AP-Micro Microbiology: Microbial Metabolism 3

Question 1

A microorganism produces acetone and butanol as end products of fermentation. Which pathway is it most likely using?

Accepted Answer

Acetone-butanol-ethanol (ABE) fermentation

Answer

Homolactic fermentation

Answer

Alcoholic fermentation

Answer

Mixed acid fermentation

Question 2

Which of the following best describes anoxygenic photosynthesis in purple sulfur bacteria?

Accepted Answer

Uses H2S as electron donor, releases sulfur, no O2 produced

Answer

Uses water as electron donor, releases O2

Answer

Uses CO2 as electron donor, releases glucose

Answer

Uses glucose as electron donor, releases CO2

Question 3

The Entner-Doudoroff (ED) pathway produces which net products per glucose (compared to glycolysis)?

Accepted Answer

1 ATP, 1 NADH, 1 NADPH, 2 pyruvate

Answer

4 ATP, 2 NADH, 2 pyruvate

Answer

2 ATP, 2 NADH, 2 pyruvate

Answer

3 ATP, 3 NADH, 2 pyruvate

Question 4

Catabolite repression in E. coli ensures that glucose is preferentially metabolized over lactose primarily through:

Accepted Answer

Low cAMP levels preventing CAP activation of the lac operon

Answer

High cAMP levels activating the lac operon

Answer

High lactose concentrations inhibiting glucose uptake

Answer

Constitutive expression of β-galactosidase

Question 5

During beta-oxidation of a 16-carbon saturated fatty acid, how many acetyl-CoA molecules are produced?

Accepted Answer

8

Answer

6

Answer

7

Answer

16

Question 6

Which enzyme catalyzes the committed step of the pentose phosphate pathway?

Accepted Answer

Glucose-6-phosphate dehydrogenase

Answer

Phosphofructokinase

Answer

Hexokinase

Answer

Transketolase

Question 7

What type of metabolism does an organism exhibit if it can grow under both aerobic and anaerobic conditions but grows more efficiently with oxygen?

Accepted Answer

Facultative anaerobe

Answer

Obligate aerobe

Answer

Obligate anaerobe

Answer

Microaerophile