Question

Write balanced biochemical equations for all the reactions in the catabolism of glucose to two molecules of glyceraldehyde 3-phosphate (the preparatory phase of glycolysis), including the standard free-energy change for each reaction. Then write the overall or net equation for the preparatory phase of glycolysis, with the net standard free-energy change.

Answer 1

Balanced Chemical equations:

the catabolism of glucose takes place in five stages:

1. Glucose + ATP -----> glucose - 6 - phosphate + ADP  G^o = -16.7 KJ/mol

2. glucose - 6 - phosphate -----> fructose - 6 - phosphate G^o = 1.7 KJ/mol

3. fructose - 6 - phosphate + ATP ------> fructose - 1,6 - biphosphate  G^o = 14.2 KJ/mol

4. fructose- 1,6 -biphosphate -----> dihydroxyacetonephosphate + glyceraldehyde-3-phosphate  G^o = 23.8 KJ/mol

5. dihydroxyacetonephosphate -----> glyceraldehyde-3-phosphate G^o = 7.5 KJ/mol

Overall net equation:

Glucose + 2 ATP -----> glyceraldehyde-3-phosphate + 2ADP + 2H⁺G^o = 2.1 KJ/mol