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Short Answer Questions

Short Answer Questions. Exam 2005.

kylynn-davis
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Short Answer Questions

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  1. Short Answer Questions Exam 2005

  2. What sort of weight change would be observed in an average person if there was 1% mismatch between energy intake and energy expenditure averaged over the course of a whole year? Show your working/logic. (2 marks)List THREE ways of burning fuels without doing work. For each, give a ONE sentence explanation of how the mechanism works. (3 marks) • Part I • Say we consume 10 MJ/day • That’s 3650 MJ/year • 1% of this is 36.5 MJ • Fat tissue is 30 MJ/kg • So the excess (or shortfall) is about 1 kg fat • Part II • Uncoupling through UCP opening in BAT mito • Uncoupling by hydrophobic weak acids • Substrate cycles - examples • Leaky membranes - example • Cytosolic NADH shuttles (!!!)

  3. List FIVE ways (eg, drug or dietary intervention) in which blood cholesterol can be manipulated. In each case give a ONE sentence description of how the intervention works. • Eat less? • but endogenous pool large compared to intake • also abiilty to make cholesterol very high • Inhibitors of HMG-CoA reductase • statins • consequences • Dietary consumption of fatty acids • saturated vs unsaturated • Phytosterols • inhibition of absorption • Resins to prevent reabsorbtion of bile salts • Reference to fluxes/pools

  4. List FIVE ways in which an inhibitor of lipolysis might relieve the symptoms and metabolic problems associated with Type I diabetes • IDDM characterised by hypoinsulinemia which results in uncontrolled lipolysis • Lots of fatty acids • More fatty acid oxidation • Fatty acid oxidation inhibits glucose oxidation (muscle) • Ketone body production • more inhibition of glucose oxidation (brain) • acetone on the breath • Acidosis • Fatty acids, ketone bodies, lactate • More gluconeogenic precursors • lactate, glycerol • more glucose produced • But would it work?? • Fundamental problem is lack of insulin • Would not stop proteolysis • Would not allow fuel synthesis

  5. The table below shows the effect of five different types/periods of exercise on the relative rate of blood glucose oxidation (glucose uptake through to carbon dioxide) and energy usage in leg muscles [Hint: focus on what is limiting the rate of glucose oxidation in each circumstance] The difference between B and A walking – steady state vs initial fatty acid availability. low to start with. then ↑ lipolysis The difference between C and B jogging vs walking ↑ energy expenditure all met by fatty acid oxidation The difference between D and C running vs jogging ↑ energy expenditure not all met by fatty acid oxidation The difference between E and D sprinting vs running white muscles, no time for GLUT-4, endogenous glycogen obvious variation for fatty acid oxidation (or gluconeogenesis, etc)

  6. List FIVE treatment strategies for Type II diabetes. In each case, give a single sentence to describe the basis for the intervention. • insulin • swamp the insulin resistance • negative side effects • anabolic, hypos • sulphonylureas • restores first phase insulin secretion • negative side effets • hypos, weight gain • thiazolidinediones • increased insulin sensitivity • small adipocytes, [metabolically flexible] • exercise • increased insulin sensitivity in muscle • no one insulin sensitive and diabetic • diet • low saturated fat, low glycemic index, low calorie • losing weight • (things from other courses) • biguanides

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