3.1.3 lipids Flashcards
what are triglycerides formed from?
- a glycerol group.
- 3 fatty acid chains.
- ester bond.
- condensation reaction.
how do triglycerides interact with water?
they are hydrophobic, therefore water hating.
are fatty acid chains in phospholipids and triglycerides saturated or unsaturated?
they can be either!
what effect does a saturated fatty acid chain have on a lipid?
no carbon-to-carbon double bonds, therefore a straight molecule.
what effect does an unsaturated fatty acid chain have on a lipid?
- has one or more carbon-to-carbon double bonds.
- this causes a bend in the molecule.
- this results in the molecule being less tightly packed, therefore fewer London forces are formed.
- resulting in a LOWER melting and boiling point.
what are phospholipids formed from?
- a glycerol group.
- a phosphate group (only phospholipids have the phosphate group).
- ester bond.
- 2 fatty acid chains.
how do phospholipids interact with water?
- they are amphipathic, therefore both hydrophobic and hydrophilic.
- the head of the phospholipid is hydrophilic and polar.
- the tail of the phospholipid is hydrophobic and non-polar.
what do phospholipids form due to their amphipathic qualities?
a bilayer.
how are triglycerides respistory substrates?
- many C-H groups, which can be oxidised and therefore release electrons, which can be used in ATP.
- high energy content (many bonds can be oxidised) = good respiratory substrate.
how are triglycerides waterproof?
hydrophobic so water molecules are repelled.
why are triglycerides poor electrical and thermal conductors?
- they are non-polar so cannot become charged.
- there are no delocalised electrons.
how can you test for lipids?
- add ethanol to a sample and shake.
- then add water.
- a white emulsion will form (milky) in the presence of a lipid.
