Chapter 3

Question 1

Disulfide bonds

Answer 1

2 cysteine residues which can be on the same, or opposite chains
Covalent link
Stabilizing force

Question 2

Histidine can be what and why?

Answer 2

proton donor or acceptor because of its ability

to create a + charge

Question 3

If pH above pKa

Answer 3

unprotonated

Question 4

L-stereoisomers are found in what?

Answer 4

Proteins

Question 5

Zwitterions

Answer 5

Have both a positive and negative group (amino, carboxyl, R)

In neutral pH solution

Question 6

Aromatic amino acids are

Answer 6

hydrophobic

Question 7

All OH groups can what?

Answer 7

phosphorylize

Question 8

what are the pka’s of:
Carboxyl groups
Amino Groups

Answer 8

2

10

Question 9

If pH below pKa

Answer 9

protonated

Question 10

If pH > P

Answer 10

amino acid net charge is negative (more protons,

protonated)

Question 11

Isoelectronic point

Answer 11

pH where the net charge is 0

Question 12

Polar amino acids can form what?

Answer 12

hydrogen bonds

Question 13

Amino acids consist of what?

Answer 13

Alpha-carbon, Alpha-amino, Alpha-carboxyl and a side chain

Question 14

How are Amino acids joined?

Answer 14

covalently through peptide bonds

Question 15

If pH < P

Answer 15

amino acid net charge is positive (less protons, unprotonated)