MUSCLE PHYSIOLOGY

Detailed explanation-1: -Oxaloacetate is a four-carbon organic molecule produced at the last step of the Krebs cycle (TCA cycle). TCA cycle helps to produce energy-rich molecules such as ATP, NADH, etc., for fulfilling the energy requirements of the cell.

Detailed explanation-2: -At the end of this series of reactions, the four-carbon starting molecule, oxaloacetate, is regenerated, allowing the cycle to begin again.

Detailed explanation-3: -The final step of the Krebs cycle regenerates OAA, the molecule that began the Krebs cycle. This molecule is needed for the next turn through the cycle. Two turns are needed because glycolysis produces two pyruvic acid molecules when it splits glucose.

Detailed explanation-4: -At each turn of the TCA cycle, oxaloacetate is regenerated and can combine with another acetyl-CoA molecule.

Detailed explanation-5: -In the eigth and last step of the citric acid cycle, oxaloacetate is regenerated from malate by malate dehydrogenase so it can once again combine with acetyl CoA and keep the cycle going.