Chapter 6 - Lipids Objectives

  1. Know the building blocks for lipids

    • Fatty acids and glycerol

      • fatty acids are long chains of carbon atoms

      • glycerol is a three-carbon alcohol molecule with 3 hydroxyl groups

  2. Name the type of linkage associated with lipids

    • Ester linkage

      • Adding a fatty acid through dehydration reaction makes a triglyceride (stores energy) which makes an ester linkage and a carbonyl

  3. Understand the reaction that attaches building blocks to the macromolecules and how it can be reversed

    • Dehydration synthesis/condensation reaction

      • monomers polymerize through this

      • a chemical reaction in which two molecules are joined covalently with the removal of an —OH from one and an —H from another to form water

    • Hydrolysis

      • a chemical reaction in which a molecule is split into smaller molecules by reacting with water, most involve splitting of polymers into monomers

        • adding a water molecule

        • water molecule reacts with the bond linking the monomers separating one monomer from the polymer chain

  4. Be able to explain how the number of carbons and type of bonds within the fatty acid affect the characteristic of the lipid

  5. Identify the different types of lipids and functions in the cell

    • Steroids, Fats, Phospholipids

      • don’t polymerize or make chains

      • characteristic: non-polar or hydrophobic and have hydrocarbons

    • Steroids

      • distinguished by a 4 fused ring carbon skeleton, attached to carbons in the ring

    • Fats

      • composed of three fatty acids linked to a glycerol molecule, also called triglycerides, primary role is to store energy, form by a dehydration reaction (a hydroxyl group of glycerol and the carboxyl group of a fatty acid), glycerol and fatty acid molecules become joined by an ester linkage

    • Phospholipids

      • consist of a glycerol linked to two fatty acid tails and a phosphate group with an ester linkage

        • hydrophilic head that contains glycerol and a hydrophobic tail that is composed of two non-polar fatty acids

      • in bacteria and eukarya, isoprenoids in archaea

      • primary role is to form a lipid bilayer of all cell membranes which creates a protective semi-permeable barrier that regulates the passage of substances into and out of the cell

  6. Explain the amphipathic nature of phospholipids

    • when amphipathic lipids are placed in water the hydrophilic heads interact with water, the hydrophobic tails interact with each other away from the water

      • forms lipid micelles and lipid bilayers

  7. Discuss which types of molecule would be permeable through the lipid membrane

  8. Explain the factors that can alter membrane permeability

  9. Know the structure of cholesterol and how it impacts both permeability and fluidity

  10. Explain the setup and the trends associated with figure 6.10