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Item 11 refers to the figure below which 12. Na and K cannot pass freely into a cell
shows part of the cell-surface membrane of across the phospholipid bilayer because
a red blood cell.
(A) they are repelled by the charged
cytoplasm
(B) they are too large to pass
(C) of the hydrophobic nature of the layer
(D) they are moving against a
concentration gradient

13. Amylase found in germinating seeds is
incubated with starch at 25 C and pH 2.
0
When a sample is removed after five minutes
and mixed with a solution of iodine in
potassium iodide solution, the mixture turns
to a blue-black colour. The MOST likely
explanation for this observation is
11. Molecule Z acts as a carrier to transport
selected substances across the membrane. (A) all the starch has been hydrolysed to
Which of the following substances is MOST
maltose
readily transported by this carrier molecule?
(B) a specific inhibitor of the amylase is
present
(A) Fructose
(C) amylase does not catalyse the
(B) Water hydrolysis of starch at 25 C
0
(C) Glucose
(D) the pH is too low for the reaction to
(D) Carbon-dioxide
proceed quickly

Item 14 refers to the graph below which shows the rate of an enzyme catalysed reaction with and
without inhibitors.

14. Which of the following sequences describes the types of reaction shown by Graphs I, II and III?

Graph I Graph II Graph III

(A) Competitive inhibitor Non-competitive inhibitor No inhibitor
(B) Competitive inhibitor No inhibitor Non-competitive inhibitor
(C) No inhibitor Competitive inhibitor Non-competitive inhibitor
(D) No inhibitor Non-competitive inhibitor Competitive inhibitor

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02107010/SPEC 2017