Short Answer Questions Exam 2004

64. Measuring Energy Expenditure What ways are principles and advantages/disadvantages of TWO different methods of measuring whole body energy expenditure? (5 marks)

65. Lipogenesis – Big Picture The overall, balanced equation for the synthesis of palmitate (a 16-carbon fatty acid) from glucose is: 9 glucose + 8 O 2 → 2 palmitate + 22 CO H 2 0 –Why is there no mention of ATP or NADPH in this equation? –Palmitate is a highly reduced hydrocarbon chain – so why is mentioned in this equation? –At what steps were the carbon dioxide molecules released? –Roughly, what percentage of the energy in glucose is lost in doing this conversion (Mw palmitate = 256, Mw glucose = 180) –How does lipogenesis affect the respiratory quotient?

66. Fuel oxidation in liver To sustain a high rate of fatty acid oxidation in muscles it is necessary to have a large demand for ATP synthesis and a rapidly working Krebs Cycle. However, this is not the case in liver. Why? (5 marks)

67. Exercise The following strategies are often employed by athletes. Explain why. Justify your answers on biochemical terms but use NO MORE than one or two sentences for each strategy. (5 marks) –Dietary creatine supplementation –Dietary carnitine supplementation –Consumption of sodium bicarbonate before a race –Dietary Coenzyme Q supplementation –Consumption of caffeine before a race

68. NIDDM The insulin sensitivity and fasting blood glucose concentration of about 40 subjects was measured. The graph opposite shows the result. Each circle is a separate individual. (5 marks) –What is the name and principle of the technique which would have been used to measure the insulin sensitivity of each individual? –On a separate graph, draw the results that you would expect to see if an oral glucose tolerance test was given to individuals in each of the ‘groups’ A, B & C –What do THESE results tell us about the relationship between hyperglycemia and insulin resistance?

Insulin Sensitivity fasting blood [glucose] (mM) high low A B C