Study Questions KIN 150 PDF

Study questions lecture 1 and 2, Phosphagen and glycolysis 1. T/F Our ATP levels are constant, and relatively low, at any given time. What changes is how quickly we replenish it depending on our energy needs (i.e. rest vs exercise). True because during exercise ATP is regenerated...

Study questions lecture 1 and 2, Phosphagen and glycolysis 1. T/F Our ATP levels are constant, and relatively low, at any given time. What changes is how quickly we replenish it depending on our energy needs (i.e. rest vs exercise). True because during exercise ATP is regenerated faster through glycolysis, oxidative phosphorylation and phosphocreatine. At rest, it is replenished slower. 2. T/F We can deplete our ATP stores during exercise, but not our PCr stores. False, we deplete both, ATP used for energy while PCr is used to help regenerate ATP 3. In a lean individual, what is the order, from smallest to largest, of the bodily fuel stores that they could rely on for survival, in times of famine? Glycogen storage (smallest) , protein storage, fat storage (largest) 4. Name the three main pathways for ATP resynthesis, explain how they differ in terms of their maximal rates of ATP turnover and what kind of activities rely more on each one. Glycolysis , phosphagen system, oxidative phosphorylation 5. Describe the phosphagen system, the creatine kinase reaction, the myokinase reaction (and where in the cell they occur) and the role of mitochondria in helping replenish depleted PCr stores. 6. Does creatine supplementation work? If so, how? And what types of performances would it benefit most? 7. Describe glycolysis – where it occurs, what goes in, what comes out, how much ATP is invested and is obtained. Breakdown of glucose no oxygen required, replenished ATP at high rate for up to 3 mins, 2ATP invested and net ATP gains is 2, to form 2 pyruvate molecules and 2 NADH 8. What are the major and minor sources of glucose for glycolysis? Muscle glycogen is a major source and blood glucose maintained by liver glycogen and food intake GLUT-4 stimulated by insulin and muscle contraction/calcium 9. What is the name of the enzyme responsible for breaking down glycogen into individual units of glucose? Glycogen phosphorylase = break down glycogen into individual units of glucose  10. Name 3 things that determine how quickly muscle will take up glucose from the blood. Insulin, exercise intensity and duration, Glut-4 11. How does it differ from oxidative phosphorylation? 12. Name the 3 enzymes, the intracellular, and the hormonal factors that regulate the rate of glycolysis. What kind of conditions will stimulate glycolysis or slow it down? 13. Which of the 3 enzymes is rate-limiting? What does rate-limiting mean in the context of glucose breakdown? PFK is rate limiting meaning it helps control the speed and rate of entire pathway. It dictates how fast glucose is broken down for glycolysis. 14. How much of the total ATP available from a glucose molecule is obtained via glycolysis alone (i.e. glucose to pyruvate?). What needs to happen to the pyruvate to harvest the remainder of the energy? 2 ATP is obtained alone The two fates of pyruvate happen to harvest the remainder of the energy, pyruvate oxidation, lactate formation and oxidation 15. What are the 2 fates of pyruvate? Lactate formation and oxidative metabolism 16. Why is lactate formation useful for maintaining a fast rate of glycolysis? 17. In what situations does lactate formation increase sharply? Where does it go, if it cannot be taken up fast enough by mitochondria? 19. Define oxidation and reduction. What is the main role of NADH and FADH2 in metabolism? Oxidation = loss of electrons Reduction = gain of electrons NADH and FADH2 help transport Hydrogen into the inner membrane of mitochondria 20. What is the citric acid cycle, what is its main purpose? Where in the cell does this cycle occur? 21. Describe what happens in the electron transport chain, and how ATP is regenerated. What is the role of oxygen? 22. Why can we regenerate ATP so much more quickly using the phosphagen system, followed by glycolysis, followed by mitochondrial respiration? (Hint – think about how long it takes you just to describe each process!) Carbohydrate metabolism questions 1. Describe the different types of carbohydrates (monosaccharides, disaccharides, polysaccharides, and dietary fiber) Monosaccharides = 1 sugar Disaccharides = 2 sugar, maltose (starch) , lactose (dairy), sucrose (table sugar) Polysaccharides= multiple sugar, Plant vs Animal 2. Describe how carbohydrates are digested and absorbed. Enzymes digest larger saccharides into monosaccharides before they can be absorbed in intestine DiSacch and PolySacch are absorbed slowly MonoSacch – absorbed the fastest 3. Describe the primary role of muscle vs liver glycogen Muscle glycogen – immediate energy source for muscle contraction Liver glycogen – regulates blood glucose levels and provide glucose in blood stream especially during fasting or low energy conditions, critical in gluconeogenesis 4. Describe and compare 2 practices for carbohydrate loading in the days preceding an endurance competition. What are some disadvantages to the “classical” method of carbo- loading? 5. What is the glycemic index? Why do we care about the GI index of different foods? IT represents the effect of CHO source on a person’s blood glucose level High and Moderate Glycemic = easier to digest before exercise We care because it helps manage our blood sugar, and energy levels 6. Describe the metabolic and performance effects of carbohydrate ingestion 1-4 hours before exercise. What types of CHO are recommended, and what should be avoided in these meals/snacks? It maximizes glycogen storage and provides glucose for intestinal absorption. CHO ingestion 1-4 hrs before exercise allows for maximum storage and increased intestinal absorption 7. Describe the metabolic and performance effects of carbohydrate ingestion during exercise Depends on duration and intensity of exercise, for long, strenuous events it is best to balance maximizing CHO oxidation while minimizing GI discomfort Can mix glucose and fructose to increase CHO oxidation rate during exercise CHO intake during exercise can lead to a positive effect on motor skills, faster recovery, improved performance, increase endurance, improve overall CHO oxidation 9. During exercise: describe the effect of different CHO feeding strategies on CHO oxidation and performance: 1. Effect of timing, quantity, and CHO composition (i.e. 1 vs 2 or more types of CHO) Liquid Form CHO Fast absorption and gastric emptying Sloshing around in stomach is a con Combined CHO+ water intake Solid Form CHO More energy dense Slower digestion Must take water separately 10. Explain why oxidation rates are higher when ingesting more than 1 type of monosaccharides. What combination, and in what amounts, results in the greatest carbohydrate oxidation rate? Oxidation rates are higher due to the absorption of mechanisms and metabolic pathways. The 2:1 ratio of glucose to fructose is optimal for maximizing CHO oxidation during exercise 11. What (if any) form of CHO supplementation is best during exercise? Solid, liquid, semi-solid (i.e gels)? Liquid Form CHO Fast absorption and gastric emptying Sloshing around in stomach is a con Combined CHO+ water intake Solid Form CHO More energy dense Slower digestion  Must take water separately 12. Describe the two phases of glycogen resynthesis after exercise. 1. What factors affect the rate of glycogen synthesis? Why is it important to consume CHO soon after finishing an exercise bout (i.e. within 2hrs)? First Phase: Rapid phase of glycogen synthesis (lasts 30-120 min after exercise ends) Insulin independent GLUT-4 is high Glycogen synthase very high because glycogen depleted from exercise Second Phase: Slow Phase (2 to 24 hrs post exercise) Insulin Dependent Insulin remains high Larger GLUT-4 response due to high insulin 13. Give generally accepted guidelines for carbohydrate intake: ▫ before (days, and hours) prolonged strenuous exercise, and ▫ during prolonged strenuous exercise (>1hr, >2hr) ▫ After prolonged exercise, when another event is to be performed later that same day or the next day 14. Give generally accepted guidelines for daily carbohydrate intake for athletes during moderate or heavy training 5-10 g/kg for someone moderate to heavy training Fat Metabolism Fat Metabolism - Study Questions 1. Describe the chemical properties of various lipids (fats), including the differences between saturated and unsaturated fatty acids, and the functions of dietary lipids 2. Where is fat stored in the body? Name the different sources and their relative abundance. Adipose Tissue (greatest storage) Intramuscular Triacylglycerol (TGs) Plasma TGs Plasma fatty acids (least storage) 3. Give a general overview of the 7 steps of fat metabolism ` 1. Lipolysis 2. removal of FA from adipose cell 3. FA transport into blood stream via albumin 4. FA enter muscle cell 5. FA transported to mitochondria 6. B-oxidation 7. TCA cycle, electron transport chain 4. What is lipolysis, name the main enzyme responsible for it and the physiological states that activate it. Breakdown of triglycerides into free fatty acid and glycerol, HSL (hormone sensitive lipase) main enzyme responsible Activated by stress, fight or flight, starvation, low insulin levels 5. What hormones activate or inhibit lipolysis? SNS (Epi and Norepi) activate HSL and lipolysis Insulin Inhibits 7. What is the major factor influencing the removal of FA’s from the fat cell? Why is it compromised during very strenuous exercise?  Adequate blood flow to fat tissue is the major factor. It becomes compromised during strenuous exercise because the blood vessels begin to vasoconstrict reducing the blood flow to fat tissue 8. How are most fatty acids transported in the blood, from the adipocyte to the muscle? Transported via albumin 9. Why does FFA appearance in the blood increase from rest to moderate exercise? Increases due to enhanced lipolysis, greater blood flow to adipose tissue and the shift of using fat as a fuel source 10. Name 2 cell membrane proteins that play a role in taking up fatty acids from the blood into the muscle cell. 12. What is the role of carnitine in fatty acid transport into the mitochondrial matrix? Carnitine helps transfer FA into mitochondrial matrix FA is transported into mitochondria by CPT1 a rate-limiting step 13. Which enzyme is considered the rate-limiting enzyme in fatty acid oxidation? Carnitine Palmitoyl Transferase (CPT1) 14. What is beta oxidation? What does it produce? Beta oxidation is the sequential removal of 2-carbon units from the FA chain, in the form of acetyl COA Breaks FA into acetyl COA Produces NADH and FADH2 that contributes to ATP production 6. What type of muscle fibers store the most intramuscular triglycerides (IMTG)? Even though they are less abundant than TGs in fat cells, what is the main advantage of IMTG during exercise? Type 1 muscle fibers store the most IMTG, Main ADV. Is that IMTG doesn’t need to be transported in the blood to be used by muscle 17. What 2 factors can help increase IMTG storage capacity? Aerobic training  High fat diet 18. Describe the effect of exercise duration on fatty use (if no food is consumed during exercise). If no food is consumed during exercise, after more than 1 hour of exercise fat becomes the main fuel source, from 30 min to 1 hour, reliance on fat increases as glycogen depletes, first 30 mins of exercise you begin to use glycogen and CHO storage. 19. Describe the effect of exercise intensity on fat use. Lower to moderate intensity: fat is the main energy source Higher intensity: the balance of fuel shifts and CHO is being used due to increased energy demands 20. Describe the crossover concept, and how successful endurance training affects crossover point. The crossover is when the athlete obtains 50% of energy from CHO oxidation and 50% from fat oxidation. Successful endurance training affects crossover point by shifting to the right, the body becomes more efficient at oxidizing fat meaning it delays the point where the energy is shifted form fat to CHO 21. Describe how training improves our ability to oxidize fat at the cardiovascular, mitochondrial, and cellular transport levels. Mitochondrial: increase in mitochondrial enzymes = increase oxygen utilization and oxidative energy Increase in TG storage = more oxygen ready for muscle Improved uptake of FA from bloodstream Increase O2 delivery in blood = more oxygen to muscles Increase CO = increase VO2max 22. Describe what happens when we switch to a low carb, high fat diet : how do we adapt to having very little glucose around? What does our brain use instead of glucose? When we switch, the liver produces ketone bodies from FA breakdown, brain and other tissues adapt to use ketone and the ability to oxidize fat in the muscles and other tissues increase dramatically. 23. Where are ketone bodies formed, from what macronutrient? Occurs in the liver and converts FA into acetyl COA 24. Why are protein needs increased when following a high fat, low carbohydrate diet? Glycogen storage low = increase protein breakdown for energy 25. Name a medical condition that seems to be relieved by switching to the LCHF diet. Epilepsy, LCHF can help prevent seizures as it improves neuronal energy metabolism 26. In athletes, what are some of the proven effects (to date) of the LCHF diet on exercise metabolism and endurance? LCHF is much better at oxidizing fat which means glycogen storage is spared 27. Name practical and physiological limitations that may be disadvantages to adopting a LCHF diet in athletes who train to compete in endurance events at a high level (i.e able to maintain very high % of their VO2max during a prolonged event like a marathon) Reduced glycogen stores = limited athlete ability for HIIT efforts Impairs max rate of glycogenolysis Slow energy production from fat = fatigue Must adjust protein intake due to increase in protein breakdown