Midterm 1 Review - Dr. Robert Mazzeo PDF

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Dr. Robert Mazzeo...

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MIDTERM 1 REVIEW Saturday, February 15, 2020

11:27

THERMODYNAMICS AND ENERGY 1. Define the First and Second Laws of Thermodynamics. How do these laws relate to bioenergetics of exercise? a. 1st Law: The total energy of the universe is constant. Implies the body must convert energy to do work from other firms; it cannot make new energy b. 2nd Law: Entropy of the universe always increases (implies direction of processes - from more ordered --> less ordered, and vice versa)

2. What are the factors that influence ∆G? a. pH (if more acidic, negatively affects ∆G of ATP. Under standard conditions, when pH is neutral, the free energy for ∆G = -7.2 kcal/mol. If the medium becomes more acidic, it's actually less than that. For example, ∆G is very negative for ATP hydrolysis. In the human body at rest, ∆G = -12. During exercise, depending on certain factors, ∆G could be near 17) b. Temperature (^T --> ^∆G) c. Substrate concentration 3. Fill in the table with the appropriate associations: Reaction Status Uphill/Downhill Endergonic/Exergonic +/- ∆G

Keq >1 or low myosin ATPase, high fatigue resistance, slow oxidative, # mitochondria b. Fast-Oxidative (Type IIA) --> high myosin ATPase, immediate fatigue resistance, high oxidative, # mitochondria c. Fast-Glycolytic (Type IIX) --> high ATPase, low fatigue resistance, fast non-oxidative, # mitochondria 2. What are the key functions and characteristics of regulatory enzymes? a. Generally occur in initial steps of multi-enzyme rx sequence b. Usually irreversible c. Regulated allosterically i. Good strategy to regulate metabolism pathways early 3. What is an isozyme? What is the functional significance of the isozyme pattern for LDH? a. Multiple forms of a given enzyme in an organism. M4 (Type II): high affinity for pyruvate to reduce to lactate. H4 (Heart): high affinity for lactate to oxidize to pyruvate. During training, M-->H favorable for carbohydrate sparing purposes 4. What are the metabolic pathways involved in the production of energy from CHO's during muscular contraction? How are these pathways regulated? a. Glycogen --> CO2 pathway; carbs in liver, blood, and muscle 5. What is the difference between "non-oxidative (anaerobic)" and "oxidative (aerobic)" glycolysis? a. Anaerobic: 2 lactate, 2 ATP, 0 NADH b. Aerobic: 2 pyruvate, 2 ATP, 2 NADH 6. What is the primary physiological role of liver and muscle glycogen during an acute bout of exercise? How do these change with varying degrees of exercise intensity, duration, and training status? a. Liver & muscle glycogen limiting factor. Over time, liver & muscle carbs deplete (muscle first), so plasma FFA and triglycerides used 7. How is glycogen loading accomplished and how does it affect endurance performance? a. Deplete glycogen stores ahead of time (e.g. through diet or exercise) before exercise for 3-5 days & then drink carbs to super-compensate. The stimulus is the depletion of glycogen stores in the muscle, and, to some extent, the liver. They remain depleted for a while because a diet wouldn't see as much intake and because exercise would cause natural depletion. So, when the switch to high-carbs begin, the body, because of the effect of low glycogen stores on insulin sensitivity and glycogen synthase causes a supercompensation with more glycogen in the muscle and liver than before the dietary manipulation. 8. What is the mechanism whereby CHO drinks during exercise lead to an improvement in performance? a. Muscle glycogen depletions IS NOT slowed, so muscle glycogen is depleted at the same rate, whether an athlete drank a sweetened placebo or CHO drink. Instead, it helps to maintain a blood source of glucose for carbohydrate oxidation. Big spike in gluc & insulin, promoting gluc uptake in insulin-dependent cells, even if glycogen depleted 9. An endurance athlete wants to know about a pre-race meal and carbohydrate supplementation during their event. What would you advise?

a. Consuming carbs 5-10 minutes before workout from 375-750 mL/hr of 8% CHO sol'n. After exercise, 1.0-1.5 g/kg within 30 minutes @ 2-hour intervals for 6 hours Citric Acid Cycle & Electron Transport Chain 1. How is NADH transferred from the cytoplasm into the mitochondria? What purpose does this serve? a. Electrons are transferred via either 2. What mitochondrial-related adaptations occur with endurance training? a. ^Mitochondria = ^size and ^number = ^FAT & CHO utilization = more efficient carb sparing 3. Where are ATP, NADH, FADH2, and GTP used and/or produced during the complete oxidation of glucose to 6CO2? For 1 glucose molecule, what is the net ATP yield from glycolysis and oxidation? a. Look at roadmap and lecture notes 4. How does the ETC work? What purpose does it serve? a. Look at lecture notes

5. Endurance training increases an individual's ability to spare carbohydrates and prolongs time to fatigue. Discuss the biochemical adaptations in carbohydrate metabolism & oxidative capacity that occur with endurance training, and how these changes lead to improved performance? a. ETC, CAC, liver sparing, how LDH ∆'s to favor pyruvate oxidation, glycolysis is slowed with endurance training LACTATE METABOLISM 1. What are the effects of acute submaximal exercise on blood lactate levels? What are the causes of the lactate threshold during a GXT? How does the lactate response to exercise change with endurance training, and why? a. Lactate levels increase slightly. Recruitment of Type II, accelerated glycolysis, and mismatch btw/ Ra and Rd cause threshold. Endurance causes decrease in Ra & increase in Rd, which, in turn, shifts threshold higher relative to workload 2. Describe in detail the bicarbonate buffering system. What physiological function does this reaction serve? a. When lactic acid builds up due to anaerobic metabolism, it dissociates into lactate to keep blood pH from lowering. The H+ reacts w/ bicarbonate to yield carbonic acid, which then gets converted by carbonic anhydrase into H2O and CO2. The increased production of CO2 leads to an increase in the buffering of blood lactic acid 3. What are the factors contributing to the "oxygen debt?" a. Re-synthesis of creatine phosphate in muscle, lactate conversion to glucose, restoration of muscle and blood O2 stores, elevated body temperature, post-exercise elevation of HR & breathing, elevated hormones. MISCELLANEOUS Creatine Monohydrate: has to get phosphorylated. Creatine Monohydrate has to get phosphorylated in the muscle before it can do anything good. So, you take the CM, it gets into the blood, the muscles take it up and, when it's in the muscle, it gets phosphorylated....