Biochemistry: Amino Acids, Proteins, Water and pH Flashcards
(38 cards)
what shape is water
tetrahedral
hydrophilic
dissolves in water
how do hydrophilic molecules dissolve in hydrophilic substances
electrostatic interactions - ion-dipole, dipole-dipole interactions
hydrogen bond
covalent bond between a hydrogen atom and a more electronegative one creating a polarised bond
what is the strength of a hydrogen bond compared to covalent
- individually weaker
- collectively strong
hydrophobic
non-polar substances are insoluble in water
what is the hydrophobic effect
2 layers form when polar and non-polar substances are mixed
ampipathic
molecules with both hydrophilic and hydrophobic parts
describe an ampipathic molecule
polar ‘head’, hydrophobic ‘tail’
what do ampipathic molecules form in water
micelles
what if the function of the proteins in the phospholipid bilayer
- confer selectivity
- involved inrecognition
what are amino acids made of
proteins and polypeptides
in an amino acid what is bonded to the central carbon atom
- amide group
- R group
- carboxyl group
- hydrogen
steroisomer
non-superimposable mirror images
what are the 4 types of amino acids
- polar (uncharged)
- non-polar (uncharged)
- acidic
- basic
describe peptide bond formation
- the carboxyl and amino group of 2 amino acids bond via peptidyl transferase
- this forms an amide group
what direction does peptide bond formation occur in
towards the C terminal
what is a peptide bond
partial double bond character electrons, form the N and C terminal but arent covanlently bonded
describe peptide bonds
planar, strong and rigid
acid
substance that donates a proton
base
proton acceptor
what does the strength of an acid depend on
how readily it donates a proton
what equation is used to measure an acids strength
dissociation constant
Ka= [H+][A-]/[HA]
what is pH a measurement of
the amount of protons in a solution
