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

Verified step by step guidance

1. Identify the process involved: The complete aerobic oxidation of glucose involves glycolysis, the Krebs cycle, and the electron transport chain.
2. Determine the ATP yield from glycolysis: Glycolysis converts one molecule of glucose into two molecules of pyruvate, yielding a net gain of 2 ATP molecules.
3. Calculate the ATP yield from the Krebs cycle: Each pyruvate enters the Krebs cycle, and since two pyruvates are produced per glucose molecule, the cycle runs twice, generating 2 ATP molecules in total.
4. Assess the ATP production from the electron transport chain: The NADH and FADH2 produced in glycolysis and the Krebs cycle donate electrons to the electron transport chain, resulting in the production of approximately 34 ATP molecules.
5. Sum the ATP yields from all processes: Add the ATP from glycolysis, the Krebs cycle, and the electron transport chain to find the total net gain of ATP molecules from the complete aerobic oxidation of one glucose molecule.

Key Concepts

Aerobic Respiration

Aerobic respiration is a metabolic process in which organisms convert glucose and oxygen into energy, carbon dioxide, and water. This process occurs in the mitochondria of eukaryotic cells and involves glycolysis, the Krebs cycle, and the electron transport chain. It is highly efficient, producing a significant amount of ATP, the energy currency of the cell.

ATP Yield from Glucose

The complete oxidation of one molecule of glucose during aerobic respiration can yield up to 36 to 38 ATP molecules, depending on the efficiency of the electron transport chain and the type of organism. This yield includes ATP produced during glycolysis, the Krebs cycle, and oxidative phosphorylation, making it a crucial concept for understanding energy production in cells.

Substrate-Level Phosphorylation vs. Oxidative Phosphorylation

Substrate-level phosphorylation and oxidative phosphorylation are two mechanisms by which ATP is generated. Substrate-level phosphorylation occurs during glycolysis and the Krebs cycle, producing a small amount of ATP directly. In contrast, oxidative phosphorylation, which occurs in the electron transport chain, generates the majority of ATP through the chemiosmotic gradient created by electron transport, highlighting the efficiency of aerobic respiration.