Question

1. If one glucose molecule enters into glycolysis and proceeds through the PDC and through the citric acid cycle, how many NADH molecules are generated in these reactions?

2. If one glucose molecule enters into glycolysis and proceeds through the PDC and through the citric acid cycle, how many FADH₂ molecules (that can be used directly by the ETC) are generated in these reactions?

3. If one glucose molecule enters into glycolysis and proceeds through the PDC and through the citric acid cycle, how many CO₂ molecules are released in these reactions?

Answer 1

1. During glycolysis two NADH+ is produced when 3-phosphoglyceraldehyde is converted to 1, 3-bisphosphoglycerate. in citric acid cycle When Pyruvate is converted into Acetyl coenzyme A, one NADH+ is produced. When Citric acid is converted into α-ketoglutaric acid one more NADH+ is produced. One NADH+ is produced during the conversion of α-ketoglutaric acid to Succinic acid. While converting Malic acid into Oxaloacetic acid one more NADH+ is produced. So during citric acid cycle total no of NADH+ is 4. But two cycles are required per glucose molecule. So total sum is 8.

Total number of NADH+ at the end of citric acid cycle is 8+2=10

2. one FAD+ is reduced to FADH2 in citric acid cycle where Succinic acid is converted to Malic acid. Since two cycles are required per glucose molecule.so effective number is two

3. 3 CO2 is produced in citric acid cycle during the steps

1. pyruvate is converted in to Acetyl coenzyme A

2. citric acid is converted to α-ketoglutaric acid

3. α-ketoglutaric acid is converted into Succinic acid

Since two cycles are required per glucose molecule. so effective number of CO2 molecule is six