What is the Krebs Cycle?
The Krebs Cycle is the third stage of cellular respiration. It is a cyclic metabolic pathway in which cells use pyruvate from glycolysis to produce 3NADH and 1FADH2, 2CO2, and 1 ATP per turn.
NADH and FADH2 are electron carriers. These two molecules are shuttled to the inner mitochondrial membrane to be used by the Electron Transport Chain (more on that later).
The Krebs Cycle occurs in the mitochondrial matrix.
Pyruvate from glycolysis enters the mitochondrion via the pyruvate dehydrogenase complex (PDHC) which is a multienzyme complex located in the outer mitochonrial membrane.
The PDHC compelx converts pyruvate to acetyl-CoA.
Two pyruvates are formed at the end of glycolysis. Therefore,
2Pyruvate -----> 2acetly-CoA + 2 CO2
Remember, the overall equation for cellular respiration is:
C6H12O6 + 6O2 --------> 6CO2 + 6H20 + energy (ATP)
glucose + oxygen -----> carbon dioxide + water + energy
Glycolysis converts the glucose to pyruvate.
Pyruvate is converted to acetyl-CoA yielding two carbon dioxide molecules. The other 4 CO2 are produced during the Krebs Cycle.
No comments:
Post a Comment