TMJC H2 Bio data response questions (Qn)

Tampines Meridian Junior College JC2 H2/9744 Biology Data Response Practice PRACTICE 1 Pyruvate dehydrogenase is a tetrameric enzyme found in the mitochondria that catalyses the conversion of pyruvate to acetyl CoA during cellular respiration. The activity of pyruvate dehydrogenase is inhibited by acetyl Co-A. Fig. 1 shows the relationship between the initial rate of reaction of pyruvate dehydrogenase activity and the concentration of pyruvate at the optimal temperature and pH of the enzyme. All other variables are kept constant. Fig 1

(a) Comment on the trend shown on the graph. [6] ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… (b) On Fig 1, sketch and label a curve to show the effect of adding acetyl Co-A on the initial rate of reaction of pyruvate dehydrogenase activity. [1]

PRACTICE 2 Fig. 2 shows the effect of increasing temperature on the activity of three protein -digesting enzymes: • thermitase from thermophilic Thermoactinomyces vulgaris • subtilisin from Bacillus subtilis • modified subtilisin Fig. 2 (a) Describe, with reference to Fig. 2, the effect of temperature on the rate of protein digestion by thermitase. [3] ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..…

(b) Modified subtilisin is similar to subtilisin, but had eight of its amino acids replaced with different amino acids. Describe and explain the effect of this modification on the activity of subtilisin. [4] ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… ………………………………………………………………………………………………………..… PRACTICE 3 In 1954, an article was published in the British Medical Journal entitled, The mortality of doctors in relation to their smoking habits. One aspect of the investigation studied a very lar