Lipids

• Saturated fatty acids have only single bonds between carbons
• Unsaturated fatty acids - hydrocarbon chain that has at least one double bond between carbons
• Lipids are used for:

  • Energy store/source for respiration
  • Thermal insulation
  • Electrical insulation
• Lipids contain carbon,hydrogen and oxygen atoms
• Lipids are insoluble in water
• Lipids are non-polar molecules (not charged)
• Triglycerides are insoluble in water
• Triglycerides are compact for storage
• Lipids are not polymers as they're made up of carbon,hydrogen and oxygen
• phospholipids have a polar, hydrophilic head
• phospholipids make up 75% of cell membranes
• Phospholipids have non-polar, hydrophobic tails
• Unsaturated fatty acids are more permeable and fluid
• Bilayers form in membranes as phospholipid heads and tails do not mix
• Cholesterol is a small lipid formed of four carbon-based rings
• Cholesterol forms the basis of steroid hormones and regulates membrane fluidity