How many `NADPH_2` and ATP molecules are produced in a single TCA cycle ?

Options

A. 3 and 1 respectively
B. 2 and 1 respectively
C. 0 and 1 respectively
D. 3 and 2 respectively

Answer

To determine how many NADPH2 and ATP molecules are produced in a single TCA cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the TCA Cycle**: The TCA cycle, also known as the Citric Acid Cycle or Krebs Cycle, is a series of biochemical reactions that take place in the mitochondria. It plays a crucial role in cellular respiration.

2. **Identifying Products of the TCA Cycle**: During one complete turn of the TCA cycle, several key products are generated:
- Carbon dioxide (CO2)
- ATP (Adenosine Triphosphate)
- Reduced forms of NADH (Nicotinamide Adenine Dinucleotide)
- Reduced form of FADH2 (Flavin Adenine Dinucleotide)

3. **Counting ATP Production**: In one cycle of the TCA, **1 ATP** molecule is produced. This ATP can be generated through substrate-level phosphorylation.

4. **Counting NADH Production**: The TCA cycle produces **3 NADH** molecules per cycle. However, it is important to note that NADPH is not produced in the TCA cycle; instead, NADH is produced.

5. **NADPH vs. NADH**: The question specifically asks about NADPH2. It is essential to clarify that NADPH is primarily produced in the Pentose Phosphate Pathway, not in the TCA cycle. Therefore, the TCA cycle does not contribute to NADPH production.

6. **Final Summary**: In summary, during a single TCA cycle:
- **1 ATP** is produced.
- **0 NADPH2** is produced (only NADH is produced).

### Conclusion:
The correct answer is:
- **1 ATP**
- **0 NADPH2**