what are the properties of living things?
- complicated + highly organised
- structure serves a purpose
- transforms energy to drive reactions
- self replication
what is the organisational level of biochemicals
- inorganic precursor (CO2, H2O)
- metabolites (pyruvate)
- building blocks (amino acids)
- macromolecules (proteins, lipids)
- supramolecular (ribosomes)
- organelles (nucleus, mitochondria)
- cell
types of bonds
** refer to the image from lectures to identify bonds in image
strong (covalent) vs weak (van der waals, hydrogen- strongest, ionic interactions, hydrophobic interactions)
describe hydrophobic interactions
tendency of non-polar molecules, fold up into a ball in water because has hydrophobic parts
function of weak bonds
- maintain biological structure
- determine biomolecular interactions
- movement
- mediate biomolecular recognition
define biomolecular recognition
due to weak chemical forces
is the environmental limits in which biological systems can function in
bacterial vs animal vs plant cells
bacterial- has flagella (no nuclear membrane)
bacterial + animal- no plastids (give plants colour)
animal- membrane bound organelles
animal + plant- has nuclear membrane
plant- has chloroplast
plant + bacterial- has cell wall
membrane functions + how much % of genes encoded in it
- boundary
- exclude toxins + ions
- transport
- interaction with other cells
- surface for biological reactions to occur
30%
structure of membrane
5nm thick lipid bilayer
contains lipids- provide structure, 500-1000 different types, are amphipathic- has both hydrophobic + hydrophilic parts
also contains proteins- functionary, 3 different types- integral, peripheral and lipid anchored
describe micelles
lipids
detergents + soap form micelles- self limiting structures, ball with tails facing inside
describe movement of lipids/proteins in mosaic model
lateral, rotationally, flipflop- rare
describe membrane phase transitions
depends on transition temp., which is determined by lipid composition of membrane
below transition temp. = tightly packed, gel
above transition temp. = mobile + flexible, liquid crystals
4 classes of lipids
- glycerophospholipids
- spingolipids
- cholesterol
- glycolipids
describe glycerophospholipids
- essential
-3 major types found in mammals
- phosphatidylethanolamine
- phosphatidylserine
- phosphatidylcholine
describe sphingolipids
- important for muscle + nerve membranes
-invovled in cell signalling + signal transduction
-if join a fatty acid to it with a amide bond- makes a ceramide
-but most common form is sphingomyelin
describe cholesterol
-vital
-maintains cell structure + fluidity
-at high temp. = low fluidity
-at low temp. = high fluidity
describe glycolipids
are basically glycerophospholipids, but with carbohydrates attached
define lipid rafts
- localised raised regions of sphingolipids + cholesterol
-insoluble in non-ionic detergents
-invovled in cell signalling + signal transduction
-contains 2x amount of cholesterol + 30% of sphingolipids in rest of membrane
