2.2.6-14 biomols - lipids, proteins, inorganic ions Flashcards
lipids are only soluble in …
ORGANIC solvents
saturated lipids
- eg animal fats (solid)
- only c-c single bonds
unsaturated lipids
- eg plant oils (FOREXAMPLE SAY VEGETABLE OIL ) (liquid)
- c=c double bonds
unsaturated lipid melting point
LOWER
- double bond causes a kink in the chain
- molecules cant pack as closely together
- weaker imfs so lower mp
unsaturated lipid state (room temp)
liquid
saturated lipid state (room temp)
solid
triglycerides
lipids made of one glycerol headand 3 fatty acid tails
bond joining glycerol and fatty acids
ester bond
reaction where triglycerides are made
condensation
use of triglycerides
ENERGY STORAGE (plant + animals)
phospholipids
- one fatty acid of a triglyceride is replaced by a phosphate containing group
- glycerolhead, 2 fatty acid chains, 1 phosphate
phosphate head property…
HYDORPHILIC (as it is charged)
tail of phospholipid property
HYDROPHOBIC
hydrogen ion formula
H+
amino group
NH2
how many diff amino acids
20
- differ by their ‘R’ group
bond joining amino acids
PEPTIDE bond
reaction joining amino acids
condensation
primary structure (2)
-order and number of amino acids in a protein
- held together by PEPTIDE bonds
secondary structure
-REGULAR FOLDING of amino acid chain into repeating patterns
- either alpha helix or beta pleated
what bond holds together secondary structure
hydrogen bonding
tertiary structure of proteins
- SECONDARY IS COILED AND FOLDED FURTHER
-disulfide bridge, ionic, hydrogen bonds between R GROUPS !!!!!!!!! - FINAL 3D STRUCTURE OF AMINO ACIDS FROM 1 PPC
globular protein shape
highly folded - spherical
examples of fibrous (2)
- keratin
- collagen
example of globular (3)
- haemoglobin
- insulin
- enzymes
biuret test
- add BIURET
OR - sample + equal amount of NaOH
- add copper (II) sulphate solution and mix
- if positive, blue -> lilac
lipids test
- add ethanol and thoroughly shake
- add water
- if positive, colourless -> milky white
macromolecules
complex molecules with a high mr
lipids elements
carbon, hydrogen, oxygen
why are lipids insoluble in water
hydrophobic tail
break down of triglycerides reaction
hydrolysis
why are triglycerides good for storage (2)
- long HC tails of fatty acids contain lots of chemical energy. lipids contain 2x as much energy per gram as carbohydrates
- insoluble, dont change osmotic conditions.
where are phospholipids found
cell membranes of all eukaryotes and prokaryotes (phospholipid bilayer)
phospholipid bilayer
- phospholipid heads are hydrophilic, and tails hydrophobic, so they form a double layer with their heads facing out towards the water on either side
- centre of the layer is hydrophobic, so membrane is a barrier
cholesterol
4 ring structure
cholesterol size + shape
small size + flattened shape, so cholesterol can fit in-between phospholipid molecules of membrane
dipeptide
2 amino acids join together
amino acid elements
CHON(S)
Quaternary structure
- diff PPC held together by bonds
- the way the chains are assembled together
- eg haemoglobin from 4 PPCS
globular solubility and why
SOLUBLE (so easily transported)
- hydrophilic R groups pushed to the outside, hydrophobic on inside
- forms HB with water
haemoglobin
- globular
- carries oxygen around the body in RBCs
- 2 alpha 2 beta
- conjugated protein; EACH PPC SUBUNIT has a non protein (prosthetic) group attached - 4 prosthetics
- called, haem, which contains the single Fe2+ ion that oxygen binds to
are lipids polymers
NO
are lipids soluble
NO
- dont affect cell water potential , or osmosis
Lipid purposes (7)
- thermal insulation (blubber)
- electrical insulation (myelin sheath)
- energy store
- protection of organs (waxy cuticle, fat)
- cell membranes (phospholipid bilayer)
- steroid hormones (eg testosterone)
- source of water (respiration)
why do camels store fat in their humps
- lipids can be broken down in aerobic respiration to release energy
- creating water