Digestive System and Enzymes Quiz
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5 questions, one answer each
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1. Which enzyme breaks down proteins into amino acids?
- A. Amylase
- B. Lipase
- C. Protease
- D. Carbohydrase
2. Where is bile produced?
- A. Pancreas
- B. Liver
- C. Small intestine
- D. Stomach
3. A student adds Biuret reagent to a food sample and it turns purple. What does this show?
- A. The food contains starch
- B. The food contains sugar
- C. The food contains protein
- D. The food contains fat
4. Why does emulsifying fat with bile speed up digestion by lipase?
- A. It lowers the pH of the fat
- B. It increases the surface area of the fat for lipase to act on
- C. It converts fat directly into fatty acids
- D. It destroys the fat molecules
5. In an investigation into amylase and pH, a student times how long it takes for iodine to stay orange-brown at pH 5, 7 and 9, keeping temperature and amylase/starch concentration constant. At pH 7 the time taken is shortest. What can be concluded, and why must temperature be controlled?
- A. pH 7 is optimum for amylase; temperature must be controlled so it does not also affect rate, hiding the effect of pH
- B. pH has no effect on amylase; temperature was the only relevant variable
- C. pH 9 is optimum because it took longest; temperature does not affect enzymes
- D. The iodine reagent itself sets the optimum pH for amylase