IB Biology HL C1.1.9 Measuring Enzyme Reactions Questions

(suggests that) there is no significant difference in percent decolorization;

a. pH , as each enzyme has (optimum) pH at which it functions best

OR

pH out of optimum/OWTTE pH results in denaturation / change in enzyme shape/conformation/ active site;

b. temperature, as increased temperature results in enzyme denaturation / change in enzyme shape/conformation/ active site

OR

low (too low) temperatures cause enzyme inactivity / less enzyme activity/molecule collisions

OR

higher temperatures cause more enzyme activity/molecule collisions;

c. size/shape/surface area/volume/number of the alginate beads as this affects the ratio of exposure of enzyme to the substrate;

d. volume/concentration of the (crystal violet) dye as concentration of substrate affects rate of reaction

OR

volume of the enzyme as the final concentration of substrate/enzyme depends on the volume of the two solutions;

e. type of enzyme/dye as enzymes are substrate specific;

f. time allowed for enzyme reaction as longer or shorter time will impact on the amount/percentage of substrate that will be catalysed / OWTTE;

Naming a variable only is not sufficient for "discuss".

a: Accept too acidic or basic.

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Marking guidance:

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a. suggested method that could be used to measure colour change;

b. measure absorbance/transmittance/OWTTE of light before the experiment/adding laccase/control group

OR

compare colour with colour chart before the experiment/adding laccase;

c. measure absorbance/transmittance/OWTTE of light after the experiment/adding laccase

OR

compare colour with colour chart after the experiment/adding laccase;

d. calculate the (percentage) difference;

a. Colorimeter/spectrophotometer/serial dilutions/colour chart / standard curve.

b and c : A quantifiable reference must be used.

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Marking guidance:

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