Question

How many TCA cycles are required during the complete oxidation of 2 sucrose?

Answer 1

The citric acid cycle (CAC) – also known as the TCA cycle (tricarboxylic acid cycle) or the Krebs cycle – is a set of chemical events that release energy by oxidising acetyl-CoA generated from carbs, lipids, and proteins. Organisms that respire (as opposed to ferment) use the TCA cycle to create energy, whether through anaerobic or aerobic respiration.

Complete answer:
Sucrose is a six-carbon disaccharide made up of glucose and fructose. In glycolysis, one glucose molecule is broken down into two pyruvic acid molecules (3 carbons), which are then decarboxylated to form two acetyl CoA molecules, which enter the TCA cycle. Because two molecules of glucose require two rounds of the TCA cycle to complete oxidation, two molecules of sucrose will take eight rounds of the TCA cycle to complete oxidation.

The cycle produces amino acid precursors as well as the reducing agent NADH, which are employed in a variety of subsequent processes. Its key role in numerous metabolic pathways shows that it was one of metabolism's early components and may have evolved abiogenically. Despite the fact that it is regarded as a 'cycle,' metabolites do not have to follow a single path; at least three stages of the citric acid cycle have been identified.

The name of this metabolic pathway comes from the citric acid (a tricarboxylic acid that is commonly referred to as citrate since the ionised form predominates at physiological pH that is consumed and subsequently regenerated by this series of events. The cycle absorbs acetate (in the form of acetyl-CoA) and water before converting $NAD^+$ to NADH and emitting $CO_2$.

The citric acid cycle produces NADH, which is then fed into the oxidative phosphorylation (electron transport) pathway. The oxidation of foods to produce usable chemical energy in the form of ATP is the end outcome of these two closely related mechanisms.

The citric acid cycle takes place in the matrix of the mitochondria in eukaryotic cells. The citric acid cycle reaction sequence is executed in the cytosol in prokaryotic cells without mitochondria, such as bacteria, with the proton gradient for ATP synthesis being across the cell's surface (plasma membrane) rather than the inner membrane of the mitochondrion. The TCA cycle produces three NADH, one $FADH_2$, and one GTP as a total yield of energy-containing molecules.

Note:
The Krebs cycle is a process that occurs in the One of the most significant reaction sequences in biochemistry is the Krebs cycle, commonly known as the citric acid cycle or the tricarboxylic acid cycle. This series of processes is not only responsible for the majority of the energy requirements of sophisticated organisms. The Krebs cycle is the cycle of chemical reactions that are the major source of energy in living organisms.