Topic 2

Question 1

structure of amino acid

Answer 1

carboxyl group
amino group
alpha-carbon center
hydrogen
variable side chain

Question 2

chirality

Answer 2

alpha-carbon bound to 4 different groups; all amino acids are chiral except glycine

Question 3

amphoteric

Answer 3

ability to react as an acid or base due to carboxyl and amino groups

Question 4

peptide bonding

Answer 4

when he carboxyl group of one molecule reacts with the amino group of another, releasing water

Question 5

stereoisomerism

Answer 5

when two molecules have the same atoms, but arranged differently spatially.

Question 6

human amino acid stereoisomerism

Answer 6

only the L-amino acids are used to make proteins

Question 7

amino acid classification

Answer 7

polar/non-polar
aromatic
+/- charged
hydrophobic/philic

Question 8

non-polar R-groups

Answer 8

glycine
alanine
proline
valine
leucine
isoleucine
methionine

Question 9

aromatic R-groups

Answer 9

phenylalanine
tyrosine
tryptophan
histidine (?)

Question 10

polar uncharged R-groups

Answer 10

serene
threonine
cysteine
asparagine
glutamine

Question 11

polar (+) R-groups

Answer 11

lysine
argentine
histidine

Question 12

polar (-) R-groups

Answer 12

aspartate

glutamate

Question 13

branched chain R-groups

Answer 13

valine
leucine
isoleucine

Question 14

acidic R-groups

Answer 14

aspartic acid/aspartate

glutamic acid/glutamate

Question 15

alkaline R-groups

Answer 15

lysine
arginine
histidine

Question 16

amide R-groups

Answer 16

asparagine

glutamine

Question 17

hydroxyl R-groups

Answer 17

serine
threonine
tyrosine

Question 18

achiral R-group

Answer 18

glycine

Question 19

hydrophilic R-groups

Answer 19

all of the polar groups

Question 20

sulfur R-groups

Answer 20

cysteine

methionine

Question 21

zwitterion

Answer 21

predominates at neutral pH

amphoteric

Question 22

isoelectric pH (pI)

Answer 22

pH at which net charge is 0

Question 23

titration of amino acids importance

Answer 23

net charge of the molecule at various ionic environments which has implication on

1. biochemical reaction characteristics at various ionic conditions that may occur at different situations arising from normal reactions
2. three dimensional spatial orientation of the molecule to interacted with another
3. development of certain diseases

Question 24

amino acid polymerization

Answer 24

condensation reaction forming a peptide bond

Question 25

protein interactions

Answer 25

functional groups of molecules can interact with amino acid side chains and produce hydrogen bonds

Question 26

modification of amino acid R-group structure

Answer 26

1. regulate biochemical functions
2. form signaling molecules
3. helps in targeting or anchoring to membrane
4. enhance protein-protein interactions

Question 27

covalent modification of amino acid structures

Answer 27

hydroxylation: pro, lys
carboxylation: glu
methylation
acetylation: lys
phosphorylation: ser, thr, tyr
carb moieties
lipid moieties

Question 28

O-glycosylation

carb moieties

Answer 28

serine
threonine
tyrosine

Question 29

N-glycosylation

carb moieties

Answer 29

asparagine

Question 30

lipid moieties

Answer 30

cysteine

glycine

Question 31

uncommon amino acid modifications

Answer 31

4-hydroxyproline
5-hydroxylysine
6-N-methyllysine
γ-carboxyglutamate
selenocysteine