4255370
| Pregunta | Respuesta |
| Define high intensity (intermittent) exercise (HIE) | A continuous period of activity lasting between 10 seconds and 4 minutes. |
| Name three ways to investigate HIE | 1) Non-motorised treadmill 2) 1 legged knee extension 3) Wingate test |
| Compare the peak power output from HIE and Vo2 max. | During HIE peak power output that is reached is a lot higher than Vo2max. |
| What is the term for the peak power output that is over the Vo2max level? | Supramaximal exercise |
| What are the main energy systems used during HIE? (3) | 1) ATP/ADP system 2) PCr system 3) Glycolysis |
| Describe the ATP/ADP system. | ATP reacts with ATPase, this releases a phosphate group (energy) leaving ADP. PCr, glycogen, myokinase then resynthesise ATP. |
| Describe the PCr system | PCR is turned into creatine. Creatine kinase catalyses this reaction. This reaction generates a free phosphate group. Oxygen is required |
| What is the resting PCr concentration in muscle? How long can it regenerate ATP for? | 75-90 mmol/kg dm ~ 10 s of maximal exercise |
| How is PCr resynthesised? | |
| If there is not enough oxygen what happens? | Oxygen becomes a limiting factor. |
| What is the glycogen resting concentration in muscle? What does this depend on? | 300-700 mmol/kg dm Depending on diet and training status |
| How does glycogenolysis work? | Glycogen is converted to glucose-1-phosphate (enzyme: glycogen phosphorylase) Glucose-1-phosphate is converted to glucose-6-phosphate (enzyme: phosphoglucomutase) |
| How does glycolysis work? | Glucose-6-phosphate is converted to 2x pyruvate (enzyme: phosphofructokinase) 2 pyruvate are either turned into lactacte (enzyme: lactate dehydrogenase LDH) or into Acetyl CoA (enzyme: pyruvate dehydrogenase PDH) |
| What is more likely to be used as a key source of energy? | Glycogen |
| Why is glucose unlikely to be a key source of energy? | It only generates 2 ATP, glycogen creates 3. This is because turning glucose into glucose-6-phosphate costs an ATP. |
| What is glycogen+3ADP+3Pi converted to, using which enzymes? | -> 3ATP + 2 lactate + 3H+ Enzymes: LDH, PFK, Phosphorylase |
| HIE increases ATP cytosol = an increase in ADP, what does this lead to? | Myokinase (adenylate kinase) reaction |
| state the adenylate kinase reaction | ADP + ADP -> ATP + AMP Enzyme: Adenylate kinase |
| If AMP increases by too much in the muscle what does this mean? | It is toxic |
| How is AMP removed from the bloodstream? | It is transformed into ammonia. |
| How long does muscle ATP contribute towards energy production during exercise? | 2/3 seconds |
| How long does muscle ATP + ATP-PCr contribute towards energy production during exercise? | up to 10 seconds |
| How long does muscle ATP + ATP_PCr + Aerobic glycolysis contribute towards energy production during exercise? | 90 seconds |
| How long does muscle ATP + ATP_PCr + Aerobic glycolysis + 02 system contribute towards energy production during exercise? | As long as the exercise lasts. |
| What happens to levels pre and post exercise for: ATP PCr Glycogen Glucose | ATP stays constant pre and post exercise PCr decreases Glycogen Decreases Glucose increases due to an increase of GLUT-4 |
| What fibre type has a higher PCr concentration? | Type 2 has a higher concentration than type 1. |
| What fibre type has a higher PCr degradation? What does this show? | Type 2 Type 2 fibres are recruited more during HIE |
| Between 0-6 seconds what contributes most to the ATP turnover rate? | PCr hydrolysis |
| Between 6-15 seconds what contributes most to the ATP turnover rate? | Glycolysis |
| Between 15-30 seconds what contributes most to the ATP turnover rate? | Oxidative phosphorylation is most prominant |
| Can hormones regulate energy production during high intensity exercise? Why? | No They are too slow |
| How is energy production regulated during HIE? Name the 5 things that regulate energy production | Allosteric regulation ADP Pi AMP IMP Ca2+ |
| What happens to muscle pH during HIE? Why? | Muscle pH decreases due to lactic acid. |
| What happens to ADP and AMP during HIE? | ADP & AMP increase rapidly then plateau |
| Explain the process of converting glycogen to acetyl-CoA. | Glycogen -> glucose-1-phosphate -> fructose-6-phosphate -> fructose 1, 6-diphosphate -> 2xpyruvate -> acetyl CoA. |
| Which enzymes affect this chain of events and at what points? | Glycogen phosphorylase alpha converts glycogen to glucose-1-phosphate PFK converts fructose-6-phosphate to fructose-1, 6-diphosphate Pyruvate Dehydrogenase (PDH) converts 2xpyruvate to acetyl-CoA. |
| What are the factors that allosterically regulate glycogen phosphorylate activation during HIE. | Ca2+ Mg2+ ADP AMP IMP Pi |
| What enzyme deactivates glycogen phosphorylase? | Phosphorylase phosphatase |
| What enzyme activates glycogen phosphorylase? | Phosphorylase Kinase |
| How do we explain glycogen phosphorylase for 3 0seconds of exercise? | |
| How do we allosterically regulate pyruvate dehydrogenase activiation during HIE? How do we activate PDH? | PDH phosphatase |
| How do we allosterically regulate pyruvate dehydrogenase activiation during HIE? How do we deactivate PDH? | If there are high levels of ATP, citrate, Pi, Acetyl CoA, CoASH ratio. |
| What happens to PDH during 30s of exercise? | First 15 s it rises 15-30 s PDH activity plateaus. |
| When repeated bouts of HIE were completed how many participants could resynthesise PCr? How long did it take? | A quarter of participants It took 8 minutes. |
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