List the three main steps of aerobic cellular respiration. Which of these steps yields (by far) the most ATP?
Here are two:
Step One: Glucose enters the cell (insulin) and is split into 2 smaller 3 Carbon atoms called pyruvate. Total yield - 2 ATP
Step Two: Pyruvate goes to mitochondria and processed in the Krebs Cycle. Yield = 24 ATP.
The three main steps of aerobic cellular respiration are:
1. Glycolysis: In this step, glucose is broken down into two molecules of pyruvate. This process occurs in the cytoplasm of the cell and generates a small amount of ATP.
2. Krebs Cycle (also known as the Citric Acid Cycle or the TCA cycle): In this step, the pyruvate molecules produced in glycolysis are further broken down in the mitochondria. This cycle releases carbon dioxide and produces high-energy molecules like NADH and FADH2, which carry electrons to the next step.
3. Electron Transport Chain (ETC): This is the final step of aerobic cellular respiration, where the electrons from NADH and FADH2 are passed along a series of protein complexes embedded in the inner mitochondrial membrane. This process generates a large amount of ATP through oxidative phosphorylation.
Out of these three steps, the ETC yields the most ATP. During the electron transport chain process, each NADH molecule can produce around 3 ATP molecules, and each FADH2 molecule can produce around 2 ATP molecules. Therefore, the ETC has the potential to generate a significantly larger amount of ATP compared to the other steps of aerobic cellular respiration. The exact ATP yield can vary, but in general, it can produce around 28-32 ATP molecules through oxidative phosphorylation.