SAT Subject Biology Practice Question 6: Answer and Explanation
1. Which of these BEST describes the part of the molecule shown?
A. It is hydrophilic.
B. It forms the outer layer of the plasma membrane.
C. It is composed of phosphate atoms.
D. It contains nonpolar covalent bonds.
E. It is capable of hydrogen bonding.
Correct Answer: D
The lipid tails of a phospholipid molecule are indicated. This region of the phospholipid is hydrophobic (water avoiding), lacks phosphate atoms, contains nonpolar covalent bonds, and does not participate in hydrogen bonding. It forms the inner layer of the plasma membrane.