Question

In cells, glucose, a six-carbon molecule, is converted into two three-carbon molecules by a reaction that releases energy. How would you classify this reaction?

Answer 1

Glycolysis is the reaction in which glucose is converted into two three-carbon molecules, pyruvate. This process takes place in the cytoplasm of cells and does not require oxygen. It is the first step in cellular respiration and produces energy in the form of ATP and NADH.

Step-by-step explanation:

The reaction in which glucose, a six-carbon molecule, is converted into two three-carbon molecules is called glycolysis. Glycolysis is the first step in cellular respiration, a process that releases energy from glucose to produce ATP, the energy currency of the cell. In glycolysis, glucose is broken down into two molecules of pyruvate through a series of enzyme-catalyzed reactions. This process takes place in the cytoplasm of the cell and does not require oxygen, making it an anaerobic process.

Glycolysis can be summarized in the following steps:

1. Glucose is phosphorylated by the enzyme hexokinase, using one molecule of ATP. This converts glucose into glucose-6-phosphate.
2. Glucose-6-phosphate is converted into fructose-6-phosphate by the enzyme phosphoglucose isomerase.
3. Fructose-6-phosphate is phosphorylated by the enzyme phosphofructokinase-1, using one molecule of ATP. This converts fructose-6-phosphate into fructose-1,6-bisphosphate.
4. Fructose-1,6-bisphosphate is split into two three-carbon molecules, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.
5. Glyceraldehyde-3-phosphate is oxidized and phosphorylated, producing two molecules of NADH and two molecules of 1,3-bisphosphoglycerate.
6. 1,3-bisphosphoglycerate is converted into 3-phosphoglycerate by the enzyme phosphoglycerate kinase. This reaction also produces two molecules of ATP.
7. 3-phosphoglycerate is converted into 2-phosphoglycerate by the enzyme phosphoglycerate mutase.
8. 2-phosphoglycerate is converted into phosphoenolpyruvate by the enzyme enolase.
9. Phosphoenolpyruvate is converted into pyruvate by the enzyme pyruvate kinase. This reaction produces two molecules of ATP.

Overall, the conversion of glucose into pyruvate results in the release of energy in the form of ATP and the production of NADH, which can then be used in the later stages of cellular respiration to generate more ATP.