IB Biology HL 1.1.8 Effects on Enzyme Activity

Practise analysing enzyme-kinetics data at HL depth, including immobilised enzymes, active-site changes, optimum conditions and experimental limits in temperature, pH and…

Exam points

Interpret enzyme-kinetics graphs to compare optimum conditions, saturation and denaturation.
Explain how pH, temperature and immobilisation alter active-site structure and reaction rate.
Evaluate experimental conclusions using controls, uncertainty and evidence from enzyme data.

[Maximum number: 3]

Cholinergic synapses use acetylcholine as their neurotransmitter. They are widespread in the body, passing on signals to muscle cells. These synapses are affected by neonicotinoid pesticides.

The diagrams, which are not drawn to scale, show the synapse between two neurons and a detail of the synaptic cleft.

Figure for Question C1.1.8—Effects on enzyme activity question 1 — IB Biology HL

Explain what happens to an enzyme if there is a change of pH .

a. change in pH can cause a change in the tertiary structure of the enzyme OR enzyme denatured

b. causing a change in the active site / substrate not able to bind $\boldsymbol{}$

c. the enzyme will not work as efficiently / decreased rate of reaction

d. (may no longer be) the optimum/optimal pH for enzyme activity

Marking guidance:

Allow answer in the form of a graph.

3 max

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C1.1.8—Effects on enzyme activity question 1