Amino Acids Flashcards
What are the 6 functions of proteins?
What is the polarity difference between intracellular non-membrane bound proteins & lipid bilayer proteins?
What is the difference between an L amino acid & D amino acid? what form do amino acids take?
Defence, communication, enzymes, transport, storage, structurer
Intracellular = polar outer layer & non-polar core Lipid = non-polar outer layer & polar core (hydrophobic tails)
L: NH3 is on left hand side
D: NH3 is on right hand side
L configuration
What are the 3 letter & 1 letter code for:
Alanine
Arginine
Asparagine
Aspartic acid?
Ala, A
Arg, R
Asn, N
Asp, D
What are the 3 letter & 1 letter code for:
Cysteine Glutamate/glutamic acid Glutamine Glycine Histidine?
Cys, C Glu, E Gln, Q Gly, G His, H
What are the 3 letter & 1 letter code for:
Isoleucine Selenocysteine Leucine Lysine Methionine?
Ile, I
Sec, U
Leu, L
Met, M
What are the 3 letter & 1 letter code for:
Phenylalanine Proline Serine Threonine Tryptophan?
Phe, F Pro, P Ser, S Thr, T Trp, W
What are the 3 letter & 1 letter code for:
Tyrosine
Valine
Pyrrolysine?
Tyr, Y
Val, V
Pyl, O
Which 6 amino acids have non-polar aliphatic side chains?
Which 3 amino acids have non-polar aromatic side chains?
Glycine Alanine Valine Isoleucine Leucine Methionine
Phenylalanine
Tyrosine
Tryptophan
Which 4 amino acids have polar but uncharged side chains?
Which 5 amino acids have polar & charged side chains? what is their charge?
What are the 2 special amino acids with side chains?
Serine
Threonine
Asparagine
Glutamine
Aspartic acid - Glutamic acid - Histidine + Lysine + Arginine +
Proline, cysteine
In the forward reaction of forming a disulphide bridge:
what are the reactants?
what kind of reaction is it?
what is the product?
what is the reverse reaction?
2 cysteine
oxidation
cystine (SS), 2H+ and 2e-
reduction involving 2e- and 2H+
What is the hydrophobic effect & protein folding for:
soluble proteins? (in aqueous environment)
what is an integral protein?
what is a peripheral membrane protein?
Folds so hydrophilic (polar) side chains (both charged & uncharged) exposed to aq environment & hydrophobic/non-polar side chains backed inside
hydrophobic surface packed inside membrane & hydrophilic surface on the outside of membrane (exposed to aq environment)
protein where segments are buried (e.g membrane proteins)
proteins that only interact with hydrophilic heads in the membrane- due to polar amino acid side chains
what are post-translation modifications of amino acid side chains for?
what is the chemistry behind & what are the amino acids involved:
phosphorylation
N-glycosylation
O-glycosylation
Hydroxylation
Carboxylation
Methylation
Disulphide bond formation
function regulation of proteins
phosphate added to R group: S, T, Y
R-NH-sugar, N
R-O-sugar, S, T
OH added to R group: P, K
carboxyl added to R group: E
methyl added to R group: K, E
oxidation: C
What does it mean when:
pH = pKa
pH = pKa - 1
pH = pKa + 1
What happens to the charge of alanine at low pH, 7.4, high pH?
What is the isoelectric point?
What is on the x and y of a titration curve?
[A-] = [HA]
[A-] = 0.1[HA]
[A-] = 10[HA]
low pH = charge of +1 NH3+ and COOH cation
7.4 = charge 0 zwitterion NH3+ and COO- (loses 1H+)
high pH = charge -1 NH2 & COO- (lost 2H+ total)
pH when the amino acid is a zwitterion (charge 0)
x = equivalent OH- (where 1 is zwitterion, 0 is cation & 2 is anion) y = pH
