of complex molecules to release energy, while anabolism uses energy to build complex molecules from simpler ones.

Question 2

During aerobic respiration in prokaryotic cells, where does the electron transport chain primarily occur?

Accepted Answer

In the plasma membrane

Question 3

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It directly transfers a phosphate group from a substrate to ADP to form ATP.

Question 4

A patient is diagnosed with a bacterial infection. The bacteria are found to lack both superoxide dismutase and catalase. Which environment would most likely support their growth?

Accepted Answer

An anaerobic environment

Question 5

Which of the following equations correctly represents the calculation for the final number of cells ($$N_f) $$after $$n$$ generations, starting with an initial number of cells ($$N_i$$)?

Accepted Answer

$$N_f = N_i 	imes 2^n$$

Question 6

Which of the following best describes the action of a non-competitive inhibitor on an enzyme?

Accepted Answer

It binds to an allosteric site, changing the enzyme's shape and reducing its activity.

Question 7

A microbiologist is culturing bacteria using a medium that contains only known quantities of pure chemicals. Which type of medium is being used?

Accepted Answer

Chemically defined (synthetic) medium

Question 8

Which of the following is a correct comparison between aerobic respiration, anaerobic respiration, and fermentation in terms of final electron acceptors?

Accepted Answer

Aerobic respiration uses $$O_2$$, anaerobic respiration uses inorganic molecules other than $$O_2 ($$such as $$NO_3$$^-$$ or SO_4$^{2-}$$), and fermentation uses organic molecules.

Question 9

Which of the following best explains why enzymes are sensitive to changes in temperature and pH?

Accepted Answer

Changes in temperature and pH can disrupt hydrogen bonds and ionic interactions, leading to denaturation and loss of enzyme activity.

Question 10

A bacterial culture is growing in a medium with limited glucose. Which phase of the growth curve is most likely being observed if the number of viable cells remains constant?

Accepted Answer

Stationary phase

Question 11

Which of the following statements about feedback inhibition is correct?

Accepted Answer

The end product of a metabolic pathway inhibits an earlier enzyme in the pathway, preventing overproduction.

Question 12

Which of the following is a product of lactic acid fermentation?

Accepted Answer

Lactate

Question 13

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

Accepted Answer

They often serve as coenzymes or precursors for coenzymes in enzymatic reactions.

Question 14

A microbiologist is performing a viable plate count. She plates 0.1 mL of a 1:10,000 dilution and counts 50 colonies. What is the concentration of bacteria in the original sample (in CFU/mL)?

Accepted Answer

$$5 	imes 10^6$ CFU/mL

Question 15

Which of the following statements about the pentose phosphate pathway is correct?

Accepted Answer

It generates NADPH and pentoses for biosynthetic reactions.

Question 16

Which of the following best describes the function of superoxide dismutase in microbial cells?

Accepted Answer

It converts superoxide radicals ($$O_2$$^-$$) into hydrogen peroxide (H_2O_2$) and oxygen.

Question 17

Which of the following is an example of an amphibolic pathway?

Accepted Answer

The Krebs cycle

Question 18

Which of the following best describes a facultative anaerobe?

Accepted Answer

An organism that can grow with or without oxygen, but grows better with oxygen.

Question 19

Which of the following statements about biofilms is correct?

Accepted Answer

Biofilms are communities of microbes attached to a surface and coordinated by quorum sensing.

Question 20

Which of the following best describes the difference between selective and differential media?

Accepted Answer

Selective media inhibit the growth of some organisms while allowing others to grow; differential media distinguish between organisms based on metabolic reactions.

Microbial Metabolism and Growth: Study Guide for MCB 2010C Unit #3

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