Question

Contrast the metabolic function of the TCA Cycle with that of the Reverse TCA Cycle using all of the following words correctly:

Answer 1

TCA cycle

Explanation:

TCA or citric acid cycle is an oxidative pathway which occurs in matrix of mitochondria that completely oxidize Acetyl CoA in form of CO2 and produce NADH, FADH2 and GTP

The aim of this cycle is to fulfill the energy demand of cell

In the first step of the cycle, Acetyl CoA combines with a four-carbon acceptor molecule, oxaloacetate, to form a six-carbon molecule called citrate

After a quick rearrangement, this six-carbon molecule releases two of its carbons as carbon dioxide molecules in a pair of similar reactions, producing a molecule of NADH each time

The enzymes that catalyze these reactions are key regulators of the citric acid cycle, speeding it up or slowing it down based on the cell’s energy needs

The remaining four-carbon molecule undergoes a series of additional reactions, first making an ATP molecule—or, in some cells, a similar molecule called GTP—then reducing the electron carrier FAD to FADH2 and finally generating another NADH; This set of reactions regenerates the starting molecule, oxaloacetate, so the cycle can repeat

Overall, one turn of the citric acid cycle releases two carbon dioxide molecules and produces three NADH, one FADH2, one ATP or GTP

The citric acid cycle goes around twice for each molecule of glucose that enters cellular respiration because there are two pyruvates—and thus, two Acetyl CoA made per glucose