Question 1: Define an enzyme and explain its role in the digestive system.

Answer: An enzyme is a biological catalyst that speeds up chemical reactions, such as breaking down food molecules during digestion.

Question 2: Describe how enzymes lower the activation energy of reactions.

Answer: Enzymes lower the activation energy by providing an alternative reaction pathway, making it easier for molecules to react.

Question 3: What is the significance of enzyme specificity in digestion?

Answer: Enzyme specificity ensures that enzymes only catalyze specific reactions, such as amylase breaking down starch but not proteins.

Question 1: If an enzyme catalyzes the breakdown of 120 grams of starch in 30 minutes, what is the rate of enzyme activity in grams per minute?

Answer: Rate = Total starch broken down / Time = 120 g / 30 min = 4 g/min

Question 2: The optimal temperature for an enzyme is 37°C. If the enzyme activity decreases by 50% at 45°C, what is the activity at 45°C if the activity at 37°C is 100 units?

Answer: Activity at 45°C = 50 units (since it decreases by 50%)

Question 3: Calculate the enzyme efficiency if 200 units of substrate are broken down in 10 minutes by 2 units of enzyme. Express efficiency as units per enzyme per minute.

Answer: Efficiency = Total substrate breakdown / (Number of enzymes × Time) = 200 units / (2 × 10 min) = 10 units/enzyme/min

Question 1: Describe a basic experimental setup to test the effect of temperature on enzyme activity. Include variables to be controlled and safety precautions.

Answer: The experiment involves incubating a fixed amount of enzyme (e.g., amylase) with substrate (starch) at different temperatures. Control variables include pH, enzyme concentration, and substrate amount. Safety precautions include wearing gloves and eye protection when handling enzymes and hot water baths to prevent burns.

Question 1: A study shows that enzyme activity drops sharply beyond pH 8.0. Explain what this suggests about the enzyme's optimal pH and the importance of pH in enzyme activity.

Answer: This suggests the enzyme's optimal pH is around 8.0, and maintaining pH within this range is crucial for maximum enzyme activity.

Question 1: Explain how enzymes influence the rate of digestion in the human body. Include the concepts of activation energy and substrate specificity. (6 marks)

Answer: Enzymes increase the rate of digestion by lowering the activation energy required for chemical reactions, allowing these reactions to occur faster at body temperature. Their substrate specificity ensures that they catalyze only specific reactions, such as amylase breaking down starch into sugars, which enhances efficiency and regulation of digestion.

Question 1: Describe how enzymes are used in the food industry, providing at least two examples.

Answer: Enzymes are used to produce cheese and yogurt by fermenting milk, and to clarify juices by breaking down pectin.