Download Enzyme HW

DO BOTH SIDES!
Name _________________________
Enzyme Questions – Homework
1. The table below lists enzymes that function in different locations in the human body, and the
temperature and pH ranges of these locations.
Different enzymes are secreted in each of the three locations. Ptyalin digests carbohydrates. Pepsin
and trypsin both digest proteins. Discuss the activity of these enzymes. Answer the following:
a. state how the activity of pepsin will most likely change after it moves with the food from the
stomach to the small intestine – support your answer using data from the table
b. state how a fever of 40ºC would most likely affect the activity of these enzymes and support
your answer
c. identify the characteristic of enzymes that prevents ptyalin and trypsin from digesting the
same type of food
2. When an apple is cut open, the inside soon turns brown. This is because enzymes that are released
from the cut cells react with certain molecules in the apple. Rubbing lemon juice (which contains
citric acid) on the cut apple prevents it from browning. Explain why this is so.
DO BOTH SIDES!
3. Fresh pineapple contains an enzyme that digests proteins. Adding fresh pineapple to gelatin (a
protein) prevents it from setting or jelling. Adding cooked or canned pineapple does not have this
effect and the gelatin can set normally. Explain why these different effects occur.
4. The human stomach contains an enzyme called pepsin, which actively breaks down (digests) protein
molecules found in food. Based on your knowledge of biology, answer the following:
a. At what temperature would you expect pepsin to work best? Give a reason.
b. At what pH would you expect pepsin to work best? Give a reason.
c. Why would drinking very cold beverages have a negative effect on digestion of food in the
stomach?