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Question 18M.2.SL.TZ2.4b

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Date May 2018 Marks available [Maximum mark: 3] Reference code 18M.2.SL.TZ2.4b
Level SL Paper 2 Time zone TZ2
Command term Explain Question number b Adapted from N/A
b.
[Maximum mark: 3]
18M.2.SL.TZ2.4b
(b)

Explain enzyme–substrate specificity.

 

[3]

Markscheme

a. enzymes are proteins with specific 3-D geometry/shape 

b. enzymes with active site that binds with the substrate/reactants 

c. active site shape only allows it to bind with specific substrates «with complementary shapes» 

d. when enzyme-substrate complex formed allows reaction to occur 

e. products are released and enzyme returns to original shape and can be reused
OR
denaturing changes shape «of active site» so changes ability to bind with substrate

Accept marks from clear annotated diagrams.

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