R groups (side chains)

Question 1

What amino acids have R groups that are nonpolar aliphatic groups

Answer 1

1. Alanine
2. Valine
3. Leucine
4. Isoleucine
5. Glycine
6. Methionine
7. Proline

Question 2

The side chains that are nonpolar aliphatic R groups like to do what?

Answer 2

Like to cluster together with proteins & stabilize proteins structure through the hydrophobic effect

Question 3

________ has the simplest form & doesn’t contribute to interactions driven by the hydrophobic effect

Answer 3

Glycine

Question 4

Methionine

Answer 4

One of the two sulfur-containing amino acids has slightly nonpolar thioether groups in its side chain

Question 5

Proline

Answer 5

Has an aliphatic side chain (R group) with a distinctive cyclic structure

Question 6

What amino acids have aromatic R groups as their side chain?

Answer 6

1. Phenylalanine
2. Tyrosine
3. Trytophan

Question 7

________ & _________ can absorb UV light

Answer 7

Tryptophan, tyrosine (& phenylalanie)

Question 8

What amino acids have polar uncharged R groups?

Answer 8

1. Serine
2. Threonine
3. Cystenine
4. Asparagine
5. Glutamine

Question 9

Amino acids that have polar uncharged R groups are more _______ in water

Answer 9

Soluble (hydrophillic)

Question 10

The polarity of ________ & _______ is contributed by their hydroxyl group

Answer 10

Serine, Threonine

Question 12

The polarity of __________ & __________ is contributed by their amide groups

Answer 12

Asparagine & glutamine

Question 13

_______ polarity is contributed by its sulfhydryl group

Answer 13

Cysteine

Question 14

Cysteine is oxidized to form covalently linked dimeric amino acids called _________ where two cystine molecules are joined by a disulfide bond

Answer 14

Cystine

Question 15

The most hydrophilic R groups are those that are either __________ or ________ charged

Answer 15

Positively charged or negatively

Question 16

What amino acids have a positive chare at pH=7?

Answer 16

1. Lysine
2. Arginine
3. Histidine

Question 17

What amino acids have negative charged R groups?

Answer 17

1. Aspartate
2. Glutamate

Question 18

Aspartate & glutamate both have 2nd __________ group

Answer 18

Carboxyl

Question 19

Nonpolar (alphatic & aromatic) R groups are what?

Answer 19

Hydrophobic and bury away from water

Question 20

Polar uncharged R groups are what?

Answer 20

Hydrogen bonds acceptors & donors, and interact with water

Question 21

Polar charged R groups are what?

Answer 21

Cationic and anionic groups at pH = 7

Question 22

Glycine is considered ________ because of its hydrogen side group

Answer 22

Nonpolar

Question 23

Both

Question 24

Polar side chain (Polar R groups) are both hydrogen acceptor & donors & are often found at the ________ of proteins to interact with water & polar groups ( have hydroxyl & amide as their side chain)

Answer 24

Surface

Question 25

Hydroxyl make a strong ______ when ionidize

Answer 25

Nucleophile

Question 26

What amino acid within the polar uncharged R groups has hydroxyl as their R group?

Answer 26

1. Serine
2. Threonine
3. Tyrosine

Question 27

What amino acid within the polar uncharged R groups has amide as their R group?

Answer 27

1. Glutamine (amide is not basic)
2. Asparagine

Question 28

Cystenine is a strong nucleophile when deprotonated & its side chains can be cross-linked if oxidized to form a __________ that stabilize the 3D structure of proteins

Answer 28

Disulfide bridge

Question 29

Histidine

Answer 29

1. Has an aromatic ring
2. Acid or base near pH= 7.4 (common proton donor/acceptor inenzyme active)
3. Signfanct fraction protonated (+) charge at pH=7.4

Question 30

Lysine

Answer 30

1. Has an alkylamino group (NH3+)
   Has a long flexibile chain

Question 31

Arginine

Answer 31

1. Has a guanidino group (highly basic)
2. Charge stbalizied by resonance
3. Has a long flexible side chain

Question 32

_________ & _______ side chains are nitrogenous bases with positive charge at pH = 7

Answer 32

Lysine, Arginine

Question 33

Charged R gorup have ________ side chain (-)

Answer 33

Acidic

Question 34

Aspartate & Glutamate

Answer 34

1. Both dicarboxylic acids with ionized form stabilized at pH=7 (both have 2 carboxyl groups)
2. Full negative charge at pH= 7
3. Form ionic bonds with basic an=mino acids & other charged groups
4. Are hydrogen acceptors & donors
5. Can act as a base to affect ionization s