Question

a. How do the structures of cholic acid and chenodeoxycholic acid differ?

b. Are the three OH groups of cholic acid axial or equatorial?

Short answer

1. Cholic acid contains three hydroxyl groups and chenodeoxycholic acid contains two hydroxyls group.
2. Three hydroxyls are axial in position.

Step-by-step solution

Cholic and chenodeoxycholic acid

They both are the drive of bile salts that are synthesized in the liver and stored in the gall bladder and secreted into the small intestine and used in the emulsification of fates, and digested by water-soluble digestive enzymes.

The only difference in the structure is the presence of hydroxyl as cholic acid contains three hydroxyls and chenodeoxycholic contains two hydroxyl groups that the hydroxyl group at the C12 position is absent. This is why called deoxy.

Cholic and chenodeoxycholic acid

-OH of cholic acid

Cholic acid contains a dashed line below the plane represents three hydroxyl groups, and they all are axial in position because they all make a 90° angle with the plane. If they make the angle less than 90°, then equatorial in position.

Cholic acid