Question 1

Which of the following best differentiates catabolism from anabolism in cellular metabolism?

Accepted Answer

Catabolism releases energy by breaking down molecules, whereas anabolism consumes energy to build complex molecules.

Question 2

During a redox reaction, which of the following statements is correct regarding oxidation and reduction?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 3

Which of the following is NOT a mechanism of ATP production in cells?

Accepted Answer

Glycogenolysis

Question 4

What is the primary function of enzymes in metabolism?

Accepted Answer

To lower the activation energy and speed up biochemical reactions

Question 5

Which of the following correctly lists the main reactants and products of glycolysis?

Accepted Answer

Reactant: glucose; Products: 2 pyruvate, 2 ATP, 2 NADH

Question 6

Which pathway is unique in that it produces NADPH and ribose-5-phosphate as major products?

Accepted Answer

Pentose phosphate pathway

Question 7

How does the Entner-Doudoroff pathway differ from glycolysis?

Accepted Answer

It produces 1 ATP, 1 NADH, and 1 NADPH per glucose, whereas glycolysis produces 2 ATP and 2 NADH.

Question 8

In which scenario would a bacterium most likely utilize the pentose phosphate pathway instead of glycolysis?

Accepted Answer

When the cell needs to generate precursors for nucleotide and amino acid synthesis.

Question 9

What is the main purpose of the intermediate step between glycolysis and the Krebs cycle?

Accepted Answer

To convert pyruvate into acetyl-CoA, producing NADH and releasing $CO_2$

Question 10

Which of the following is a product of the Krebs cycle per turn?

Accepted Answer

$2 \ CO_2$, $3 \ NADH$, $1 \ FADH_2$, $1 \ ATP$ (or GTP)

Question 11

Which statement best describes the electron transport chain (ETC) in aerobic respiration?

Accepted Answer

The ETC uses electrons from NADH and FADH2 to pump protons across a membrane, creating a proton gradient.

Question 12

Which of the following best differentiates aerobic from anaerobic respiration?

Accepted Answer

Aerobic respiration uses $O_2$ as the final electron acceptor, while anaerobic respiration uses other inorganic molecules.

Question 13

Which equation best represents the process of chemiosmosis in ATP synthesis?

Accepted Answer

$ADP + P_i \xrightarrow{ATP\ synthase} ATP$

Question 14

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

Accepted Answer

Fermentation uses an organic molecule as the final electron acceptor, while respiration uses an inorganic molecule.

Question 15

Which end products are commonly produced during lactic acid fermentation, and what is their function for bacteria?

Accepted Answer

Lactic acid and ATP; lactic acid regenerates NAD$^+$ for glycolysis.

Question 16

Which structure is directly involved in the light-dependent reactions of photosynthesis?

Accepted Answer

Thylakoid membrane

Question 17

Which of the following is a product of the light-dependent reactions of photosynthesis?

Accepted Answer

NADPH

Question 18

Which of the following best describes the difference between cyclic and noncyclic photophosphorylation?

Accepted Answer

Cyclic photophosphorylation involves only photosystem I and produces ATP but not NADPH or $O_2$.

Question 19

A patient presents with muscle fatigue after intense exercise. Which metabolic pathway is primarily responsible for the accumulation of lactic acid in their muscles?

Accepted Answer

Lactic acid fermentation

Question 20

A bacterium is found to use nitrate ($NO_3^-$) as its final electron acceptor in respiration. Which type of respiration is this, and what is a likely product?

Accepted Answer

Anaerobic respiration; $NO_2^-$

Core Concepts in Microbial Metabolism and Bioenergetics

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