Amino Acid and Protein Properties

Question 1

All amino acids have…

Answer 1

Carboxylic acid group (acidic) and amine group (basic)

Question 2

Class: Basic AAs

Answer 2

NH3+ (–> NH2)

Question 3

Class: Acidic AAs

Answer 3

COOH (–>COO-)

Question 4

Class: Alcohol AAs

Answer 4

C-OH

Question 5

Class: Aromatic AAs

Answer 5

aromatic side group

Question 6

Class: Aliphatic AAs

Answer 6

hydrocarbon

Question 7

Class: Amides AAs

Answer 7

O=C-NH2

Question 8

Class: Sulfur-containing AAs

Answer 8

C-SH or C-S-C

Question 9

Which classes of AAs exhibit van der waals interactions?

Answer 9

Aromatic, Aliphatic, and Methionine (C-S-C)

Question 10

Which classes of AAs exhibit ionic bonds?

Answer 10

Acidic and Basic

Question 11

Which classes of AAs exhibit H-bonding?

Answer 11

Alcohols and Amides (C-NH2)

Question 12

Which classes of AAs exhibit dipole-dipole bonds?

Answer 12

Alcohols and Amides (C=O)

Question 13

Which classes of AAs exhibit disulfide bridges?

Answer 13

Cysteine (C-SH)

Question 14

Which classes of AAs are hydrophobic?

Answer 14

aliphatic, aromatic, sulfur-containing

Question 15

Which of the classes of AAs are hydrophilic?

Answer 15

basic, acidic, alcohols, amides

Question 16

In a titration curve, where is the pKa?

Answer 16

half way point to the equivalence point

Question 17

What is the equivalence point in a titration?

Answer 17

The point where the moles of acid and base are equal

Question 18

Which 2 AAs are good buffers at physiological pH?

Answer 18

Cysteine and Histidine

Question 19

_____ are good at buffering acids

Answer 19

acids/molecules with pKas below pH

Question 20

_____ are good at buffering bases

Answer 20

bases/molecules with pKas above pH

Question 21

Isoelectric point

Answer 21

pH at which a molecule has an equal number of positive and negative charges

Question 22

Zwitterion

Answer 22

half charged, half neutral groups