0.25 Bis2a 07.1 glycolysis  (Page 34/12)

Intoduction to glycolysis

You are about to begin a series of modules that focus on the oxidation of carbon compounds. This process serves two distinct purposes for any cell. The first is the generation of metabolic substrates , small carbon based molecules that all cells need in order to "build" or synthesize larger complexes such as monomers which lead to the formation of macromolecules or polymers, such as proteins, or polysaccharides. All cells need twelve (12) basic building blocks or metabolic substrates. In the next few modules we will learn where these metabolic substrates come from and how cells synthesize them. The second purpose is the generation of cellular energy. This can be in the form of ATP (or ATP equivalents) or the formation of reducing power . This is primarily in the form of NADH , NADPH or FADH ₂ .

A note from the instructor as to what is expected of you to know from the reading and lecture

Glycolysis: an overview

So what is glycolysis: it is the process of oxidizing 1 molecule of glucose to 2 pyruvate molecules and the generation of 2 NADH molecules and 2 ATP molecules. Cells can generate cellular energy from the process, 2 ATP molecules are obtained for every molecule of glucose entering the pathway as well as 2 molecules of NADH are generated. In many organism, the oxidation of glucose ends with the generation of pyruvate. For these organisms, for every 1 molecule of glucose oxidized, cells generate only 2 ATP molecules. In other words, these organisms only utilize or extract a small amount of the total potential energy within the glucose molecule. However, for many other organisms, including us humans, the end product pyruvate can be further oxidized by a series of additional reactions, which will be discussed later. In general, these organisms first oxidize pyruvate to acetate or acetyl~CoA, and then the acetyl~CoA is completely oxidized to CO ₂ by the Tricarboxylic acid cycle or TCA cycle .