Set 6 — Effect of Temperature & Graphs

What is the aim of the temperature enzyme experiment?

To investigate the effect of temperature on enzyme activity

What is the independent variable in the temperature experiment?

Temperature of the reaction mixture

How is temperature changed in the experiment?

By using water baths at different temperatures

What is the dependent variable in the temperature experiment?

Rate of enzyme activity measured by foam produced per minute

What variable is kept constant in the temperature experiment?

pH using a pH 9 buffer

What temperatures are shown in the experiment?

0 degrees Celsius and 10 degrees Celsius and 25 degrees Celsius and 40 degrees Celsius

What is the first step in the temperature experiment?

Add pH 9 buffer and washing-up liquid to a graduated cylinder

What is the second step in the temperature experiment?

Add blended celery filtrate to the graduated cylinder

What is the third step in the temperature experiment?

Place the graduated cylinder in a water bath at the chosen temperature

What starts the reaction in the temperature experiment?

Adding hydrogen peroxide

How is the temperature experiment repeated?

Repeat at different temperatures and measure foam produced per minute

What is optimum temperature?

The temperature at which an enzyme works at its maximum rate

What is optimum pH?

The pH at which an enzyme works at its maximum rate

What happens to enzyme activity as temperature increases towards the optimum?

The reaction rate increases due to more frequent successful collisions

What happens above the optimum temperature?

The enzyme begins to denature and the reaction rate decreases

What is denaturation?

A change in the enzyme's three-dimensional shape that alters its active site

What is the shape of a typical enzyme activity versus pH graph?

A peak at the optimum pH with lower activity on either side