Final answer:
Lipids are nonpolar, hydrophobic macromolecules different from proteins, carbohydrates, and nucleic acids. They include fats, oils, waxes, phospholipids, and steroids, playing key roles in energy storage, insulation, membrane structure, and hormone synthesis.
Step-by-step explanation:
How Lipids Differ from Other Macromolecules
Lipids are a distinct class of macromolecules that are largely nonpolar and hydrophobic, making them different from other macromolecules such as proteins, carbohydrates, and nucleic acids. While proteins are polymers of amino acids, and nucleic acids are chains of nucleotides, lipids are composed primarily of hydrocarbons. The most common lipids include fats and oils, waxes, phospholipids, and steroids.
Fats, also known as triglycerides or triacylglycerols, are a stored form of energy and are composed of fatty acids bound to glycerol or sphingosine. Phospholipids are key components of cell membranes, consisting of two fatty acid chains and a phosphate group attached to a glycerol or sphingosine backbone. Steroids, distinguished by their four fused carbon rings, are vital in the structure of cell membranes and as precursors to hormones such as testosterone.
Saturated fatty acids contain no double bonds and are 'saturated' with hydrogen, whereas unsaturated fatty acids have one or more double bonds in their hydrocarbon chain. These structural differences affect their physical state at room temperature, with fats typically being solid and oils being liquid. These properties make lipids important for energy storage, insulation, cellular membrane structure, and hormone synthesis.