Answer to Question #112720 in Cell Biology for Judy

Question

Explain how phospholipids and steroids differ in structure from fats. Make sure you discuss all 3 lipids.

Answer 1

Fats refer to an oily substance that occurs in the body under the skin or around the organs. Since the degree of saturation of fatty acids is high, fats are typically solid at room temperature. The unsaturated fat is known as oils, which are liquids at room temperature. Typically, fats have an animal origin, and oils have a plant origin. The two types of fats are the saturated fat and the trans fat.

Lipids refer to a class of organic molecules that are insoluble in water and soluble in organic solvents. They are a diverse group of molecules. Most of the lipids are liquids. However, some lipids such as fats are solids. The three major types of lipids are triglycerides, phospholipids, and steroids. The largest class of lipids is triglycerides.

Triglycerides are also called natural fats. They are esters, containing a single glycerol molecule which is attached to three fatty acid molecules. Based on the degree of saturation of the fatty acid molecules, two types of triglycerides can be identified as fats and oils. The unsaturated form of triglycerides is known as oils, and the saturated form of triglycerides is known as fats. The major function of triglycerides in the body is to serve as ener

gy-storing molecules.

Phospholipids are a derivative of triglycerides since they contain two fatty acid molecules. The third carbon of the glycerol molecule is attached to a phosphate group.

Thereby , phospholipids are amphipathic molecules in which the diglyceride part is hydrophobic while the phosphate group is hydrophilic. Phospholipids are the main structural component of the cell membrane, and they form the phospholipid bilayer. The phospholipid molecules

make the cell membrane a selectively permeable barrier.

Steroids are a type of hydrophobic molecules mostly found as cholesterol and hormones. Cholesterol is the precursor of other types of steroids in the body.