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page 74
(a) The lipid in milk is in butter-fat droplets which remain in suspension and give a huge water-fat surface area. Lipase is water soluble and so can only work at the surface of fat in water. Vegetable oil is immiscible with water unless a surfactant is added (bile salts? which are expensive and smelly). Glassware is much easier to wash up after using milk than oil.

(b) glass of thermometer is at room temperature and will have less effect on the higher volume

(c) When a liquid is poured out of a tube, small amounts remain on the glass inside the tube and do not become part of the reaction mixture; As the enzyme volume is smaller, this would be more significant if the enzyme was poured; Pouring the bigger volume gives better mixing.

page 76
1. One enzyme catalyzes the formation of 1"4 bonds; The other enyzme catalyzes the formation of 1"6 bonds;

2. Molecules can be added simultaneously at 1"4 and at 1"6;

3. Heat-treatment denatures enzyme; Curve A shows no enzyme activity/no enzyme mediated conversion;

4. a) increasing rate of conversion earlier/until 35 minutes; rate of conversion levels off; b) every bond formed can either be creating a new glycogen molecule or adding to an existing one; the former leads to an exponential increase in number of glycogen molecules/substrate molecules; until growth in new glycogen molecules slows and available enzyme becomes limiting;

page 80
1.factors affecting activity of catechol oxidase include concentration of enzyme, concentration of substrate (chatechol), pH of solution, temperature, amount of oxygen present(?) 2. negative control= no enzyme solution, replace with 1 ml. of water zero with water only 3. add a given amount of lead ethanoate solution to the test shown, mix gently, filter and read color intensity. Also, include a negative lead control made of ethanoate solvent only, run concurrently. 4. The yellow pigment in the enzyme extract will reflect yellow light, and the differences in concentration of the yellow pigment will not be discernible. Blue wavelengths will be absorbed by the yellow pigment...less pigment will absorb less light- so different pigment concentrations can be measured. 5. Over time, the yellow pigment will react with oxygen to become melanin