Final answer:
The Krebs cycle, also known as the citric acid cycle or TCA cycle, is a metabolic pathway turning acetyl-CoA into CO₂ and generating three NADH, one FADH₂, and one ATP (or GTP) for each cycle turn, with the cycle turning twice for each glucose molecule. It is a key component of cellular respiration, vital for energy production and the synthesis of non-essential amino acids.
Step-by-step explanation:
Essential Features of the Krebs Cycle
The Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle, is a critical metabolic pathway that occurs in the inner mitochondrial matrix. The primary molecule fed into the cycle is acetyl-CoA, which is derived from pyruvate that comes from glycolysis. Each turn of the Krebs cycle yields essential molecules: three NADH, one FADH₂, and one ATP (or GTP) by substrate-level phosphorylation. Additionally, two molecules of CO₂ are released. Since one glucose molecule results in two molecules of acetyl-CoA, the Krebs cycle must turn twice to process all the carbon from one glucose molecule.
The Krebs cycle is not only important for energy production but also for the synthesis of non-essential amino acids, making it an amphibolic (both catabolic and anabolic) pathway. The NADH and FADH₂ produced are then used by the electron transport chain to produce a significant amount of ATP.
Notably, the Krebs cycle was proposed by Sir Hans Krebs in 1937 and he was awarded the Nobel Prize in Medicine in 1953 for the discovery of this fundamental biological process.