Lipids

Definition

Lipids are a diverse group of hydrophobic organic molecules essential for cell structure, energy storage, and signaling. They include fats, oils, waxes, phospholipids, and steroids.

5 Must Know Facts For Your Next Test

1. Lipids are key components of cell membranes, forming the bilayer that separates the interior of the cell from its environment.
2. Phospholipids have a hydrophilic head and two hydrophobic tails, making them crucial in membrane structure and function.
3. Steroids such as cholesterol play a role in membrane fluidity and serve as precursors for hormone synthesis.
4. Lipids store more energy per gram than carbohydrates or proteins due to their high proportion of carbon-hydrogen bonds.
5. Fatty acids can be saturated (no double bonds) or unsaturated (one or more double bonds), affecting their physical properties and biological roles.

Review Questions

• What is the primary structural role of lipids in cellular membranes?
• How do phospholipids contribute to the functionality of cell membranes?
• Why are lipids considered an efficient form of energy storage?

Related terms

Carbohydrates: Organic molecules composed of carbon, hydrogen, and oxygen that serve as a major energy source.

Proteins:

Large biomolecules made up of amino acids that perform a variety of functions within organisms.

Enzymes: Proteins that act as biological catalysts to accelerate chemical reactions in cells.