Q: Which of the following equations correctly calculates the standard free energy change ($$\Delta G^0$') $$for a reaction A + B $$\rightarrow C + D$$?

$$\Delta G^0$' = G_f^0$[\text{C} + \text{D}] - G_f^0$[\text{A} + \text{B}]$$

Question 1

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

Accepted Answer

Catabolism breaks down nutrients to release energy, while anabolism synthesizes cell components and requires energy.

Question 2

A microorganism that uses light as an energy source and CO$$_2 as a $$carbon source is classified as a:

Accepted Answer

Photoautotroph

Question 3

Which of the following equations correctly calculates the standard free energy change ($$\Delta G^0$') $$for a reaction A + B $$\rightarrow C + D$$?

Accepted Answer

$$\Delta G^0$' = G_f^0$[	ext{C} + 	ext{D}] - G_f^0$[	ext{A} + 	ext{B}]$$

Question 4

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes are consumed during the reaction and must be resynthesized.

Question 5

In a redox reaction, the electron donor is the substance that:

Accepted Answer

Loses electrons and becomes oxidized.

Question 6

Which of the following best explains why O$$_2 is $$considered the strongest electron acceptor in nature?

Accepted Answer

O$$_2$$ has the most positive reduction potential ($$E_0$$'$$), making it highly likely to accept electrons.

Question 7

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

Accepted Answer

ATP is generated directly from the transfer of a phosphate group to ADP during glycolysis.

Question 8

During fermentation, why must NADH be re-oxidized to NAD$$^+$$?

Accepted Answer

To maintain redox balance and allow glycolysis to continue producing ATP.

Question 9

Which of the following is a key difference between aerobic and anaerobic respiration?

Accepted Answer

Aerobic respiration uses O$$_2 as $$the terminal electron acceptor, while anaerobic respiration uses other compounds such as NO$$_3^- or SO$_4$$^{2-}$$.

Question 10

A bacterium is growing on acetate as its sole carbon source. Which metabolic pathway must be active to replenish oxaloacetate for biosynthesis?

Accepted Answer

Glyoxylate cycle

Question 11

Which of the following best describes the role of the proton motive force (pmf) in oxidative phosphorylation?

Accepted Answer

It drives the synthesis of ATP by ATP synthase as protons flow back across the membrane.

Question 12

Which of the following is a correct equation for the actual free energy change ($$\Delta G) $$under cellular conditions?

Accepted Answer

$$\Delta G = \Delta G^0$' + RT \ln K_{eq}$$

Question 13

Which of the following statements about the electron transport chain (ETC) is TRUE?

Accepted Answer

The ETC is located in the cytoplasmic membrane of prokaryotes and the inner mitochondrial membrane of eukaryotes.

Question 14

Which of the following is a product of the citric acid cycle (per glucose molecule)?

Accepted Answer

6 CO$$_2$$

Question 15

Which of the following best explains why chemolithotrophs are typically autotrophs?

Accepted Answer

They use inorganic molecules as energy sources and CO$$_2 as a $$carbon source.

Question 16

Which of the following statements about fermentation is CORRECT?

Accepted Answer

Fermentation produces ATP only through glycolysis and does not use an electron transport chain.

Question 17

Which of the following is a function of coenzymes in enzymatic reactions?

Accepted Answer

They are loosely bound and can transfer chemical groups between different enzymes.

Question 18

Which of the following is a correct pairing of a macronutrient and its role in microbial nutrition?

Accepted Answer

Nitrogen (N): required for amino acid and nucleotide synthesis

Question 19

Which of the following best describes the main function of the pentose phosphate pathway?

Accepted Answer

To produce 5-carbon sugars for nucleic acid synthesis

Central Metabolism in Microorganisms: Catabolism, Anabolism, and Energy Conservation Unit 3

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