MUSCLE PHYSIOLOGY

PHYSIOLOGY

MUSCLE ENERGETICS GLYCOLYSIS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
How many pyruvates are used during both turns of the Krebs Cycle?
A
2
B
4
C
6
D
8
Explanation: 

Detailed explanation-1: -The end product of glycolysis is the production of 2 molecules of pyruvate. The cycle mentioned above is always operating in two turns i.e. one cycle per pyruvate molecule. After completion of glycolysis, Krebs cycle and electron transport chain, each glucose molecule yields 38 ATP molecules.

Detailed explanation-2: -Glycolysis, Pyruvate Oxidation and the Krebs Cycle Glycolysis, the process of splitting a six-carbon glucose molecule into two three-carbon pyruvate molecules, is linked to the Krebs cycle. For each glucose molecule respired, the cycle reactions occur twice as two pyruvic acid molecules are formed.

Detailed explanation-3: -Results of the Krebs Cycle After the second turn through the Krebs cycle, the original glucose molecule has been broken down completely. All six of its carbon atoms have combined with oxygen to form carbon dioxide. The energy from its chemical bonds has been stored in a total of 16 energy-carrier molecules.

Detailed explanation-4: -Within the mitochondria, each pyruvate is broken apart and combined with a coenzyme known as CoA to form a 2-carbon molecule, acetyl-CoA, which can enter the Krebs Cycle. A single atom of carbon (per pyruvate) is “lost” as carbon dioxide. The energy released in this breakdown is captured in two NADH molecules.

Detailed explanation-5: -Decarboxylation takes place twice in the TCA cycle forming two carbon dioxide molecules. Since two cycles are required thus, 2 CO2 molecules are released per cycle and in total 4 carbon dioxide molecules are released for one molecule of glucose in the TCA cycle.

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