The process you’re referring to is glycolysis, which is the first step in the metabolic pathway of cellular respiration. During glycolysis, one molecule of glucose (a six-carbon sugar) is broken down into two molecules of pyruvic acid (also known as pyruvate), which has three carbon atoms each.
Here’s a brief overview of the process:
-
Investment Phase: Glycolysis begins with the investment of two ATP molecules. This energy investment helps to phosphorylate glucose, making it more reactive.
-
Cleavage Phase: The six-carbon sugar, glucose, is split into two three-carbon molecules called glyceraldehyde-3-phosphate (G3P).
-
Payoff Phase: Each G3P molecule is converted into pyruvate. During this phase, energy is released, and a total of four ATP molecules and two NADH molecules are produced (net gain of two ATP since two were invested).
Overall, glycolysis can be summarized by the following equation:
\[ \text{Glucose} + 2 \text{NAD}^+ + 2 \text{ATP} \rightarrow 2 \text{Pyruvate} + 2 \text{NADH} + 4 \text{ATP} \]
Despite the production of four ATPs, the net gain is two ATPs because two were consumed in the initial stages of glycolysis.
Glycolysis occurs in the cytoplasm of the cell and does not require oxygen, which means it can take place under both aerobic and anaerobic conditions. If oxygen is present, the pyruvate can further enter the mitochondria and undergo aerobic respiration, leading to the production of additional ATP. If oxygen is not present, pyruvate can be converted into lactic acid or ethanol through fermentation processes.