Q. The total number of ATP formed in the aerobic respiration from one glucose molecule is:
NTA AbhyasNTA Abhyas 2022
Solution:
The energetics of aerobic respiration is as follows:
ATP Consuming Reactions Phosphorylation-I $Glucose \, + \, ATP \, \rightarrow _{M g^{2 +}}^{H e x o k i n a s e} \, Glucose \, 6-Phosphate \, + \, ADP$ -1 ATP -1 ATP Phosphorylation-II $Fructose \, 6-Phosphate \, + \, ATP \, \rightarrow _{M g^{2 +}}^{P h o s p h o f r u c t o k i n a s e} \, Fructose \, 1,6-Biphosphate$ -1 ATP -1 ATP Net Gain 8 ATP
Energetics of Link reaction Reaction Type Reaction Products of reaction In terms of ATP Dehydrogenation $Pyruvate \, + \, CoA \, + \, NAD^{+} \, \rightarrow _{M g^{+ 2} , \, T P P , \, L i p o i c \, a c i d}^{P y r u v a t e \, d e h y d r o g e n a s e} \, Acetyl \, CoA \, + \, NADH_{2} \, + \, CO_{2}$ 2 x NADH2 6 ATP
Energetics of Kreb's cycle/TCA cycle Reaction Type Reaction Products of reaction In terms of ATP Dehydrogenation-I $Isocitrate \, + \, NAD^{+} \, \rightarrow _{M n^{+ 2}}^{I s o c i t r a t e \, d e h y d r o g e n a s e} \, Oxalosuccinate \, + \, NADH_{2} \, $ 2 x NADH2 6 ATP Oxidative decarboxylation $\alpha -Ketoglutarate \, + \, CoA \, + \, NAD^{+} \, \rightarrow _{M g^{+ 2} , \, T P P , \, L i p o i c \, a c i d}^{\alpha - K e t o g l u t a r a t e \, d e h y d r o g e n a s e} \, Succinyl \, CoA \, + \, NADH_{2} \, + \, CO_{2}$ 2 x NADH2 6 ATP Dehydrogenation III $Succinate \, + \, FAD \, \overset{S u c c i n i c \, d e h y d r o g e n a s e}{ \rightarrow } \, Fumarate \, + \, FADH_{2} \, $ 2 x FADH2 4 ATP Dehydrogenation IV $Malate \, + \, NAD^{+} \, \overset{M a l a t e \, d e h y d r o g e n a s e}{ \rightarrow } \, Oxaloacetate \, + \, NADH_{2} \, $ 2 x NADH2 6 ATP Substrate-level Phosphorylation $Succinyl \, CoA \, + \, GDP \, + \, Pi \, \overset{S u c c i n y l \, C o A \, s y n t h e t a s e / S u c c i n y l \, t h i o k i n a s e}{ \rightarrow } \, Succinate \, + \, GTP \, + \, CoA$ 2 x 1 GTP 2 ATP Net gain 24 ATP Net gain in aerobic respiration (Glycolysis + Link reaction + Kreb's cycle) 8 ATP + 6 ATP + 24 ATP 38 ATP
| Phosphorylation-I | $Glucose \, + \, ATP \, \rightarrow _{M g^{2 +}}^{H e x o k i n a s e} \, Glucose \, 6-Phosphate \, + \, ADP$ | -1 ATP | -1 ATP |
| Phosphorylation-II | $Fructose \, 6-Phosphate \, + \, ATP \, \rightarrow _{M g^{2 +}}^{P h o s p h o f r u c t o k i n a s e} \, Fructose \, 1,6-Biphosphate$ | -1 ATP | -1 ATP |
| Net Gain | 8 ATP |
| Reaction Type | Reaction | Products of reaction | In terms of ATP |
| Dehydrogenation | $Pyruvate \, + \, CoA \, + \, NAD^{+} \, \rightarrow _{M g^{+ 2} , \, T P P , \, L i p o i c \, a c i d}^{P y r u v a t e \, d e h y d r o g e n a s e} \, Acetyl \, CoA \, + \, NADH_{2} \, + \, CO_{2}$ | 2 x NADH2 | 6 ATP |
| Reaction Type | Reaction | Products of reaction | In terms of ATP |
| Dehydrogenation-I | $Isocitrate \, + \, NAD^{+} \, \rightarrow _{M n^{+ 2}}^{I s o c i t r a t e \, d e h y d r o g e n a s e} \, Oxalosuccinate \, + \, NADH_{2} \, $ | 2 x NADH2 | 6 ATP |
| Oxidative decarboxylation | $\alpha -Ketoglutarate \, + \, CoA \, + \, NAD^{+} \, \rightarrow _{M g^{+ 2} , \, T P P , \, L i p o i c \, a c i d}^{\alpha - K e t o g l u t a r a t e \, d e h y d r o g e n a s e} \, Succinyl \, CoA \, + \, NADH_{2} \, + \, CO_{2}$ | 2 x NADH2 | 6 ATP |
| Dehydrogenation III | $Succinate \, + \, FAD \, \overset{S u c c i n i c \, d e h y d r o g e n a s e}{ \rightarrow } \, Fumarate \, + \, FADH_{2} \, $ | 2 x FADH2 | 4 ATP |
| Dehydrogenation IV | $Malate \, + \, NAD^{+} \, \overset{M a l a t e \, d e h y d r o g e n a s e}{ \rightarrow } \, Oxaloacetate \, + \, NADH_{2} \, $ | 2 x NADH2 | 6 ATP |
| Substrate-level Phosphorylation | $Succinyl \, CoA \, + \, GDP \, + \, Pi \, \overset{S u c c i n y l \, C o A \, s y n t h e t a s e / S u c c i n y l \, t h i o k i n a s e}{ \rightarrow } \, Succinate \, + \, GTP \, + \, CoA$ | 2 x 1 GTP | 2 ATP |
| Net gain | 24 ATP | ||
| Net gain in aerobic respiration (Glycolysis + Link reaction + Kreb's cycle) | 8 ATP + 6 ATP + 24 ATP | 38 ATP |