Enzymes Quiz
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5 questions, one answer each
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1. What is the active site of an enzyme?
- A. The part of the enzyme that is broken down during the reaction
- B. The region with a shape complementary to the substrate, where the reaction takes place
- C. The outer membrane surrounding the enzyme
- D. A region that only proteins possess
2. Why does a very high temperature stop an enzyme working?
- A. The enzyme freezes and cannot move
- B. The active site changes shape as bonds break, so the substrate no longer fits
- C. The active site becomes bigger, allowing any substrate to bind
- D. The substrate evaporates before it can bind
3. Which reagent is used to detect starch during the amylase pH practical?
- A. Benedict's solution
- B. Biuret reagent
- C. Iodine solution
- D. Sudan III
4. An amylase reaction breaks down all starch after 25 seconds. What is the rate using rate = 1/time?
- A. 25 s⁻¹
- B. 0.4 s⁻¹
- C. 0.04 s⁻¹
- D. 2.5 s⁻¹
5. A student burns a food sample under 100 g of water, raising its temperature by 8°C. What is the energy transferred, and why might calorimetry underestimate true energy content?
- A. 3360 J; because heat is lost to the surroundings rather than transferred to the water
- B. 3360 J; because the water absorbs more energy than was released
- C. 840 J; because the food gains energy from the water
- D. 4.2 J; because only 1 g of water was heated