If a molecule of NADH is equivalent to 3 ATP molecules, how many ATP molecules can be produced from 2 glucose molecules by the glycolytic pathway
To calculate the number of ATP molecules produced from 2 glucose molecules by the glycolytic pathway, we need to understand the process of glycolysis and the energy yield at each step.
Glycolysis is the breakdown of glucose to produce energy in the form of ATP. It occurs in the cytoplasm of cells and consists of several enzymatic reactions.
Step 1: Glucose is converted into glucose-6-phosphate (G6P). ATP is used in this step, consuming 1 ATP molecule.
Step 2: G6P is converted into fructose-6-phosphate (F6P).
Step 3: F6P is converted into fructose-1,6-bisphosphate (F1,6BP). ATP is used again, consuming another 1 ATP molecule.
Step 4: F1,6BP is split into two molecules of glyceraldehyde-3-phosphate (G3P).
Step 5: G3P is converted into 1,3-bisphosphoglycerate (1,3BPG). In this step, NAD+ is reduced to NADH.
Step 6: 1,3BPG is converted into 3-phosphoglycerate (3PG). ATP is produced, generating 1 ATP molecule.
Step 7: 3PG is converted into 2-phosphoglycerate (2PG).
Step 8: 2PG is converted into phosphoenolpyruvate (PEP). ATP is produced, generating another 1 ATP molecule.
Step 9: PEP is converted into pyruvate. ATP is produced once again, generating the final 1 ATP molecule.
So, in total, each molecule of glucose going through glycolysis produces 2 ATP molecules (from steps 6, 8, and 9) and 2 NADH molecules (from step 5).
Since 1 molecule of NADH is equivalent to 3 ATP molecules, we need to multiply the number of NADH molecules by 3 to account for their contribution to ATP production.
For 2 glucose molecules, we have 4 NADH molecules (2 NADH per glucose molecule). Multiplying 4 NADH molecules by 3 ATP molecules per NADH gives us a total of 12 ATP molecules.
Therefore, by the glycolytic pathway, 2 glucose molecules can produce a total of 12 ATP molecules.