Question

What are th phases of glycolysis? Please describe the steps of each phase .

Answer 1

Glycolsis is the aerobic metabolic process that breaks down a single molecule of glucose into two molecules of pyruvic acid. It is broken down into two main phase

Energy requiring and energy releasing phase

Over all it has ten steps. The process takes place in cytosol.

In the first phase which is the energy requiring phase few molecules of glucose gets rearranged and two phosphate gets attached to it, making the modified sugar - fructose - 1,6 - buphisohate. This sugar is unstable and thereby allows the molecule to split into half and forming two phosphate having three carbon sugars. Since the phosphates in there steps come from atp so 2 molecules of atp gets used up. The three carbon sugar which are formed are different from each other. Out of these only glyceraldehyde-3-phosphate is able to enter the next step. However dhap gets easily converted into the favourable one and thus finishes the pathway at the end.

Next phase is the energy releasing phase. Here all the 3carbon sugars gets converted into another 3 carbon molecules, pyruvate through a series of reactions. In these reactions one nadh molecule and two atp molecules are formed. Also this phase takes place twice. Once both the 2 3-carbon sugars and makes four atp as well as two nadh.each step of glycolysis is catalysed by its own enzyme. And the most important enzyme is the phoshofructokinase. It catalyzes formation of 2-phosphate sugar molecule, fructose- 1,6-bisphosphate. Overall it has been observed that glycolysis converts 1six carbon molecule into two 3-carbon molecules of pyruvate. So the product of this process are 2atp molecules and two nadh molecules.