12. Microbial Metabolism

Which product of the Krebs cycle is also used as a reactant in the Krebs cycle?

a) Citrate.

b) ATP.

c) Acetyl-CoA.

d) Oxaloacetate.

Taking one molecule of glucose through glycolysis, pyruvate oxidation, and the Krebs cycle generates:

a) 6 CO₂, 8 NADH, 2 FADH₂ and 4 ATP.

b) 6 CO₂, 8 NADH, 1 FADH₂ and 2 ATP. 

c)  6 CO₂, 10 NADH, 2 FADH₂ and 4 ATP.  

d) 6 CO₂, 10 NADH, 2 FADH₂ and 2 ATP.

Which of the following reactions produces the most molecules of ATP during aerobic metabolism?

a. Glucose → Glucose 6-phosphate

b. Phosphoenolpyruvic acid → Pyruvic acid

c. Glucose → Pyruvic acid

d. Acetyl CoA → CO₂ + H₂O

e. Succinic acid → Fumaric acid

Which of the following is the best definition of the Krebs cycle?

a. The oxidation of pyruvic acid

b. The way cells produce CO₂

c. A series of chemical reactions in which NADH is produced from the oxidation of pyruvic acid

d. A method of producing ATP by phosphorylating ADP

e. A series of chemical reactions in which ATP is produced from the oxidation of pyruvic acid

_______ is a cyclic series of eight reactions involved in the catabolism of acetyl-CoA that yields eight molecules of NADH and two molecules of FADH₂.