Final answer:
The correct answer is c) Phospholipids. These are the components of the plasma membrane that consist of a glycerol backbone with two fatty acids and a phosphate group, playing a crucial role in regulating molecule flow in and out of cells.
Step-by-step explanation:
Phospholipids are triesters of glycerols that contain charged phosphate diesters. They are a major constituent of the plasma membrane of cells. Unlike triglycerides, which have three fatty acid chains attached to the glycerol, phospholipids have two fatty acids forming diacylglycerol and the third carbon of the glycerol backbone is occupied by a modified phosphate group. This structure allows them to form lipid bilayers, which help to control the flow of molecules into and out of cells. Therefore, the correct answer is c) Phospholipids.They are important components of the plasma membrane of cells, helping to control the flow of molecules into and out of cells. Phospholipids consist of a glycerol unit with fatty acids attached to the first two carbon atoms, while a phosphoric acid unit, esterified with an alcohol molecule, is attached to the third carbon atom of glycerol. Examples of phospholipids include phosphatidylcholine and phosphatidylserine.