AFL Enzymes

Which of the following best describes what an enzyme is?

• A catalyst that speeds up reactions in cells, being used up in the process.

• A protein that speeds up reactions in cells, being used up in the process.

• A carbohydrate that functions as a biological catalyst.

• A protein that functions as a biological catalyst.

What is a feature of all catalysts?

• They are made from protein

• They are not changed by the reaction

• They are broken down in the reaction

• They are altered by the rate of the reaction.

What can be said to be true to all enzymes?

• A

• B

• C

• D

Which graph in the image below shows the correct effect of temperature on the activity.

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The image below represents a chemical reaction. Which of the following best represents the enzyme responsible for catalysing the reaction?

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The action of an enzyme in a chemical reaction is outlined in the diagram below. Which row of the table is correct.

• A

• B

• C

• D

The pH of an enzyme controlled reaction is decreased by a pH of 2. How does this affect the rate of the reaction?

• It has no effect on the rate

• It always decreases the rate

• It always increases the rate

• It may increase or decrease the rate

Temperature affects the rate of all enzyme-controlled reactions, as shown in the graph below

• A

• B

• C

• D

The effect of pH on the rate of reaction of three different enzymes is shown in the graph below. What does the graph show?

• each enzyme works best over a narrow temperature range

• Most enzymes work best around a neutral pH

• Enzymes work better in acidic conditions

• Each enzyme works best at a different pH

The diagram below show an amylase enzyme catalysing the breakdown of part of a starch molecule into smaller molecules of maltose. Which diagram has three correct labels?

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