Question

multiple choice question
the structure of a phospholipid can best be described as which of the following?

glycerol joined to 3 fatty acids and a phosphate group
a 5-carbon sugar joined to a nitrogenous base and a phosphate group
five interlocking carbon rings joined to a phosphate group
glycerol joined to 2 fatty acids and a phosphate group
a 5-carbon sugar joined to a nitrogenous base and 2 phosphate groups

Explanation:

To determine the structure of a phospholipid, we recall:

• A phospholipid has a glycerol backbone.
• It is joined to 2 fatty acid chains (hydrophobic tails) and a phosphate group (hydrophilic head).
• Analyzing options:
• "Glycerol joined to 3 fatty acids..." is a triglyceride, not phospholipid.
• "A 5 - carbon sugar..." describes a nucleotide, not phospholipid.
• "Five interlocking carbon rings..." describes a steroid, not phospholipid.
• "A 5 - carbon sugar joined to...2 phosphate groups" is not a phospholipid structure.
• "Glycerol joined to 2 fatty acids and a phosphate group" matches the phospholipid structure.

Answer:

Glycerol joined to 2 fatty acids and a phosphate group