BIO 105 1st Edition Lecture 7 Aerobic Metabolism Cellular Respiration Lecture Outline I II III IV V Know the characteristics of ATP Be able to identify the difference between Anaerobic and Aerobic Pathways Know the characteristics of glycolysis Be able to identify Lactic Acid Fermentation and Alcohol Fermentation Know the Carbohydrates cycle ATP is Universal Energy Source Photosynthesizers get energy from the sun make ATP in photosynthesis Animals get energy second or third hand from plants or other organisms Regardless the energy is converted to the chemical bond energy of ATP Cells of all organisms make ATP by breaking down carbohydrates fats and protein Main Types of Energy Releasing Pathways Anaerobic Pathways Evolved First Does not require oxygen Start with glycolysis in cytoplasm Completed in cytoplasm Aerobic Pathways Evolved Later Requires oxygen Start with glycolysis in cytoplasm Completed in mitochondria much more ATP 36 glucose Pathways Glycolysis krebs cycle ETS Three Aerobic Pathways Stage 1 Name Glycolysis 2 Krebs Cycle TCA Action enzymes partly break down glucose to pyruvate occurs in cytoplasm uses 2 ATP Generates 4 ATP Net 2 ATP 2 NADH enzymes break down pyruvate to carbon dioxide occurs in Mitochondria generates 2 ATP 6 CO 6 NADH and 2 FADH 3 Electron Transport Phosphorylation ETC ETP also in mitochondria NADH FADH2 give up electrons along with H H gradients drive ATP formation 32 ATP oxygen final electron acceptor forms water Glycolysis Energy requiring steps 2 ATP invested consumed Energy releasing steps Glucose split into two 3 carbon molecules called pyruvate 2 NADH formed 4 ATP formed Net Yield is 2 ATP and 2 NADH Krebs Cycle Citric Acid TCA occurs in Mitochondria 6CO 6 NADH plus 2 more 2 FADH 2 ATP Coenzyme Produced During Glycolysis and Krebs Cycles Total 2 FADH 10 NADH Energy Summary of ATP produced per molecule or glucose Glycolysis 2 ATP formed by substrate level phosphorylation Krebs Cycle TCA 2 ATP formed by substrate level phosphorylation Electron Transport Phosphorylation ETP ETC 32 ATP formed TOTAL 36 ATP Pyruvic acid routed by the organism into one of the three pathways 1 Lactic Acid Fermentation 2 Alcohol Fermentation not in humans 3 Cellular anaerobic respiration only need to know Lactic Acid Fermentation and Alcohol Fermentation Lactic Acid Fermentation Humans ferment lactic acid in muscles when oxygen becomes depleted resulting in localized anaerobic conditions Carbohydrates Primary Food Source metabolized first You eat glucose is absorbed across gut blood transports it throughout the body glucose levels rise in blood pancreas secretes insulin insulin stimulates cells to take up glucose faster cells trap glucose convert it to glucose 6 phosphate first step in glycolysis when glucose amounts are greater than needed ATP goes into high gear ATP level rise some excess glucose stored as glycogen in muscle and liver cells as energy store Between meals when glucose levels drop sends signals to pancreas to convert glycogen in liver and muscle to glucose NOTE Glycogen makes up only about 1 of body s energy reserves about 12 hours worth