Question

1. when placed in water, oil does not dissolve and stays separate. this means oil is_____ and _____

a. hydrophilic and polar

b. hydrophilic and nonpolar

c. hydrophobic and polar

d. hydrophobic and nonpolar

1. as food travels through the digestive system, it is exposed to a variety of ph levels. the stomach has a ph of 2 due to the presence of hydrochloric acid (hcl), and the small intestine has a ph ranging from 7 to 9. hcl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. which of the following most likely happens to pepsin as it enters the small intestine?

a. it becomes inactive.

b. it begins to replicate.

c. its shape changes to engulf large proteins.

d. its activity increases to digest more proteins.

Explanation:

For question 7: Hydrophobic substances do not dissolve in water and non - polar molecules do not interact well with polar water molecules. Oil does not dissolve in water, so it is hydrophobic and non - polar.
For question 23: Enzymes are pH - sensitive. Pepsin is active in the acidic environment of the stomach (pH 2). The small intestine has a basic pH (7 - 9). Pepsin will become inactive in the basic environment of the small intestine as the pH is not optimal for its function.

Answer:

1. d. Hydrophobic and nonpolar
2. a. It becomes inactive.