Final answer:
The Krebs cycle is a series of enzymatic reactions that convert acetyl CoA into CO₂, ATP, NADH, and FADH₂. One turn of the cycle yields two CO₂, one ATP (or GTP), three NADH, and one FADH₂. Krebs cycle intermediates also contribute to the synthesis and breakdown of other biological molecules.
Step-by-step explanation:
Krebs Cycle and Energy Production
The Krebs cycle, also known as the citric acid cycle or tricarboxylic acid cycle, is a crucial part of cellular respiration. It converts pyruvate, which is derived from glycolysis, into CO₂, ATP, NADH, and FADH₂. During one turn of the cycle, each two-carbon acetyl CoA molecule is oxidized, resulting in the release of two molecules of CO₂. In the process, one molecule of ATP (or the equivalent in the form of GTP) is produced by substrate-level phosphorylation, three molecules of NADH, and one molecule of FADH₂ are formed. These energy carriers, especially NADH and FADH₂, play vital roles in the electron transport chain, further driving the production of ATP.
As the cycle progresses, the initial six-carbon citrate molecule is systematically converted into five and four-carbon molecules, eventually regenerating oxaloacetate, which can then combine with another acetyl CoA to begin the cycle anew. These steps are catalyzed by various enzymes within the mitochondrial matrix. The intermediates of the Krebs cycle are also utilized for the synthesis and degradation of amino acids and fatty acids, indicating the cycle's central role in the cell's metabolic network.