Question 1

Which of the following best describes the relationship between catabolism and anabolism in cellular metabolism?

Accepted Answer

Catabolism breaks down molecules to release energy, which is then used by anabolism to build macromolecules.

Question 2

In the redox reaction $$\mathrm{C_6H_{12}O_6$ + 6\ O_2$ \rightarrow 6\ CO_2$ + 6\ H_2O}$$, which molecule is oxidized and which is reduced?

Accepted Answer

Glucose is oxidized and oxygen is reduced.

Question 3

Which of the following statements about NAD+/NADH is correct?

Accepted Answer

NADH donates electrons to become NAD+ during catabolic reactions.

Question 4

During glycolysis, which step involves substrate-level phosphorylation?

Accepted Answer

The conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate.

Question 5

Which of the following best explains why fermentation yields less ATP than respiration?

Accepted Answer

Fermentation does not fully oxidize glucose to CO2, so less energy is extracted.

Question 6

Which of the following is a key feature of oxidative phosphorylation?

Accepted Answer

ATP is generated by ATP synthase using a proton motive force across a membrane.

Question 7

A bacterium is growing anaerobically and produces lactic acid as a major waste product. Which pathway is it most likely using?

Accepted Answer

Homolactic fermentation

Question 8

Which of the following is a correct description of the role of electron carriers in metabolism?

Accepted Answer

Electron carriers transfer electrons from donors to acceptors, facilitating redox reactions.

Question 9

Which of the following is a long-term energy storage compound in prokaryotes?

Accepted Answer

Poly-β-hydroxybutyrate

Question 10

A microorganism is capable of using inorganic compounds as an energy source and CO2 as a carbon source. What is its nutritional classification?

Accepted Answer

Chemolithoautotroph

Question 11

Which of the following best describes the function of ATP synthase?

Accepted Answer

It uses the energy from a proton gradient to synthesize ATP from ADP and Pi.

Question 12

In the electron transport chain, which of the following is the primary function of cytochromes?

Accepted Answer

To transfer electrons via their iron-containing heme groups.

Question 13

Which of the following is true regarding the Calvin-Benson cycle?

Accepted Answer

It fixes CO2 into organic molecules using ATP and NADPH.

Question 14

Which of the following statements about methanogenesis is correct?

Accepted Answer

Methanogenesis uses CO2 as an electron acceptor and H2 as a major electron donor.

Question 15

A cell is using nitrate as a terminal electron acceptor in the absence of oxygen. This process is best described as:

Accepted Answer

Anaerobic respiration

Question 16

Which of the following best explains why the electron transport chain is essential for oxidative phosphorylation?

Accepted Answer

It creates a proton gradient across the membrane, which drives ATP synthesis by ATP synthase.

Question 17

Which of the following is a distinguishing feature of anoxygenic photosynthesis?

Accepted Answer

It uses electron donors such as H2S and does not produce oxygen.

Question 18

A microorganism is found to use the Wood–Ljungdahl pathway for CO2 fixation. Which of the following is most likely true about this organism?

Accepted Answer

It is an acetogen capable of growing autotrophically using H2 and CO2.

Question 19

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

Accepted Answer

It is a cooperative relationship where two organisms degrade a compound together, often with one consuming the other's waste products.

Microbial Metabolism: Electron Flow and Energy Production

Study Guide - Practice Questions