glykolýsu

Glycolysis is a fundamental metabolic pathway that occurs in the cytoplasm of nearly all living organisms. It is the initial process of breaking down glucose, a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound. This process generates a small amount of adenosine triphosphate (ATP), the primary energy currency of the cell, and reduced nicotinamide adenine dinucleotide (NADH), an electron carrier that can be used to produce more ATP later.

The glycolytic pathway consists of ten enzymatic reactions. It can be divided into two main phases: the energy investment phase and the energy payoff phase. In the energy investment phase, ATP is consumed to activate the glucose molecule and prepare it for cleavage. In the energy payoff phase, the cleaved molecules are further processed, yielding ATP and NADH.

Glycolysis does not require oxygen, making it an anaerobic process. Under aerobic conditions, the pyruvate produced by glycolysis enters the mitochondria and is further oxidized through the Krebs cycle and oxidative phosphorylation, yielding a significant amount of ATP. However, in the absence of oxygen, pyruvate can be converted into other products through fermentation, such as lactate or ethanol, allowing glycolysis to continue producing ATP.

This pathway is central to cellular respiration and is conserved across diverse life forms, highlighting its ancient origin and critical role in energy metabolism. It provides the initial step for extracting energy from carbohydrates and supplies intermediates for other biosynthetic pathways.