AMINO ACIDS

Glycine, Gly, G

Alanine, Ala, A

Valine, Val, V

Leucine, Leu, L

Methionine, Met, M

Isoleucine, Ile, I

Serine, Ser, S

Threonine, Thr, T

Cysteine, Cys, C

Proline, Pro, P

Asparagine. Asn, N

Glutamine, Gln, Q

Lysine, Lys, K

Arginine. Arg, R

Histidine, His, H

Aspartate, Asp, D

Glutamate, Glu, E

Phenylalanine, Phe, F

Tyrosine. Tyr, Y

Tryptophan, Trp, W

Proteins

are polymers that are assembled from amino acid monomers that have been linked together.

amino group and a carboxylic acid group.

Each amino acid contains an

peptide bonds

Amino acids are coupled together by amide linkages, also called

polypeptides, proteins.

Chains comprised of fewer than 40 or 50 amino acids are often called while still larger chains are called

L-amino acids

Naturally occurring amino acids are

L- amino acid

The amino acid is an ______  if the amino group is on the left.

D- amino acids

______have the amino group placed on the right.

Hydrophobic amino acids

Have nonpolar side chains that interact very weakly with water

Hydrophobic amino acids

Most have aliphatic chains

Hydrophobic amino acids

Almost always located in the interior of a protein molecule where they can avoid interactions with water

Polar amino acids

Contain H-bonding groups and thus, can interact with water 

Polar amino acids

Can be found on the waterexposed surface of proteins

Charged amino acids

Side chains are virtually always charged under physiological conditions

Charged amino acids

Located on the protein's surface

The Henderson-Hasselbalch equation

gives the relationship between the pKa of an acid and the pH of the solution. It also says whether an acid, based on its pKa , will be protonated or deprotonated at a certain pH value.

Deprotonated

when placed in a solution whose pH is higher than the acid’s pKa

❑ Protonated

when placed in a solution whose pH is lower than the acid’s pKa

TRUE

Amino acids are weak polyprotic acids. True or False

amphoteric

Amino acids are also said to be ______because they will react with either acids or bases.

The isoelectric point (pI) of a molecule

is the pH at which the molecule carries no net electric charge