Biological molecules - Lipids

• What are triglycerides classified as?

  type of lipid.
• How can fatty acids be categorized?


  Fatty acids can be saturated or unsaturated.
• What is the function of triglycerides in animals and plants?

  mainly used as energy storage molecules.
• Why are triglycerides considered good for storage?


  1. High energy density (much energy per gram).
  2. Long hydrocarbon tails contain a lot of chemical energy.
  3. Insoluble, preventing water from entering cells by osmosis.
  4. Tails repel water, forming insoluble droplets.
• What are triglycerides made up of?

  three fatty acid long hydrocarbon tails and glycerol.

  ester bonding
• What structure do phospholipids form in cell membranes?

  form the phospholipid bilayer in cell membranes.

  hydrophilic head and hydrophobic tail
• What are the characteristics of phospholipids in the bilayer?

  1. Phospholipids have one hydrophilic heads and two hydrophobic tails.
  2. The head faces out towards the water on either side.
  3. The entire layer is hydrophobic, acting as a barrier to water-soluble substances.
• What is cholesterol classified as?

  type of lipid.
• What is the structure of cholesterol?


  hydrocarbon ring structure attached to a hydrocarbon tail.
• How does cholesterol function in cell membranes?

  • helps to regulate the fluidity of the membrane.
  • It interacts with phospholipids to maintain membrane stability.
  • Cholesterol's small size and flattened shape allow it to fit between phospholipids.
• What happens to cholesterol at higher and lower temperatures?

  At higher temperatures, cholesterol tends to pack together. At lower temperatures, cholesterol increases membrane fluidity.
• How are triglycerides broken and formed?


  formed - condensation reaction

  broken - hydrolysis reaction