what is the meaning of kerb's cycle
Answers
The Krebs Cycle describes how living cells generate the energy used by the body. It is associated with the process of aerobic respiration which, in animal cells, refers to the cellular conversion of one substance to another substance. Most commonly, this transformation refers to changing adenosine diphosphate (ADP) to adenosine triphosphate (ATP).
In simplest terms, the Krebs Cycle results in adenosine triphosphate (ATP).
In more detailed terms, the Krebs Cycle produces carbon dioxide (CO2), nicotinamide-adenine-dinucleotide (NADH), and flavin-adenine-dinucleotide (FADH2), as well as a small amount of ATP.
Krebs Cycle Steps
Before beginning the Krebs Cycle, pyruvic acid, a substance commonly found in fruits, undergoes a process called glycolysis, in which it is either converted into a carbohydrate or stored in fat cells. In technical terms, this carbohydrate is called acetyl-coenzyme A (acetyl-CoA). It is acetyl-CoA that undergoes the Krebs Cycle.
Acetyl-CoA combines with a molecule called oxaloacetic acid. Together, acetyl-CoA and oxaloacetic acid form what is commonly known as citric acid.
Acetyl-CoA loses its carbon atoms when combining with oxaloacetic acid. The lost carbon atoms from acetyl-CoA combine with oxygen and create CO2 molecules. These molecules are the first products of the Krebs Cycle. They are identical to those the catalysts, or initiators of glycolysis, and prepare the body to undergo glycolysis again.
Citric acid undergoes a series of reactions that change its molecular shape. During these reactions, citric acid releases hydrogen (H) molecules. These H molecules readily attach to two other molecules, nicotinamide-adenine-dinucleotide (NAD) and flavin-adenine-dinucleotide (FAD), creating NADH and the FADH2. These are the second products of the Krebs Cycle. They assist in electron transport.
The reactions that create NADH and FADH2 usually release ATP. While technically a “waste” product, ATP is nonetheless a product of the Krebs Cycle.
The acetyl-CoA eventually breaks completely down, leaving only NADH, FADH2, ATP, and oxaloacetic acid. Oxaloacetic acid is final product of the Krebs Cycle. Like CO2, it prepared the body to undergo the Krebs Cycle a second time.
The sequence of reaction by which most living cell generate energy