InterviewSolution
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InterviewSolution
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Question : Describe theprocess occurring in matrixof mitochondria. |
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Answer» Solution :The TCA cycle start with the condensation of acetyl group with oxaloacetic acid (OAA) and water to yieldcitric acid. The REACTION is catalysed by the enzyme citratesynthase and a molecule of CoAis released. `OA A (4C) + "Acetyl "CoA + H_(2) O (2C) underset("Citrate synthatase")to` Citric acid 6C + CoA Citrate is then isomerised to isocitrate. It is followingby two successive steps ofdecarboxylation, leading to theformation of `alpha`-ketoglutaric acidand then succinyl-CoA Citric acid `to`Iso Citrate `to alpha` - ketoglutaric acid Remaining steps of citric acid cycle : Succinyl-Coa is oxidised to OAAallowing the cycleto continue. During the conversion of succinyl-CoAto succinic acid a molecule of GTP is synthesized . This is a substrate levelphosphorylation. Ina coupled reaction GTP is converted to GDPwith thesimultaneoussynthesis of ATPform ADP. `GTP to GDP + Pi to ADP + Pi to ATP` Also there are three points in the cyclewhere `NAD^(+)`is reduced to NADH + `H^(+)`and onepoint where `FAD^(+)`is reduced to `FADH_(2)` .The continued oxidation of acetyl CoAVia theTCA cyclerequiresthe continued replenishmentof oxaloaceticacid It isthe first member of the cycle . INADDITION it alsorequires regeneration of `NAD^(+) and FAD^(+)`from NADH and `FADH_(2)`respectively The summary equation for this phase of respiration may be written as follow : Pyruvic acid `+ 4NAD^(+) + FAD^(+) + 2H_(2) O + ADP + Pi underset("Matrix")overset("Mitochondrial")to ` `3CO_(2) + 4NADH + 4H^(+) + FADH_(2) + ATP` Glucose has been broken down to release `CO_(2)`and eightmolecules of `NADH + H^(+)` , two of `FADH_(2)` have been synthesised besidesjusttwo MOLECULES of ATP in TCAcycle . 
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