Amino Acid Structures

Question 1

Arginine

Answer 1

Positively Charged

Arg, R

Capped with guanidinium group

Question 2

Asparagine

Answer 2

Polar derivative fo Aspartate

Asn, N

Contains terminal carboxamide in place of carboxyic acid

Question 3

Aspartate

Answer 3

Negatively charged

Asp, D

Same as aspartic acid

Question 4

Cysteine

Answer 4

Polar, forms disulfide bonds

Cys, C

Similar to serine but has sulfhydryl (SH) group in place of hydroxyl -> much more reactive

Question 5

Glutamate

Answer 5

Negatively charged

Glu, E

Same as glutamic acid

Question 6

Glutamine

Answer 6

Polar derivative of Glutamate

Gln, Q

Contains terminal carboxamide in place of carboxylic acid

Side chain is one methylene group longer than asparagine

Question 7

Glycine

Answer 7

Hydrophobic small

Gly, G

achiral

Question 8

Histidine

Answer 8

Postively charged imidazole group (aromatic ring)

Can be uncharged or charged near neutral pH -> often at enzyme active sites to bind/release H

His, H

Question 9

Isoleucine

Answer 9

Hydrophobic larger

Ile, I

Question 10

Leucine

Answer 10

Hydrophobic larger

Leu, L

Question 11

Lysine

Answer 11

Postively charged

Lys, K

Capped with primary amino group

Question 12

Methionine

Answer 12

Hydrophobic larger

Has sulfur (thioether group)

Met, M

Question 13

Phenylalanine

Answer 13

(Purely) Hydrophobic, aromatic side chain

Phe, F

Question 14

Proline

Answer 14

Hydrophobic

Closed Ring

Pro, P

Question 15

Serine

Answer 15

Polar, Hydrophilic

Ser, S

Like Alanine with OH

Question 16

Threonine

Answer 16

Polar, Hydrophilic

Thr, T

Like Valine with OH in place of methyl group

Question 17

Tryptophan

Answer 17

Hydrophobic (less than phenylalanine because of NH groups), aromatic side chain

Trp, W

Question 18

Valine

Answer 18

Question 19

Tyrosine

Answer 19

Hydrophilic, aromatic

Tyr, Y

Like phenylalanine with OH replacing H on aromtic ring

Question 20

Alanine

Answer 20

Hydrophobic small

Ala, A