IGCSE Quiz - 13 May | Take the Quiz

Enzymes catalyse reactions by

Lowering activation energy of the reaction

Lowering activity energy of the reaction

Lowering physical energy of the reaction

Lowering chemical energy of the reaction

Fats is digested by lipase into fatty acid and glycerol. Which of the following is correct?

Key = Lipase, Lock = Fats

Key = Fats, Lock = Lipase

Key = Fatty acid and glycerol, Lock = Fats

Key = Fats, Lock = Fatty acid and glycerol

Which of the following is correct about Lock and Key hypothesis?

Substrate's shape is complementary to that of enzyme and fits exactly

Substrate's shape is complementary to that of enzyme but does not fit exactly

Substrate's shape is not complementary to that of enzyme

Substrate's shape is complementary to that of enzyme and fits exactly, causing enzyme to change shape

Which of the following is correct about Induced Fit hypothesis?

Substrate's shape is complementary to that of enzyme and fits exactly

Substrate's shape is complementary to that of enzyme but does not fit exactly. Enzyme will change shape to fit substrate more tightly

Substrate's shape is not complementary to that of enzyme

Substrate's shape is complementary to that of enzyme and fits exactly, causing enzyme to change shape

The diagram shows how enzyme activity varies with temperature. Describe what happens in region D.

Enzymes are denatured

The bonds that give enzymes their unique shape are broken

Beyond the optimum temperature, rate of reaction decreases as temperature increases

Beyond the optimum temperature, activation energy decreases

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