G . breakdown of glycogen to glucose 2. breakdown of glucose to pyruvate 3. synthesis of glucose from pyruvate 4. synthesis of glycogen from glucose Match the following pathways with the correct definition. A. gluconeogenesis B. glycogenolysis C. glycolysis D. glycogen synthesis 1. breakdown of glycogen to glucose 2. breakdown of glucose to pyruvate 3. synthesis of glucose from pyruvate 4. synthesis of glycogen from glucose A-3, B-1, C-2, D-4 A-3, B-2, C-2, D-4 A-4, B-2, C-1, D-3 A-4, B-1, C-2, D-3

A-3, B-1, C-2, D-4

Explanation:

1. breakdown of glycogen to glucose:   B. glycogenolysis

2. breakdown of glucose to pyruvate:  C. glycolysis

3. synthesis of glucose from pyruvate: A. gluconeogenesis

4. synthesis of glycogen from glucose: D. glycogen synthesis

Glycogenolysis:

The process by which glycogen which is stored in the liver is broken down into glucose when ever body needs energy during fasting is known as glycogenolysis.

Glycolysis:

It is first pathway of cellular respiration. In this pathway, glucose which is a 6 carbon compound is broken down into pyruvate which is a 3 carbon compound. Once pyruvate is obtained, based on whether it is aerobic or anaerobic respiration this pyruvate molecule is used to generate energy. If the organism is aerobic then pyruvate enters TCA cycle and then undergo oxidative phosphorylation. But if the organism is anaerobic then pyruvate undergoes fermentation.

Gluconeogenesis:

During gluconeogenesis, glucose is synthesized from bio-molecules other than carbohydrates. Other molecules can be lipids or proteins/amino acids but not nucleic acids (DNA & RNA).

For example: We can regenerate glucose from an amino acid named as alanine. Alanine is first converted into pyruvate by the process of transamination. Once pyruvate has been obtained, it can be converted into glucose again by the process of gluconeogenesis. In short we can say that gluconeogenesis is reverse of glycolysis.

Glycogen synthesis:

After digestion of carbohydrates our body, we gets glucose in abundance. Out of which some amount of glucose is used instantly in the body while rest of the glucose is converted into glycogen and is stored in liver for future use. The process of conversion of glucose into glycogen is named as glycogen synthesis.