Question

Explain the major steps of Glycolysis. Why does this process occur in a cell?

Answer 1

Hint: We all are aware that the cells of our body respire to get energy. This is termed as cellular respiration. Glycolysis is defined as the process by which the cells in our body break the glucose to release energy. The glucose is broken and catabolism down into pyruvate and energy is released in the form of ATP.

Complete answer:
To know the correct answer to the question, we must have knowledge of every step involved in Glycolysis. Glycolysis starts with the conversion of glucose into glucose 6-phosphate which is catalysed by the well-known enzyme hexokinase. This reaction occurs in the presence of ATP. This glucose 6-phosphate formed is now isomerized to fructose 6-phosphate. This then undergoes phosphorylation to form fructose 1,6- diphosphate with the help of ATP and the enzyme kinase.

Fructose 1,6-diphosphate is then broken down into two 3- C containing compounds that are 3 phosphoglyceraldehyde and dihydroxyacetone phosphate. 3-phosphoglyceraldehyde converted into 1,3- diphosphoglyceric acid. At the same time the reduction of $NAD^+$ to $NADH_+$ $H^+$ takes place.
1,3-diphosphoglyceric acid then converted to 3 phosphoglyceric acid which then changes into 2 phosphoglyceric acid.

Next step is the presence of a dehydration reaction. One water molecule gets removed from 2 phosphoglyceric acids. This leads to the formation of 2 phosphoenol pyruvic acid. Lastly, this phosphoenol pyruvic acid gets changed into pyruvic acid in the presence of the enzyme pyruvate kinase.

Glycolysis takes place in the cytosol of the cell cytoplasm because the glucose and other related enzymes needed for the glycolytic pathway can be easily found there in high concentration. The cytoplasm can be defined as a thick solution that fills each cell and is enclosed by the cell wall. It is mainly composed of water, salts, and protein.

Note: Here it must be important to note that the glycolysis occurs in the cytoplasm. It is a common process in both aerobic and anaerobic respiration because it takes place without utilizing oxygen. The pyruvate that gets developed as the end product now goes into the Kreb Cycle which takes place in the mitochondria.