Aminosyrer

Question 1

G

Answer 1

Gly, Glycine

Simplest amino acid
Single hydrogen atom as its side chain
Achiral
Hydrophobic

Question 2

A

Answer 2

Ala, Alanine

Next simplest amino acid.
Has methyl group (-CH3) as side chain
Hydrophobic

Question 3

P

Answer 3

Pro, Proline

Aliphatic side chain, where side chain is bonded to both the nitrogen and alpha-carbon atoms, yielding a pyrrolidine ring.
Influences protein architecture.
Hydrophobic

Question 4

V

Answer 4

Val, Valine

Larger hydrocarbon side chain
Hydrophobic

Question 5

L

Answer 5

Leu, Leucine

Larger hydrocarbon side chain
Hydrophobic

Question 6

I

Answer 6

Ile, Isoleucine

Larger hydrocarbon side chain. Includes an additional chiral center
Hydrophobic

Question 7

M

Answer 7

Met, Methionine

Contains largely aliphatic side chain that includes a thioether (- S -) group.
Hydrophobic

Question 8

W

Answer 8

Trp, Tryptophan

Indole group joined to a methylene ( - CH2 -) group; comprises two fused rings containing an NH group.
Less hydrophobic bc of side chain NH group.

Question 9

F

Answer 9

Phe, Phenylalanine

Contains phenyl ring attached in place of one of the hydrogen atoms of alanine
Hydrophobic

Question 10

S

Answer 10

Ser, Serine

Contain hydroxyl group (-OH) attached to hydrophobic side chain. Makes it more hydrophilic
Polar

Question 11

T

Answer 11

Thr, Threonine

Contain hydroxyl group (-OH) attached to hydrophobic side chain. Makes it more hydrophilic.
Polar

Question 12

Y

Answer 12

Tyr, Tyrosine

Contain hydroxyl group (-OH) attached to hydrophobic side chain. Makes it more hydrophilic.
Polar

Question 13

N

Answer 13

Asn, Asparagine

Terminal carboxamide
Polar

Question 14

Q

Answer 14

Gln, Glutamine

Terminal carboxamide. Side chain one methylene longer than Asparagine.
Polar

Question 15

C

Answer 15

Cys, Cysteine

Sulfhydryl, or thiol (-SH) group in place of (-OH). Thiol group much more reactive. Pairs of sulfhydryl groups may come together to form disulfide bonds, which are particularly important in stabilizing some proteins.
Polar

Question 16

K

Answer 16

Lys, Lysine

Long side chains that terminate with groups that are positively charged at neutral pH.
Capped by a primary amino group.
Hydrophilic

Question 17

R

Answer 17

Arg, Arginine

Long side chains that terminate with groups that are positively charged at neutral pH.
Capped by a guanidinium group.
Hydrophilic.

Question 18

H

Answer 18

His, Histidine

Contains an imidazole group, an aromatic ring that can also be positively charged. With a pKa value near 6, it can be uncharged or positively charged near neutral pH, depending on local environment.
Often found in active sites of enzymes, where the ring can bind and release protons in the course of the enzymatic reaction.
Hydrophilic.

Question 19

D

Answer 19

Asp, Aspartate

Negatively charged at physiological pH.

Question 20

E

Answer 20

Glu, Glutamate

Negatively charged at physiological pH.