Enzyme Activity and Function Concepts

This video from IGCSE Study Buddy covers enzymes, their role as biological catalysts, and their importance in metabolic reactions. It explains how enzymes function, emphasizing the lock and key mechanism and enzyme specificity. The video also discusses factors affecting enzyme activity, such as temperature and pH, and provides examples of enzymes with different optimal conditions. Viewers will learn about enzyme-substrate interactions and the conditions that can denature enzymes, affecting their functionality.

What is the primary role of enzymes in living organisms?

• To change the products of reactions

• To be consumed in reactions

• To increase the rate of chemical reactions

• To provide energy for reactions

Which of the following best describes a substrate?

• A molecule that changes the enzyme

• A molecule on which an enzyme acts

• A molecule that is produced after a reaction

• A molecule that speeds up reactions

What is the 'lock and key' mechanism in enzyme activity?

• The enzyme changes shape to fit the substrate

• The substrate changes shape to fit the enzyme

• The enzyme and substrate have complementary shapes

• The enzyme is consumed in the reaction

How does temperature affect the rate of an enzyme-catalyzed reaction?

• The rate is highest at low temperatures

• The rate increases as temperature increases

• The rate remains constant regardless of temperature

• The rate decreases as temperature increases

What happens to an enzyme if the temperature is too high?

• It becomes more active

• It gets denatured

• It remains unchanged

• It changes the substrate

At what temperature do most human enzymes start to denature?

• 60 degrees Celsius

• 50 degrees Celsius

• 40 degrees Celsius

• 37 degrees Celsius

What is the optimum pH for the enzyme pepsin?

• 8

• 2

• 7

• 10

Which enzyme works best at a pH of 7?

• Protease

• Lipase

• Amylase

• Pepsin

What happens to an enzyme if the pH deviates too much from its optimum?

• It gets denatured

• It remains unchanged

• It becomes more active

• It changes the substrate

Which of the following is NOT a factor affecting enzyme activity?

• Light intensity

• Substrate concentration

• pH

• Temperature