By aerobic respiration of 1 molecule of PGAL how many ATP get synthesized considering glycerol phosphate shuttle .

Options

A. 8ATp
B. 2 ATP
C. 19 ATP
D. 36 ATP

Answer

To determine how many ATP are synthesized from the aerobic respiration of one molecule of PGAL (phosphoglyceraldehyde) considering the glycerol phosphate shuttle, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding Glycolysis**:
- PGAL is an intermediate in glycolysis. When one molecule of PGAL is processed through glycolysis, it ultimately leads to the production of 2 molecules of pyruvate.
- During glycolysis, 2 ATP are produced directly and 2 NADH molecules are generated.

2. **Conversion of NADH to ATP**:
- Each NADH produced during glycolysis can yield 2.5 ATP when considering the glycerol phosphate shuttle (as opposed to 3 ATP when using the malate-aspartate shuttle).
- Therefore, from the 2 NADH produced in glycolysis, we get:
\[ 2 \text{ NADH} \times 2.5 \text{ ATP/NADH} = 5 \text{ ATP} \]

3. **Pyruvate to Acetyl-CoA**:
- Each molecule of pyruvate is converted into acetyl-CoA in the mitochondria, and during this conversion, 1 NADH is produced.
- Since we have 2 pyruvate molecules from 1 PGAL, we get:
\[ 2 \text{ NADH} \times 2.5 \text{ ATP/NADH} = 5 \text{ ATP} \]

4. **Krebs Cycle (Citric Acid Cycle)**:
- Each acetyl-CoA enters the Krebs cycle, where it produces:
- 3 NADH (which yields 7.5 ATP)
- 1 FADH2 (which yields 1.5 ATP)
- 1 GTP (which is equivalent to 1 ATP)
- Since we have 2 acetyl-CoA from 1 PGAL, the total ATP from the Krebs cycle will be:
\[ (3 \text{ NADH} \times 2.5 \text{ ATP/NADH}) + (1 \text{ FADH2} \times 1.5 \text{ ATP/FADH2}) + 1 \text{ ATP} = 7.5 + 1.5 + 2 = 11 \text{ ATP} \]

5. **Total ATP Calculation**:
- Now, we can sum up all the ATP produced:
- From glycolysis: 5 ATP
- From pyruvate to acetyl-CoA: 5 ATP
- From Krebs cycle: 11 ATP
- Total ATP = 5 + 5 + 11 = 21 ATP

### Final Answer:
Thus, the total ATP synthesized from the aerobic respiration of one molecule of PGAL, considering the glycerol phosphate shuttle, is **21 ATP**.