Just like automobiles require fuel to run, your body need fuel also. The food you eat is your fuel. Most foods are made up of complex molecules, like proteins and carbohydrates. These molecules are broken down into simpler forms through digestion. From here, your cells convert the food into other chemical products to harness the energy stored in these molecules. Glycolsis is one of the chemical reaction chains that yields important products including ATP, pyruvate and NADH.
The glycolysis process is the first step of cellular respiration. Through glycolysis, one molecule of the simple sugar glucose is converted into secondary chemical products. The newly formed molecules are then further modified or used in later reactions depending on the cell's environment. Glycolysis consists of about 10 steps and yields two ATP molecules, two pyruvate molecules and two NADH molecules.
Adenosine tiphosphate, or ATP for short, is a vitally important biochemical. Four molecules of ATP are actually produced by glycolysis, however two are consumed during the reactions. ATP molecules are stored in the cell's cytoplasm and nucleoplasm. They provide the energy the cell needs to perform its functions. The molecule contains three phosphate groups bonded to negatively charged oxygen atoms. The presence of multiple negative charges makes the molecule unstable. When ATP loses one of the phosphate groups, a significant amount of energy is released to form adenosine diphosphate, or ADP.
Glycolysis also yields two pyruvate molecules that are used in aerobic or anaerobic respiration at the end of glycolysis. Aerobic respiration takes place if oxygen is present, while anaerobic respiration occurs with no oxygen. Under aerobic conditions, pyruvate is oxidized to form acetyl coenzyme A. The coenzyme begins a chemical reaction called the Kreb's Cycle. The cycle produces more ATP and NADH. When oxygen isn't present, the pyruvate is reduced to form NADH. A further reaction creates NAD+, which is used in another cycle of glycolysis.
Glycolysis produces two NADH molecules. This enzyme works in the mitochondria. In aerobic conditions, after the Kreb's Cycle an electron transport chain is created. Protons are removed and transported outside of the mitochondria. This creates a strong charge gradient and enough electrochemical potential to create many more ATP molecules. However, in anaerobic conditions the NADH is reused in subsequent rounds of glycolysis.