MCQ-2: Enzymes

Which effect does a gradual decrease in pH from 13 to 1 have on the action of amylase?

An enzyme in potato cells causes oxygen to be produced from hydrogen peroxide.
Cubes of potato were incubated with hydrogen peroxide at different temperatures.
The numbers of bubbles of oxygen released per minute were counted at each temperature.
The table shows the results.

The results suggest the optimum temperature for the enzyme is between which two values?

Which graph shows the effect of temperature on the activity of an enzyme?

The diagram represents enzyme action.

What are parts W, X and Y in this chemical reaction?

A food stain on a table cloth is where meat cooked in oil has been spilt.
It is washed in a biological washing powder.
Which combination of enzymes should be in the washing powder to remove the stain?

The graph shows how enzyme activity is affected by temperature.

How can the change in activity between 40 °C and 55 °C be explained?

The graph shows the effect of pH on the activity of three different enzymes.

The table shows the pH of different parts of the alimentary canal.

Which enzymes in the graph are likely to be protease enzymes?

An experiment was carried out to study the effect of temperature on the time taken for protein to be digested by an enzyme.
The table shows the results.

For these results, at which temperature does the enzyme denature?

Which statement describes the effect of temperature on enzymes?

An experiment was carried out to investigate the effect of pH on enzyme action. The graph shows the results.

What are the labels for the x-axis and the y-axis?

The diagrams show a protease enzyme catalysing the breaking of part of a protein molecule into smaller pieces.
Which diagram has three correct labels?

Six test-tubes were set up at different temperatures. Each contained identical solutions containing starch and amylase mixtures. The table shows the time taken for the reactions to finish in each test-tube.

At which temperature does the amylase work best?

Two enzyme-controlled reactions are shown.

From these reactions, what deduction can be made about enzymes?

A human digestive enzyme breaks down its substrate at a fast rate at 35 °C.
What would occur if the enzyme and substrate were kept at 75 °C?

The diagram shows the action of amylase.

What is the function of the enzyme amylase?

The graph shows the effect of pH on the rate of reaction of three different enzymes.

What does the graph show?

Some plants digest insects and use the nutrients for growth.
What must these plants produce to digest the insects?

Which statement is correct for all catalysts?

What happens to most enzymes above 60°C?

What is true of all enzymes?

• Option A
• Option B
• Option C
• Option D