The...Yeastiest way to produce energy?
Living organisms catabolize organic molecules within their cells and use the energy released to manufacture ATP by phosphorylating ADP. Many prokaryotes and virtually all Eukaryotes phosphorylate ADP either through fermentation (anaerobic) or respiration (aerobic). Both of these processes involve oxidation of foodstuffs, yet only the latter requires oxygen.
Got that? Didn’t think so. Cellular respiration is a very complex process that consists of many steps that take place inside the cell, in an organelle called a mitochondrion. Mitochondria are responsible for converting digested nutrients into the energy-yielding molecule adenosine triphosphate (ATP) to fuel the cell's activities. This function, known as aerobic respiration, is the reason mitochondria are frequently referred to as the powerhouse of the cell. There are two types of respiration that occur in cells to produce energy. When oxygen is available in the cell, aerobic respiration, as mentioned previously, occurs. When oxygen is not readily available, the process of anaerobic respiration occurs. Aerobic respiration is highly favorable to humans and animals because we require large amounts of energy to function properly. Respiration in the presence of oxygen makes possible the complete oxidation of nutrient compounds into carbon dioxide and water. In fact, ninety percent of the energy yield from the respiratory breakdown of nutrients depends on the existence of aerobic conditions.
When no oxygen is available, respiration can be performed through fermentation and anaerobic respiration. Fermentation is the process by which the electrons and hydrogen ions from the NADH produced by glycolysis are donated to another organic molecule. The reason this is done is to produce NAD+ which in turn is needed to keep glycolysis going, and unless the cell has some so