● The `color{Brown}"TCA cycle"` starts with the `color{violet}"condensation of acetyl group"` with `color{violet}"oxaloacetic acid (OAA)"` and water to yield `color{violet}"citric acid"`.
● The reaction is catalysed by the `color{violet}"enzyme citrate synthase"` and a `color{violet}"molecule of CoA"` is released.
● `color{violet}"Citrate"` is then isomerised to `color{violet}"isocitrate"`.
● It is followed by `color{violet}"two successive steps"` of `color{violet}"decarboxylation"`, leading to the formation of `color{violet}"α-ketoglutaric acid"` and then `color{violet}"succinyl-CoA"`.
● In the `color{violet}"remaining steps"` of citric acid cycle, `color{violet}"succinyl-CoA"` is oxidised to `color{violet}"OAA"` allowing the cycle to continue.
● During the conversion of `color{violet}"succinyl-CoA to succinic acid"` a molecule of `color{violet}"GTP"` is synthesised.
● This is a `color{Brown}"substrate level phosphorylation"`.
● In a `color{violet}"coupled reaction GTP"` is converted to `color{violet}"GDP"` with the simultaneous synthesis of `color{violet}"ATP from ADP."`
● Also there are `color{violet}"three points"` in the cycle where `NAD_+` is `color{violet}"reduced"` to `NADH` + `H^+` and one point where `FAD^+` is reduced to `FADH_2`.
● The continued `color{violet}"oxidation of acetic acid"` via the TCA cycle requires the continued replenishment of `color{violet}"oxaloacetic acid"`, the first member of the cycle.
● In addition it also `color{violet}"requires regeneration"` of `NAD^+` and `FAD^+` from `NADH` and `FADH_2` respectively.
● The `color{Brown}"summary equation"` for this phase of respiration may be written as follows:
● We have till now seen that `color{violet}"glucose has been broken down"` to release `CO_2` and `color{violet}"eight molecules"` of `NADH` + `H_+`; `color{violet}"two"` of `FADH_2` have been synthesised besides just `color{violet}"two molecules of ATP."`
● The `color{Brown}"TCA cycle"` starts with the `color{violet}"condensation of acetyl group"` with `color{violet}"oxaloacetic acid (OAA)"` and water to yield `color{violet}"citric acid"`.
● The reaction is catalysed by the `color{violet}"enzyme citrate synthase"` and a `color{violet}"molecule of CoA"` is released.
● `color{violet}"Citrate"` is then isomerised to `color{violet}"isocitrate"`.
● It is followed by `color{violet}"two successive steps"` of `color{violet}"decarboxylation"`, leading to the formation of `color{violet}"α-ketoglutaric acid"` and then `color{violet}"succinyl-CoA"`.
● In the `color{violet}"remaining steps"` of citric acid cycle, `color{violet}"succinyl-CoA"` is oxidised to `color{violet}"OAA"` allowing the cycle to continue.
● During the conversion of `color{violet}"succinyl-CoA to succinic acid"` a molecule of `color{violet}"GTP"` is synthesised.
● This is a `color{Brown}"substrate level phosphorylation"`.
● In a `color{violet}"coupled reaction GTP"` is converted to `color{violet}"GDP"` with the simultaneous synthesis of `color{violet}"ATP from ADP."`
● Also there are `color{violet}"three points"` in the cycle where `NAD_+` is `color{violet}"reduced"` to `NADH` + `H^+` and one point where `FAD^+` is reduced to `FADH_2`.
● The continued `color{violet}"oxidation of acetic acid"` via the TCA cycle requires the continued replenishment of `color{violet}"oxaloacetic acid"`, the first member of the cycle.
● In addition it also `color{violet}"requires regeneration"` of `NAD^+` and `FAD^+` from `NADH` and `FADH_2` respectively.
● The `color{Brown}"summary equation"` for this phase of respiration may be written as follows:
● We have till now seen that `color{violet}"glucose has been broken down"` to release `CO_2` and `color{violet}"eight molecules"` of `NADH` + `H_+`; `color{violet}"two"` of `FADH_2` have been synthesised besides just `color{violet}"two molecules of ATP."`