BIO 105 1st Edition Lecture 7Aerobic Metabolism/ Cellular RespirationLecture Outline: I. Know the characteristics of ATPII. Be able to identify the difference between Anaerobic and Aerobic PathwaysIII. Know the characteristics of glycolysisIV. Be able to identify Lactic Acid Fermentation and Alcohol FermentationV. 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 PathwaysAnaerobic Pathways Aerobic Pathways- Evolved First - Evolved Later- Does not require oxygen - Requires oxygen- Start with glycolysis in cytoplasm - Start with glycolysis in cytoplasm- Completed in cytoplasm - Completed in mitochondria- much more ATP (36/glucose)- Pathways: Glycolysis, krebs cycle, ETS Three Aerobic PathwaysStage Name Action1 Glycolysis -enzymes partly break down glucose to pyruvate-occurs in cytoplasm-uses 2 ATP, Generates 4 ATP- Net 2 ATP, 2 NADH2 Krebs Cycle (TCA) -enzymes break down pyruvate to carbon dioxide-occurs in Mitochondria-generates 2 ATP, 6 CO₂, & 6 NADH and 2 FADH₂3 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 GlycolysisEnergy requiring steps:2 ATP invested/ consumedEnergy releasing steps:Glucose split into two 3-carbon molecules called pyruvate- 2 NADH formed, 4 ATP formedNet Yield- is 2 ATP and 2 NADH Krebs Cycle/ Citric Acid/ TCA- occurs in Mitochondria- 6CO₂- 6 NADH (plus 2 more)- 2 FADH₂- 2 ATP Coenzyme Produced During Glycolysis and Krebs Cycles- Total- 2 FADH₂ + 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 formedTOTAL: 36 ATP Pyruvic acid routed by the organism into one of the three pathways:1. Lactic Acid Fermentation2. 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 takeup glucose faster  cells trap glucose  convert it to glucose- 6- phosphate (first step inglycolysis)  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