Question

Explain Tricarboxylic Acid cycle?​

Answer 1

Tricarboxylic acid cycle, (TCA cycle), also called Krebs cycle and citric acid cycle, the second stage of cellular respiration, the three-stage process by which living cells break down organic fuel molecules in the presence of oxygen to harvest the energy they need to grow and divide. This metabolic process occurs in most plants, animals, fungi, and many bacteria. In all organisms except bacteria the TCA cycle is carried out in the matrix of intracellular structures called mitochondria.

Answer 2

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Tricarboxylic acid cycle

The TCA cycle starts with the condensation of acetyl group with oxaloacetic acid (OAA) and water to yield citric acid . The reaction is catalysed by the enzyme citrate synthase and a molecule of co2 is released citrate is then isomerized to Isocitrate . It is followed by two successive steps of decarboxylation , leading to the formation of alpha-ketoglutaric acid and then succinyl-CoA. In the remaining steps of citric acid cycle , succinyl-CoA is oxidized to OAA allowing the cyle to continue. During the conversion of succinyl-CoA to succinic acid a molecule of GTP is synthesized. This is a substrate level phosphorylation .In a coupled reaction GTP is converted to GDP with the simultaneous synthesis of ATP from ADP. Also there are three points in the cycle where NAD+ plus is reduced to NADH + H+ and one point where FADH+ is reduced to FADH2..the continued oxidation of acetyl co a via the TCA cycle requires the continued replenishment of oxaloacetic Acid ,the first member of the cycle.