Question 1

Which of the following best describes the difference between catabolic and anabolic reactions in microbial metabolism?

Accepted Answer

Catabolic reactions break down larger molecules into smaller ones, releasing energy; anabolic reactions use energy to build larger molecules from smaller subunits.

Question 2

A bacterium is growing in an environment lacking oxygen but containing nitrate (NO$$_3^-) as a $$terminal electron acceptor. Which metabolic process is it most likely using?

Accepted Answer

Anaerobic respiration

Question 3

Which of the following equations correctly represents the net reaction of aerobic respiration of glucose?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O}$$

Question 4

Which electron carrier is primarily used for biosynthetic (anabolic) reactions in microbial cells?

Accepted Answer

NADPH

Question 5

A mutation in a bacterium prevents the regeneration of NAD$$^+$$ during fermentation. What is the most likely consequence?

Accepted Answer

The cell will accumulate NADH and glycolysis will stop.

Question 6

Which of the following best explains why oxygen is considered a strong terminal electron acceptor in the electron transport chain?

Accepted Answer

Oxygen has a high reduction potential ($$E_0$$'$$), allowing it to accept electrons and release a large amount of free energy.

Question 7

Which of the following is NOT a product of the tricarboxylic acid (TCA) cycle?

Accepted Answer

Pyruvate

Question 8

A microbe is isolated from a salt lake with a water activity ($$a_w) of 0.75. $$Which type of organism is most likely to thrive in this environment?

Accepted Answer

Halobacterium

Question 9

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

Accepted Answer

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

Question 10

Which of the following best describes the role of precursor metabolites in microbial metabolism?

Accepted Answer

They serve as intermediates in catabolic pathways and as building blocks for biosynthesis.

Question 11

A facultative anaerobe such as E. coli is placed in an anaerobic environment with glucose but no alternative electron acceptors. Which metabolic pathway will it primarily use?

Accepted Answer

Fermentation

Question 12

Which of the following trace elements is essential for the function of cytochromes in the electron transport chain?

Accepted Answer

Iron (Fe)

Question 13

Which of the following best describes the function of an enzyme's active site?

Accepted Answer

It is the region where substrate molecules bind and undergo a chemical reaction.

Question 14

Which of the following is a correct formula for calculating the number of cells in a population after a given number of generations?

Accepted Answer

$$N_t = N_0$ 	imes 2^n$$

Question 15

Which of the following is a function of the pentose phosphate pathway in microbial cells?

Accepted Answer

Generation of NADPH and ribose-5-phosphate for biosynthesis

Question 16

A bacterium is found to lack superoxide dismutase and catalase. In which environment would it most likely thrive?

Accepted Answer

Anaerobic sludge

Question 17

Which of the following is a key difference between chemolithotrophs and chemoorganotrophs?

Accepted Answer

Chemolithotrophs use inorganic compounds as energy sources, while chemoorganotrophs use organic compounds.

Question 18

Which of the following best explains why enzymes are necessary for cellular metabolism?

Accepted Answer

They lower the activation energy, allowing reactions to proceed rapidly at cellular temperatures.

Question 19

Which of the following is a real-world application of microbial fermentation?

Accepted Answer

Production of yogurt and cheese

Chapter Three and Four

Study Guide - Practice Questions

Study Guide - Flashcards