HWrkSht 1_15
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1. All proteins are composed of
a. Genes
b. DNA
c. Amino acids
d. Bases
2. Enzymes act as catalysts because they
a. Are composed of protein
b. Act on all substrates
c. Raise the energy input
d. Lower the energy input
3. The active site of an enzyme is complementary to
a. One type of substrate molecule
b. All types of substrate molecule
c. One type of product molecule
d. All types of product molecule
4. The graph shows the effect of temperature on the enzyme pepsin.
Between which two temperatures is there the greatest increase in enzyme activity?
a. 0-10 ⁰C
b. 10-20 ⁰C
c. 20-30 ⁰C
d. 30-40 ⁰C
5. Which of the following correctly describes amylase?
a. It breaks down starch into amino acids
b. It builds up glucose-1-phosphate into starch
c. It breaks down proteins into peptides
d. It breaks down starch into maltose
Questions 6, 7 and 8 refer to the following information below.
An investigation into the effect of pH on the digestion of milk by an enzyme was carried out.
Five identical dishes were set up with wells cut out of the agar.
To each well was added 5cm3 of the enzyme kept at a different pH as shown on the diagram below.
The dishes were kept at 35°C
The diameter of the area cleared by the action of the enzyme was measured.
6. The average diameter cleared at pH 5 was
a. 3mm
b. 4mm
c. 5mm
d. 6mm
7. The variable altered in this investigation was
a. Temperature
b. Diameter of the well
c. pH
d. milk concentration
8. The pH at which the enzyme was most active was
a. 3
b. 5
c. 7
d. 9
9. Which of the graphs below shoWs the effect of increasing temperature on enzyme activity?
10. Which line in the table below correctly shows the functions of an enzyme?
11. The diagram below shows three stages X, Y and Z that occur when an enzyme converts its substrate to a product.
This enzyme promotes the breakdown of a complex molecule into simpler molecules.
a) Put the stages into the correct order to show this degradation reaction
b) Which number in the diagram represents the active site
c) Describe what happens when an enzyme is denatured
12. The diagram below shows the action of the enzyme phosphorylase in a potato cell
a) Copy the sentence below, choosing the correct option in the bracket to make the sentence correct.
The action of the enzyme phosphorylase catalyses the degradation/ synthesis of starch.
b) State the effect of phosphorylase on the rate of this reaction.
c) Explain why lipase could not produce starch in this reaction.
