Name: Aerobic Respiration in Plants
Uploaded: 2019-07-19
Duration: 2 min 21 s
Description: Aerobic respiration is complete oxidation of glucose to produce energy in the presence of oxygen in the mitochondria. It is a complex process. Take a look at...

Question

What is 'glycolysis'? Describe various steps involved in glycolysis using schematic representation.

Accepted Answer

The Respiration process is an important metabolic pathway in which an organism obtains energy. The initial phase of respiration is glycolysis. The process during which glucose is converted to pyruvic acid with the help of enzymes is glycolysis. Glycolysis can take place with or without the involvement of oxygen. This process takes place in prokaryotes and eukaryotes i.e., in the cytoplasm of the cell.

Glycolysis can be characterised as a complex process. It occurs through 10 stages. The stages are given below.

Stage 1
In first stage a phosphate group is added to glucose in the cell cytoplasm, by the action of enzyme hexokinase. In this stage a phosphate group is transferred from ATP to glucose forming glucose,6-phosphate.
Stage 2
In the second stage Glucose-6-phosphate is isomerized into fructose,6-phosphate by the enzyme phosphoglucomutase.

Stage 3
In the third stage the other ATP molecule transfers a phosphate group to fructose 6-phosphate and converts it into fructose 1,6-bisphosphate by the action of enzyme phosphofructokinase.

Stage 4
In fourth stage the enzyme aldolase converts fructose 1,6-bisphosphate into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate, which are isomers of each other.

Step 5
In fifth stage triose-phosphate isomerase converts dihydroxyacetone phosphate into glyceraldehyde 3-phosphate which is the substrate in the successive step of glycolysis.

Step 6
This step undergoes two reactions:

In one step the enzyme glyceraldehyde 3-phosphate dehydrogenase transfers 1 hydrogen molecule from glyceraldehyde phosphate to nicotinamide adenine dinucleotide to form NADH + H+.
In another step glyceraldehyde 3-phosphate dehydrogenase adds a phosphate to the oxidized glyceraldehyde phosphate to form 1,3-bisphosphoglycerate.
Step 7
In the seventh stage phosphate is transferred from 1,3-bisphosphoglycerate to ADP to form ATP with the help of phosphoglycerokinase. Thus two molecules of phosphoglycerate and ATP are obtained at the end of this reaction.

Step 8
In the eighth stage the phosphate of both the phosphoglycerate molecules is relocated from the third to the second carbon to yield two molecules of 2-phosphoglycerate by the enzyme phosphoglyceromutase.

Step 9
In the penultimate stage the enzyme enolase removes a water molecule from 2-phosphoglycerate to form phosphoenolpyruvate.

Step 10
In final stage a phosphate from phosphoenolpyruvate is transferred to ADP to form pyruvate and ATP by the action of pyruvate kinase. Two molecules of pyruvate and ATP are obtained as the end products.

Embibe Experts Solutions for Chapter: Respiration, Exercise 1: Maharashtra Board-2019

Embibe Experts Biology Solutions for Exercise - Embibe Experts Solutions for Chapter: Respiration, Exercise 1: Maharashtra Board-2019

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