12. Microbial Metabolism

Where specifically does the most significant production of ATP occur in prokaryotic and eukaryotic cells?

Why do human cells require oxygen? Select all relevant statements.

a. To carry out glycolysis

b. To carry out fermentation

c. To carry out cellular respiration

d. To oxidize fats

e. To carry out substrate-level phosphorylation

f. To carry out oxidative phosphorylation

g. To carry out photophosphorylation

Label the diagram below to indicate acetyl-CoA, electron transport chain, FADH2, fermentation, glycolysis, citric acid cycle, NADH, and respiration. Indicate the net number of molecules of ATP that could be synthesized at each stage during bacterial respiration of one molecule of glucose.

Water is one of the products of aerobic cellular respiration. What is the source of the oxygen atom utilized to create the water molecules?

a) Carbon dioxide (CO₂).

b) Glucose (C₆H₁₂O₆).

c) Oxygen gas (O₂).

d) Pyruvate (C₃H₃O₃^–).

Label the mitochondrion to indicate the location of glycolysis, the citric acid cycle, and electron transport chains.

The final electron acceptor in aerobic respiration is ________.

Through the first three stages of cellular respiration only 4 ATP molecules have been produced from the initial glucose molecule. In which of the products of these stages is the potential energy to produce more ATP molecules stored?

a) The 6 molecules of CO₂.

b) The H⁺ ions produced.

c) The 10 NADH and 2 FADH₂ molecules.

d) The 4 molecules of ATP.

Which of the following compounds has the greatest amount of energy for a cell?

a. CO₂

b. ATP

c. glucose

d. O₂

e. lactic acid

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C₆H₁₂O₆) through the process of aerobic cellular respiration?

a) 4.

b) 2.

c) 26-34.

d) 30-38.

Why do we breathe oxygen and give off carbon dioxide?

Under ideal conditions, the complete aerobic oxidation of one molecule of glucose by a bacterium allows a net gain of how many ATP molecules?

a. 2

b. 4

c. 38

d. 0

Rank the following from the most ATP that could be made to the least ATP that could be made:

a. 1 glucose molecule processed via a fermentation pathway (consider that glycolysis is the first stage of the process)

b. A lipid made of glycerol and three 10-carbon fatty acid chains entering cellular respiration

c. 1 glucose molecule entering the Entner–Doudoroff pathway

d. 1 glucose molecule entering cellular respiration

Complete the following chart:

The main coenzymes that carry electrons in catabolic pathways are _______ and ________.