Required Practical 1

Question 1

What is the independent variable in an enzyme-controlled reaction investigation?

Answer 1

• Enzyme concentration
• Substrate concentration
• pH
• Temperature
• Inhibitors

The independent variable is the factor that is changed to observe its effect on the reaction rate.

Question 2

What are some ways to measure the dependent variable in an enzyme-controlled reaction?

Answer 2

• Colour change (via colorimetry)
• Mass of substrate or product
• Bubble formation (if the substrate is a gas)

The dependent variable is the rate of reaction that is measured in various ways.

Question 3

What is the best way to control temperature in an enzyme investigation?

Answer 3

Use a thermostatically controlled water bath

Regular checks with a thermometer are necessary as temperature can fluctuate.

Question 4

What is a buffer in the context of enzyme investigations?

Answer 4

A solution that resists changes in pH

Buffers help maintain a stable pH during the reaction.

Question 5

In enzyme investigations, why is it important to control variables like concentration?

Answer 5

To ensure that only the independent variable affects the reaction rate

Using consistent volumes or concentrations helps isolate the effect of the independent variable.

Question 6

What is a control in enzyme investigations?

Answer 6

A setup that allows you to be sure of the results, often using a denatured enzyme or no enzyme at all

Controls help confirm that the observed effects are due to the enzyme and not other factors.

Question 7

True or false: In enzyme investigations, the controlled variables can include temperature, pH, and concentrations.

Answer 7

TRUE

Controlled variables must be kept constant to ensure valid results.