Question 1: Enzymes are biological catalysts that speed up chemical reactions in the body without being consumed. They work by lowering the activation energy required for reactions to occur, often through a specific active site that binds to substrate molecules.

Answer: Enzymes are biological catalysts that lower activation energy and work via active sites that bind specific substrates.

Question 1: Define the term 'enzyme specificity'.

Answer: Enzyme specificity refers to the ability of an enzyme to catalyse a specific reaction or act on a particular substrate due to the shape of its active site.

Question 2: Explain how temperature affects enzyme activity, including what happens when temperatures are too high or too low.

Answer: Enzyme activity increases with temperature up to an optimum point because molecular movement speeds up. When temperatures are too high, enzymes denature and lose their shape, decreasing activity. Too low temperatures slow down molecular movement, reducing enzyme activity.

Question 1: If an enzyme catalyses 1200 reactions in 10 minutes under optimal conditions, calculate the rate of reaction in reactions per minute.

Answer: Rate = Total reactions / Time = 1200 reactions / 10 minutes = 120 reactions per minute.

Question 2: A substrate concentration of 5 mM results in an enzyme activity of 600 reactions per minute. If the substrate concentration is increased to 10 mM, and the new activity is 900 reactions per minute, calculate the percentage increase in enzyme activity.

Answer: Percentage increase = ((900 - 600) / 600) × 100 = (300 / 600) × 100 = 50%.

Question 1: Describe a basic experiment to test the effect of pH on enzyme activity. Include the variables you would control and variables you would measure.

Answer: The experiment involves keeping a fixed amount of enzyme and substrate constant while varying the pH of the solution. Measure the rate of reaction at each pH level, such as by recording the time taken for a reaction to complete or the amount of product formed. Control variables include temperature, enzyme concentration, and substrate concentration.

Question 2: Identify two safety precautions that should be followed when handling enzymes and chemicals in the laboratory.

Answer: Wear appropriate protective equipment such as gloves and goggles; handle chemicals carefully to avoid spills and ingestion.

Question 1: A study measures enzyme activity at different temperatures. The data shows maximum activity at 37°C, with reduced activity at 25°C and 50°C. Explain why enzyme activity is highest at 37°C and decreases at higher temperatures.

Answer: Enzyme activity is highest at 37°C because this is close to the human body's normal temperature, providing optimal kinetic energy for reactions. At higher temperatures like 50°C, enzymes denature and lose their shape, reducing activity. At lower temperatures, molecular movement is slower, decreasing the rate of reaction.

Question 1: Discuss the importance of enzymes in industrial applications, such as in the production of biofuels or pharmaceuticals. Include potential advantages and challenges.

Answer: Enzymes are crucial in industry for their ability to catalyse specific reactions efficiently under mild conditions, reducing energy costs. In biofuel production, enzymes break down biomass into sugars for fermentation. In pharmaceuticals, enzymes are used in drug synthesis. Challenges include enzyme stability, cost of production, and potential environmental impacts.

Question 2: Multiple Choice: Which of the following factors does NOT directly affect enzyme activity?

Answer: Colour of the solution