Question

What is kreb cycle ?state with reaction.

Answer 1

Krebs cycle (also known as Citric Acid Cycle or Tricarboxylic Acid Cycle) is a step wise cyclic process which is used to oxidize the pyruvate formed during the glycolytic breakdown of glucose into Carbon Dioxide (CO2) and Water (H2O). It also oxidizes acetyl CoA which arises from breakdown of carbohydrate, lipid, and protein. The actual Krebs cycle begins when acetyl –CoA enters into a reaction to form citric Acid. This cycle was discovered by British biochemist Sir Hans Krebs

Answer 2

The Krebs cycle is the middle of the three major steps in cellular respiration, the splitting of a glucose molecule to release energy for cells to use.  The first step is glycolysis a series of reactions that splits the 6 carbon ring of carbon that is glucose.  This occurs in the cytoplasm of the cell.  Only 2 net molecules of ATP are generated along with two 3-carbon molecules.  These enter the mitochondria, go through intermediate reactions releasing of the three carbon atoms in the form carbon dioxide.  These 2-carbon molecules enter the Krebs cycle where a series of reactions break the bonds holding these last two carbon atoms releasing more carbon dioxide - that's what you are exhaling as you read this.  The Krebs cycle generates only 2 more molecules of ATP.  The big payoff is the electron transport chain where 34 ATP molecules are generated.

The Krebs reactions are a cycle because they start and end with the same molecules.