3. Lipids and transport

• What are triglycerides

  Glycerol and 3 fatty acids
• What is a saturated fatty acid

  Has no carbon to carbon double bonds
• What is an unsaturated fatty acid

  Has one or more carbon to carbon double bond
• What bind forms in lipids

  Ester bond
• What are some roles of triglycerides

  Energy storage

  insulation

  protection of organs
• How is the structure of triglycerides related to function

  Low mass to energy ratio making them good storage molecules

  large And insoluble so have no osmotic effect

  high ratio of energy storing carbon-hydrogen bonds to carbon atoms and therefore good source of energy
• What are phosphollipids

  2 fatty acid chains and phosphate and glycerol
• What is the head of a phospholipid

  Hydrophilic - attract water
• What are the tails of a phospholipid

  Hydrophobic- repels water
• How to test for lipids

  Ethanol emulsion test

  add ethanol and shake

  add water and shake

  if a milky white emulsion forms a lipid was present
• What are the 3 functions of a plasma membrane

  Control the transport of substances

  act as a receptor site

  separate cell from environment
• What do membranes not let through

  polar, water soluble molecules
• What does the bilayer allow to pass through

  Lipid soluble and non polar molecules
• What are membrane proteins

  Can be intrinsic or extrinsic

  used for active transport and facilitated diffusion.
• What are glycoproteins and what do they do

  Short branching carbohydrate chains are attached to a protein.

  act as receptors for hormones and neurotransmitters
• What are glycolipids

  A carbohydrate chain attached to a lipid they maintain stability of membrane by making them less flexible - prevents water loss
• What is cholesterols role in a bilayer

  Affects membrane fluidity - more cholesterol equals less fluid.
• Why is the bilayer knows as a fluid mosaic model

  Fluid - all different molecules can move around

  mosaic - lots of different types of molecules
• Diffusion and osmosis are passive what does this mean

  Does not require ATP
• What is simple diffusion

  Movement of substances down a concentration gradient through the phospholipid bilayer.
• What is facilitated diffusion

  Down a concentration gradient but has to use a channel protein. The tubes of the protein will fill with water and allow them through or change shape
• What is osmosis

  Movement of water from an area Of higher water potential to low water potential across a bilayer
• What is a hypertonic solution

  Low water potential (concentrated)
• What is a hypotonic solution

  High water potential
• What is an isotonic solution

  Same water potential
• What happens to an animal cell in a hypertonic solution

  Water leaves the cell by osmosis causing it to crenate
• What happens to an animal cell in hypotonic solution

  Water enters the cell causing it to burst known as osmotic lysis
• Why do animal cells burst in hypotonic solutions

  They have no protective cell wall
• What happens to a plant cell in hypertonic solution

  Water leaves the cell causing the cytoplasm to shrink away from cell wall leaving gaps - plasmolysis
• What happens to a plant cell in a hypotonic solution

  Water enters causing the cell to become turgid
• What is active transport

  Movement against the concentration gradient. Cartier proteins will move the substance into the cell as ATP changes the shape of the carrier