glicolízissel

Glicólisis is a fundamental metabolic pathway that occurs in the cytoplasm of nearly all living organisms, both prokaryotic and eukaryotic. It is the initial process of cellular respiration, breaking down glucose, a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound. This breakdown yields a net gain of two adenosine triphosphate (ATP) molecules and two molecules of reduced nicotinamide adenine dinucleotide (NADH).

The process of glycolysis is divided into two main phases: the energy investment phase and the energy payoff phase. In the energy investment phase, two ATP molecules are consumed to destabilize the glucose molecule and prepare it for cleavage. Following this, in the energy payoff phase, the molecule is split into two three-carbon units, and through a series of enzymatic reactions, ATP and NADH are generated.

Glycolysis does not require oxygen and can therefore occur under both aerobic and anaerobic conditions. In the presence of oxygen, pyruvate proceeds to the citric acid cycle and oxidative phosphorylation for further ATP production. Under anaerobic conditions, pyruvate is converted into other end products, such as lactate or ethanol, a process known as fermentation, which regenerates NAD+ needed to sustain glycolysis. This ancient pathway is crucial for providing energy for cellular functions and serves as a central hub for carbohydrate metabolism.