What is the net gain of ATP molecules in Glucolysis ?

Explanation

Balance sheet of ATP production in aerobic oxidation of Glucose.
1) Glycolysis :
1. ATP produced by substrate level phosphorylation Bisphosphoglyceric acid to phosphoglyceric acid : `2 xx 1 = 2 ATP`
phosphoenol pyruvic acid to pyruvic acid : `2 xx 1 = 2 ATP`
ATP consumed : for the phosphorylation of glucose and fructose-6-phosphate: `-2 ATP`
Net gain of ATP : `+ 2 ATP`

2. ATP from NADH generated in glycolysis : G-3-Pto BPGA (2NADH, each worth 2ATP) : `2 xx 2 = 4 ATP`
Total ATP gain from glycolysis in the presence of `O_(2)` : `""^(a)6 ATP`

2) Oxidative decarboxylation of pyruvic acid
Pyruvic acid to acetyl COA
(2-NADH, each worth 3 ATP) : `""^(b) 2 xx 3 = 6 ATP`
3) Krebs cycle
1. ATP produced in substrate level phosphorylation: Succinyl CoA to succinic acid. : `2 xx 1 = 2 ATP`
2. ATP from NADH: Isocitric acid to Oxalosuccinic acid : `2 xx 3 = 6ATP`
a-Ketoglutaric acid to succinyl CoA : `2 xx 3 = 6 ATP`
Malic acid to Oxalocaetic acid : `2 xx 3 = 6 ATP`
3. ATP from `FADH_(2)` :Succinic acid to fumaric acid : `2 xx 2 = 4 ATP`
Total ATP value of krebs cycle: `""^( c)24 ATP`
Net gain of ATP in aerobic respiration per mole glucose (a+b+c) : 36 ATP