Question 1

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

Accepted Answer

Catabolism generates energy and reducing power, which are then used by anabolism to build macromolecules.

Question 2

In the acetogenesis pathway of Acetobacterium woodii, what is the net ATP yield per mole of acetate produced from $$4H_2 + 2CO_2$$?

Accepted Answer

0.3 ATP

Question 3

Which of the following is the correct overall stoichiometry for the Calvin-Benson cycle?

Accepted Answer

$$6CO_2 + 12NADPH + 18ATP \rightarrow Fructose-6-phosphate + 12NADP^+ + 18ADP + 17P_i$$

Question 4

During biological nitrogen fixation by nitrogenase, how many ATP molecules are hydrolyzed per molecule of $$N_2$$ reduced?

Accepted Answer

16 ATP

Question 5

Which pathway is primarily responsible for the production of ribose-5-phosphate for nucleotide biosynthesis?

Accepted Answer

Pentose phosphate pathway

Question 6

Which of the following reactions correctly represents the addition of glucose to glycogen using ADP-glucose?

Accepted Answer

$$ADPG + Glycogen \rightarrow ADP + Glycogen-Glucose$$

Question 7

What is the role of uridine diphosphoglucose (UDPG) in polysaccharide biosynthesis?

Accepted Answer

It acts as an activated glucose donor for the synthesis of polysaccharides such as glycogen.

Question 8

Which amino acid family is derived from intermediates of the citric acid cycle?

Accepted Answer

Glutamate family

Question 9

Which enzyme catalyzes the conversion of ribonucleotides to deoxyribonucleotides, and what is the required reducing agent?

Accepted Answer

Ribonucleotide reductase; NADPH

Question 10

Which of the following best describes the biosynthesis of fatty acids in bacteria?

Accepted Answer

Fatty acids are synthesized two carbons at a time, with the growing chain held by an acyl carrier protein (ACP).

Question 11

A bacterium is growing in a medium lacking glucose but rich in pyruvate. Which pathway would it use to synthesize hexose sugars?

Accepted Answer

Gluconeogenesis

Question 12

Which of the following is a precursor for purine nucleotide biosynthesis?

Accepted Answer

Inosinic acid

Question 13

Which of the following statements about ammonia incorporation in bacteria is correct?

Accepted Answer

Glutamate dehydrogenase incorporates ammonia into α-ketoglutarate to form glutamate.

Question 14

Which of the following is NOT a direct product of the pentose phosphate pathway?

Accepted Answer

Pyruvate

Question 15

Which of the following is a key difference between the biosynthesis of purines and pyrimidines?

Accepted Answer

Purines are synthesized on a ribose-phosphate scaffold, while pyrimidines are synthesized as a ring before attachment to ribose-phosphate.

Question 16

Which of the following best explains why the Calvin-Benson cycle requires both ATP and NADPH?

Accepted Answer

ATP provides energy for carbon fixation, while NADPH provides reducing power for the reduction of 3-phosphoglycerate.

Question 17

A mutation in a bacterium prevents the formation of acyl carrier protein (ACP). Which biosynthetic process would be most directly affected?

Accepted Answer

Fatty acid synthesis

Question 18

Which of the following is a correct description of the role of the citric acid cycle in biosynthesis?

Accepted Answer

It provides intermediates that serve as carbon skeletons for amino acid synthesis.

Question 19

Which of the following is a direct precursor for pyrimidine nucleotide biosynthesis?

Accepted Answer

Uridylate

Microbial Biosynthesis and Metabolism: Pathways and Building Blocks

Study Guide - Practice Questions