GCSE Biology - Enzymes - How Temperature and pH Affect Rate of Reaction

The video explains how temperature and pH affect enzyme activity. It shows that increasing temperature initially increases reaction rates due to higher kinetic energy, but excessive heat leads to enzyme denaturation. The optimal temperature for most enzymes is around 37°C. Similarly, pH levels that are too high or too low can denature enzymes by altering their active sites. Enzymes have specific optimal pH levels depending on their environment, such as a pH of 7 for most body enzymes and 2 for stomach enzymes.

What happens to enzymes when the temperature exceeds their optimal level?

• They remain unaffected.

• They speed up the reaction indefinitely.

• They change shape and may become denatured.

• They become more efficient.

What is the term used to describe the temperature at which an enzyme's reaction rate is highest?

• Critical temperature

• Peak temperature

• Maximum temperature

• Optimum temperature

How does a change in pH affect enzyme activity?

• It always increases the rate of reaction.

• It can cause the enzyme to become more stable.

• It has no effect on enzyme activity.

• It can alter the enzyme's shape, affecting its activity.

What is the optimal pH for most enzymes in the human body?

• Around 7

• Around 5

• Around 9

• Around 2

Why do enzymes in the stomach have a different optimal pH compared to those in the rest of the body?

• They are exposed to higher temperatures.

• They need to function in an acidic environment.

• They are less sensitive to pH changes.

• They are more efficient at neutral pH.