• elements present: C,H (,O)
• No monomer, but made of glycerol head and fatty acid tails
  • linked by ester bonds
• long hydrocarbon chains make lipids hydrophobic and generally nonpolar
• Functions:
  • energy storage
  • protection of vital organs
  • insulation
  • structure of cell membrane

Triglycerides (fats)

• glycerol head and 3 fatty acid tails
• Fatty Acids

  • Saturated: no double bonds between carbons

    • solid at room temp (butter, lard)
    • usually animal products

  • Unsaturated: some double bonds between carbons

    • double bonds bend the fatty acid
    • liquid at room temp (olive oil, vegetable oil, fish oil)
    • usually plant products

    

Phospholipids

• make up cell membrane in lipid bilayer
• when placed in water create liposome or micelle depending on quantity of phospholipids
• amphipathic: has polar and nonpolar areas
• glycerol (with phosphate) head is polar, hydrophilic
• 2 fatty acid tails are nonpolar, hydrophobic
• saturation of fatty acid determines structure function of lipid
• organisms in colder places need more unsaturated fatty acids so that they have more fluidity in cell membranes without it hardening too much, while organisms is hotter places are better without so many unsaturated fatty acids so that their cell membrane is not too fluid.

Steroids

• four carbon rings fused together