Determine the net ATP production?
from one molecule of acetyl CoA through the citric acid cycle and taking the products through oxidative phosphorylation?
To determine the net ATP production from one molecule of acetyl CoA through the citric acid cycle and oxidative phosphorylation, we need to understand the steps involved in both processes.
Acetyl CoA enters the citric acid cycle, also known as the Krebs cycle, which takes place in the mitochondria. In the cycle, acetyl CoA combines with a four-carbon molecule called oxaloacetate to form a six-carbon molecule called citrate.
During the citric acid cycle, the following reactions occur, leading to the production of NADH and FADH2, which are carriers of high-energy electrons:
1. Two molecules of carbon dioxide (CO2) are released.
2. Three molecules of NADH are produced.
3. One molecule of FADH2 is produced.
4. One molecule of ATP through substrate-level phosphorylation is generated.
Next, the NADH and FADH2 produced in the citric acid cycle enter oxidative phosphorylation, which takes place in the inner mitochondrial membrane. Here, these electron carriers transfer their electrons to the electron transport chain (ETC).
The ETC consists of a series of protein complexes that transfer the high-energy electrons from NADH and FADH2 to create a proton gradient across the inner mitochondrial membrane. This proton gradient is then utilized by ATP synthase to produce ATP through a process called chemiosmosis.
The net ATP production from oxidative phosphorylation depends on the number of ATP molecules generated per NADH and FADH2. On average, each NADH molecule produces around 2.5 ATP molecules, while each FADH2 molecule produces around 1.5 ATP molecules.
Now, to determine the net ATP production:
1. For each acetyl CoA molecule entering the citric acid cycle, 3 molecules of NADH are produced. So, 3 NADH x 2.5 ATP (average) = 7.5 ATP.
2. Each acetyl CoA molecule also produces 1 molecule of FADH2. So, 1 FADH2 x 1.5 ATP (average) = 1.5 ATP.
3. The citric acid cycle produces 1 molecule of ATP through substrate-level phosphorylation.
Therefore, the net ATP production from one molecule of acetyl CoA through the citric acid cycle and oxidative phosphorylation is approximately 10 ATP molecules (7.5 from NADH + 1.5 from FADH2 + 1 from substrate-level phosphorylation).