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 The difference between B and A The difference between C and B The difference between D and C The difference between E and D walking – steady state vs initial jogging vs walking running vs jogging sprinting vs running obvious variation for fatty acid oxidation (or gluconeogenesis, etc) [Hint: focus on what is limiting the rate of glucose oxidation in each circumstance] fatty acid availability. low to start with. then ↑ lipolysis ↑ energy expenditure all met by fatty acid oxidation ↑ energy expenditure not all met by fatty acid oxidation white muscles, no time for GLUT-4, endogenous glycogen

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