How many ATP molecules are produced by aerobic oxidation of one molecules of glucose ?

Options

A. 2
B. 4
C. 38
D. 24

Explanation

To determine how many ATP molecules are produced by the aerobic oxidation of one molecule of glucose, we can follow these steps:

### Step-by-Step Solution:

1. **Glycolysis**:
- The process begins with glycolysis, where one molecule of glucose (a six-carbon molecule) is broken down into two molecules of pyruvate (three-carbon molecules).
- During glycolysis, there is a net gain of 2 ATP molecules and 2 NADH molecules.
- Each NADH can produce approximately 3 ATP when oxidized in the electron transport chain. Therefore, 2 NADH will yield 6 ATP (2 NADH x 3 ATP/NADH).
- Total ATP from glycolysis = 2 ATP (net gain) + 6 ATP (from NADH) = **8 ATP**.

2. **Krebs Cycle (Citric Acid Cycle)**:
- Each pyruvate molecule enters the Krebs cycle as acetyl CoA. Since glycolysis produces 2 pyruvate molecules from one glucose, the Krebs cycle will turn twice.
- For each turn of the Krebs cycle, the following ATP equivalents are produced:
- 3 NADH (3 x 3 ATP = 9 ATP)
- 1 FADH2 (1 x 2 ATP = 2 ATP)
- 1 GTP (equivalent to 1 ATP)
- Therefore, for one turn of the Krebs cycle, the total ATP produced = 9 ATP + 2 ATP + 1 ATP = **12 ATP**.
- Since there are 2 turns of the Krebs cycle (one for each pyruvate), the total ATP from the Krebs cycle = 12 ATP x 2 = **24 ATP**.

3. **Total ATP Production**:
- Now, we add the ATP produced from glycolysis and the Krebs cycle:
- Total ATP = ATP from glycolysis + ATP from Krebs cycle = 8 ATP + 24 ATP = **32 ATP**.

4. **Final Calculation**:
- However, in some calculations, it is common to consider the total ATP yield as 36 or 38 ATP due to variations in the efficiency of NADH and FADH2 oxidation in different cell types. But the most accepted value is **30 to 32 ATP** for aerobic respiration of one glucose molecule.

### Conclusion:
The aerobic oxidation of one molecule of glucose produces approximately **30 to 32 ATP molecules**.