Question

Write the overall reaction of glycolysis.

Answer 1

Glycolysis is the first of the cellular respiration's key metabolic pathways to release energy in the form of ATP. Via a series of enzymatic reactions, the six-carbon ring of glucose is cleaved into two three-carbon sugars of pyruvate in two distinct phases. The first step of glycolysis consumes energy, while the second phase completes the conversion to pyruvate and generates ATP and NADH for use by the cell.

Complete answer:
To make glucose $6$-phosphate, a phosphate from the hydrolysis of an ATP molecule is added to glucose, a $6$-carbon sugar.
The glucose $6$-phosphate molecule is split into two isomers: glucose $6$-phosphate and fructose $6$-phosphate.
To form fructose$1$, a second phosphate is added to fructose $6$-phosphate through the hydrolysis of a second molecule of ATP.
The 6-carbon fructose$1$,$6$-biphosphate is broken down into two $3$-carbon molecules of glyceraldehyde $3$-phosphate.
Each glyceraldehyde $3$-phosphate is oxidized and phosphorylated to produce $1$,$3$-diphosphoglycerate with a high-energy phosphate bond (wavy red line) and NADH.
The high-energy phosphate is extracted from the substrate by substrate-level phosphorylation. The high-energy phosphate is extracted from each $1$,$3$-diphosphoglycerate and transferred to ADP, forming ATP and $3$-phosphoglycerate, by substrate-level phosphorylation.
Each $3$-phosphoglycerate molecule is oxidized, yielding a phosphoenolpyruvate molecule with a high-energy phosphate bond.
The high-energy phosphate is separated from each phosphoenolpyruvate and transferred to ADP, forming ATP and pyruvate, by substrate-level phosphorylation.

The overall Glycolysis reaction is:
$glucose{\text{ }}\left( {6C} \right){\text{ }} + {\text{ }}2{\text{ }}NA{D^ + }\;2{\text{ }}ADP{\text{ }} + 2{\text{ }}inorganic{\text{ }}phosphates{\text{ }}\left( {{P_i}} \right){\text{ }}yields{\text{ }}2{\text{ }}pyruvate{\text{ }}\left( {3C} \right){\text{ }} + {\text{ }}2{\text{ }}NADH{\text{ }} + {\text{ }}2{\text{ }}{H^ + }\; + {\text{ }}2{\text{ }}net{\text{ }}ATP$

Note:
Glycolysis occurs in both aerobic and anaerobic environments and does not require oxygen. During aerobic respiration, however, the two reduced NADH molecules migrate protons and electrons to the electron transport chain, allowing oxidative phosphorylation to produce additional ATPs. Glycolysis also results in the development of a variety of important precursor metabolites.