PET 3380c—REVIEW SHEET EXAM 1 FALL 2011 Chapter 5, 6, 7, and 8 (from both lectures and text) Bioenergetics 1. What is ATP? How does it function? How is ATP formed? a. ATP – Adenosine Triphosphate – Potential energy within nucleotide molecule, and powers all of the cell’s energy –requiring processes. i. Extracts and stores potential energy in the form of ATP ii. Transfers chemical energy in ATP to perform biologic work b. Formed: PCr, Glycolysis, Cellular Oxidation by Electron Transport Chain, Oxidative Phosphorylation and Krebs Cycle 2. Differentiate between aerobic and anaerobic metabolism. a. Aerobic – energy-generating catabolic reaction in which oxygen serves as the final electron acceptor in the respiratory chain and combines with hydrogen to form water. More energy is produced but at a slower rate. i. Glucose -> pyruvate -> Acetyl CoA ii. Net ATP = 14 ATP b. Anaerobic – energy-generating catabolic reaction that does not utilize oxygen. (PCr). Produces a large amount of energy quickly, but is quick to fatigue (~15sec) i. Glucose->pyruvate -> lactate ii. Net ATP = 2 ATP3. Describe glycolysis. Glycolysis – glucose degradation to form ATP. Occurs in Cytoplasm of cell. Crucial for exercise lasting up to 90seconds.a. Know net ATP yield, depending on substrate used (glycogen or glucose), and know what other energetic molecules are formed (e.g. NADH + H+) Glycogen = 1 Less ATP than Glucose. Anaerobic = 2/3 ATP, Aerobic = 14/15 ATP (2/3 ATP + 4 NADH) NADH = 3 ATP b. How is lactate formed during glycolysis? What are the conditions under which it is formed? -Lactate formation: when oxygen is low and the ETC cannot process all NADH hydrogen Ions, and these unprocessed hydrogen ions combine with pyruvate to form lactate via lactate dehydrogenase. -Lactate formed when energy demands exceed oxygen supply/rate of use. Usually during intense exercise 4. Describe the Krebs Cycle (Citric Acid Cycle). Utilizes Pyruvate (product of Glycolysis) to generate more ATP. Converts Pyruvate into Acetyl CoA and degrades into CO2 and H+ (goes into Electron Transport Chain to produce energy) a. Know what happens to pyruvate before entering the Krebs cycle. -Pyruvate converts into Acetyl CoA via Pyruvate dehydrogenase and produces NADH + H+. This is an irreversible step b. Know what important high energy molecules are formed (e.g. FADH+, NADH + H+, ATP) -NADH = 6 = 24 ATP -FADH = 2 = 4 ATP -ATP = 0 = 0 ATP -GTP = 2 = 2 ATP -Total = 30 ATP in Krebs Cycle (2 pyruvate forms for every glucose, so it cycles twice) 5. Describe the ETC. -Production of ATP in the mitochondria. Utilizes Oxidative Phosphorylation to transfer electrons from NADH and FADH2 to oxygen and produce ATP. Governed by proton gradient of stored energy and inner mitochondrial membrane potential a. Know what the role of NADH + H+ and FADH+ in the ETS and the differences in energy yield. -NADH + H+ = coenzyme that gains H+ and 2 e-; NAD can produce 3 ATP -FADH = coenzyme that gains 2 H+ and 2 e-; FADH can produce 2 ATP b. Know the general mechanism by which energy is produced in the ETS. -An electron transport chain (ETC) couples electron transfer between an electron donor (such as NADH) and an electron acceptor (such as O2) with the transfer of H+ ions (protons) across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of adenosine triphosphate (ATP). 6. Be able to give a general description of beta oxidation. -Splitting 2-Caron acyl fragments from a fatty acid. Production of energy with NAD+ and FAD, H+ goes into the electron transport chain (ETS) and beta oxidation continues degradation to form acetyl-CoA for the Krebs Cycle/Citric Acid Cycle.7. What is the primary fuel for rest, light to moderate exercise, and heavy exercise? Rest – Aerobic Metabolic Pathways – Typically from Fat Oxidation Light to Moderate Exercise – Aerobic Metabolic Pathways (Glycolysis, Krebs Cycle, B-Oxidation, Electron transport Chain) – Buffers Lactic Acid and prevents fatigue Heavy Exercise – Anaerobic Metabolic Pathways (PCr & Glycolysis) – Produces large amount of energy for a short time period, easy to fatigue 8. Describe active and passive recovery. What effect do they have on lactate removal? Active Recovery – submaximal exercise, that is believed to prevent muscle cramps and stiffness and promote overall recovery Passive Recovery – total inactivity, Lying down, massage, cold showers -Performing Aerobic Exercise (Active Recovery) accelerates blood lactate removal 9. What is the fate of lactic acid? 1. Energy production via the Citric Acid Cycle (70%) 2. Re-formation of glycogen (20%) 3. Reloading of the blood cells, myoglobin and lungs with oxygen (10%) VO2max 1. Explain the concept of VO2 max, include what it measures, how you determine if a subject has reached it, and explain clearly how this information can be used. VO2 Max –greatest amount of oxygen a person can consume, transport and utilize to produce ATP Measures: Max Oxygen uptake or Max Aerobic Capacity VO2 Max reached: Leveling –off or peaking-over in oxygen uptake during increasing exercise intensity; Blood lactate reach at least 8 to 10; attainment of near age-predicted max HR 2. Explain some of the factors responsible for the improvement in VO2 max through exercise. Include the cardiovascular changes one might expect to see with exercise. -Intensity and Duration will increase VO2 Max. Doing anaerobic training will greatly increase VO2max compared to aerobic training. Specificity of training and Physiological adaptations (more mitochondria, aerobic enzyme, myoglobin, etc) increase VO2max. 3. How does the concept of specificity apply when talking about VO2 max? a. Here include; mode of exercise, subject fitness status, and different types of equipment one might use to measure VO2 max. For example know if and why differences might occur between cycling VO2 max and running. -Mode of Exercise – VO2 max test by Running, Cycling, Hand Crank or Swimmers: Running best test VO2 max plateau, while the others best test VO2 Max Peak -Subject fitness status – A trained athlete scores a better VO2 max than a sedentary person 4. What are some of the factors that account for the differences in VO2 max between women and men?-Body Composition – Women have more fat -concentration of Hemoglobin -Social Factors that prevent women from being active? 5.
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