module 3 amino acids

what are proteins?

linear polymers of amino acids

what are the advantages of smaller simple building blocks like amino acids?

simplicity allows for rebuilding and breaking easily

recycling is easier when the components are already reusable

diversity of amino acids allows for vast number of molecules

what is a non polar amino acid?

it has no charge and no H-bonding ability. and residues often buried in the core of a protein.

what are the 7 non polar amino acids?

Glycine (Gly, G)

Alanine (Ala, A)

Valine (Val,V)

Leucine (Leu, L)

Isoleucine (Ile, I)

Proline (Pro,P)

Methionine (Met, M)

what is an aromatic amino acid?

an amino acid with a ringed side chain

what are the three aromatics?

Tyrosine (Tyr,Y)

Phenylalaline (Phe, F)

Tryptophan (Trp, W)wh

which is the largest and smallest amino acid?

tryptophan(Trp,W)-largest

glygine (gly,g)-smallest

what is post-translational modification and give and example

p=is when an amino acid is modified after it has already ben translated into its protein. this is to regulate protein structure and function. 

ex. phosphorylation, phosphates added by kinases to specific hydroxyl groups on (tyrosine, serine and threonine)

what are polar uncharged amino acids?

no charge but have the ability to form H-bonds

what are the five polar unchargede amino acids?

Cysteine (Cys,C)

Asparagine (Asn, N)

Glutamine (Gln, Q)

Serine (Ser, S)

Threonine (Thr, T)

what is special about cysteine?

it is the only amino acid that can form a disulfide bond.

what are disulfide bonds and why are they important?

forming though the oxidation of sulfhydryl groups. forms strong covalent linkages for stability.

what are polar postively charged amino acids?

carry a positive charge and have the ability to form H-bonds

what are the 3 polar pos. charged amino acids?

Lysine (Lys, K)

Arginine (Arg,R)

Histidine (His,H)

what is the function of Histidine having an Imidazole group on its side chain?

may act as a donor or acceptor in certain enzymatic rxns

which polar po. charged amino acid has a guadadino group?

Arginine (Arg, R)

what is a polar neg. charged amino acid?

has a neg. charge and has the ability to form amino acids.

what are the 2 polar n eg. charged amino acids?

Aspartate (Asp, D)

Glutamate (Glu, E)

what is a diprotic?

amino acid with two buffering regions

what do ALL amino acids have?

alpha-carbon, carboxyl group (on the c terminus)and amino group ( on the N-terminus). and at least teo groups that accept or donate protons.

what side chain groups are ionizable?

1) carboxyl

2)amino group

3) side chains of all triprotic amino acids

when pH is below the pKa, which state dominates?

the protonated state

when pH is above the pKa which state dominates?

the unprotonated state.

what are the pKa’s of carboxyl and amino groups?

carboxyl(2.0)

amino(10.0)

what is the isoelectric point on a titration curve?

is the average of the pKa’s on either side of where the net charge is zero.

what are the four different types of titration curve trends?

1) diprotic

2) acidic

3) basics

4) Histidine

all amino acids will fall into 1 of these.