Lipids (1) Flashcards
How do you test for lipids?
1) dissolve solid samples in ethanol
2) add equal volume of water and shake
3) positive result = milky white emulsion forms
How are triglycerides formed?
condensation reaction between 1 glycerol molecule and 3 fatty acids forms an ester bond
What are 4 differences between saturated and unsaturated fatty acids?
1) S contain only single bonds, US contain double carbon bonds
2) S straight-chain molecules have many contact points, US ‘kinked’ molecules have fewer contact points
3) S higher melting point = solid at room temperature, US lower melting point = liquid at room temperature
4) S found in animal fats, US found in plant oils
What are the 4 structures of triglycerides related to their functions?
1) high energy : mass ratio = energy storage
2) insoluble hydrocarbon chain = no effect on water potential of cells + used for waterproofing
3) slow conductor of heat = thermal insulation
4) less dense than water = buoyancy of aquatic animals
What are the 2 functions of phospholipids?
- forms phospholipid bilayer in water = component of membranes
- tails can spray outwards = waterproofing
What is the structure of phospholipids?
Have a glycerol backbone attached to 2 hydrophobic fatty acids tails and 1 hydrophilic polar phosphate head
What are 4 similarities of phospholipids and triglycerides?
1) glycerol backbone
2) may be attached to a mixture of saturated, monosaturated and polyunsaturated fatty acids
3) contain carbon, hydrogen and oxygen
4) formed by condensation reactions
What are 3 differences between phospholipids and triglycerides?
1) P = 2 fatty acids + 1 phosphate group attached, T = 3 fatty acids attached
2) P = hydrophilic head and hydrophobic tail, T = entire molecule is hydrophobic
3) P = used primarily in membrane formation, T = used primarily as a storage molecule
What are triglycerides and phospholipids not, and why?
not polymers because they are not made from a small, repeating unit
What are triglycerides and phospholipids?
macromolecules ( + lipids)
