Metabolic Pathways Most of the ATP that is generated in the body is produced through the process of oxidative phosphorylation. This process is dependent on a steady flow of oxygen and is thus called an aerobic process. – If an oxygen supply is not readily present organisms can still produce ATP but at a much less efficient rate. Organisms that use both process are called facultative anaerobes (yeast, our muscles). ATP produced through anaerobic fermentation

Alcohol Fermentation glycolysis – 2 ATP – 2 NADH 2 pyruvate oxidized to produce 2 CO 2 & 2 acetylaldehyde – NADH oxidizes the acetylaldehyde 2 NAD + are regenerated Ethanol is the final product – performed by organisms such as yeast

Lactic Acid Fermentation – glycolysis 2 ATP 2 NADH – 2 pyruvate – NADH oxidizes the pyruvate 2 NAD + are regenerated end product is Lactate (ionized form of lactic acid) – performed in our muscles when oxygen is scarce

Other fuels used in the process of energy production starch – hydrolyzed to produce glucose glycogen – like starch but stored in muscles – hydrolyzed to produce glucose proteins – amino group removed via process called deamination to form intermediates of glycolysis – waste products form urea and ammonia fats – glycerol becomes glyceraldehyde-3-phosphate (intermediate of glycolysis) – fatty acid chains are cleaved through beta oxidation to produce Acetyl CoA & are fed directly into the citric acid cycle

Biosynthesis It is important to remember that catabolic processes are coupled to anabolic ones. Much of the food we eat and ATP we produce is used to make important structural and functional components of the body. Regulation of Glycolysis – most control is through feedback inhibition anabolic product made in excess stops the process at a beginning step phosphofructokinase (made in step 3 of glycolysis) serves as an important switch – serves as an allosteric enzyme – has receptor sites for inhibitors and activators » inhibitors – ATP » Citrate – activator » AMP