Amino Acids

Question 1

Proteins are…

Answer 1

Linear heteropolymers of alpha amino acids.

Question 2

Proteins only contain which type of amino acids?

Answer 2

L amino acids.

Question 3

All amino acids are chiral except…

Answer 3

Glycine.

Question 4

Nonpolar, aliphatic R group side chains

Answer 4

R side chain is an alkyl group.

Question 5

Aromatic R group side chains

Answer 5

R side chain is an aromatic group.

Question 6

Polar, uncharged R group side chains

Answer 6

Can form hydrogen bonds (have an oxygen or nitrogen). Cysteine can form disulfide bonds (has a sulfur).

Question 7

Positively charged R groups

Answer 7

Long chains, contain positively charged amino groups. Histidine has N but forms a ring.

Question 8

Negatively charged R groups

Answer 8

Have a deprotonated carboxyl group.

Question 9

What are the essential amino acids?

Answer 9

Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.

Question 10

What are the conditionally non-essential amino acids?

Answer 10

Arginine, cystine, glutamine, glycine, proline, tyrosine.

Question 11

What are the non-essential amino acids?

Answer 11

Alanine, asparagine, aspartate, glutamate and serine.

Question 12

The carboxylic acid of an amino acid will be protonated at…

Answer 12

An acidic (low) pH. First to deprotonate.

Question 13

The amino group of an amino acid will be deprotonated at…

Answer 13

A basic (high) pH. Last to deprotonate.

Question 14

At a low pH, amino acids are…

Answer 14

Positively charged.

Question 15

At a high pH, amino acids are…

Answer 15

Negatively charged.

Question 16

At the isoelectric point…

Answer 16

The amino acid is least soluble in water and does not migrate in an electric field.

Question 17

Average molecule weight of an amino acid

Answer 17

110

Question 18

How many nucleotides for one amino acid?

Answer 18

3

Question 19

Glycine

Answer 19

Gly

Nonpolar

Question 20

Alanine

Answer 20

Ala

Nonpolar

Question 21

Proline

Answer 21

Pro

Nonpolar

Question 22

Valine

Answer 22

Val

Nonpolar

Question 23

Leucine

Answer 23

Leu

Nonpolar

Question 24

Isoleucine

Answer 24

Ile

Nonpolar

Question 25

Methionine

Answer 25

Met | Nonpolar

Question 26

Phenylalanine

Answer 26

Phe | Aromatic

Question 27

Tyrosine

Answer 27

Try | Aromatic

Question 28

Tryptophan

Answer 28

Trp | Aromatic

Question 29

Serine

Answer 29

Ser | Polar, uncharged

Question 30

Threonine

Answer 30

Thr | Polar, uncharged

Question 31

Cysteine

Answer 31

Cys | Polar, uncharged

Question 32

Asparagine

Answer 32

Asn | Polar, uncharged

Question 33

Glutamine

Answer 33

Gln | Polar, uncharged

Question 34

Lysine

Answer 34

Lys | Positive

Question 35

Histidine

Answer 35

His | Positive

Question 36

Arginine

Answer 36

Arg | Positive

Question 37

Aspartate

Answer 37

Asp | Negative

Question 38

Glutamate

Answer 38

Glu | Negative

Question 39

Nonpolat, aromatic and polar amino acids all have a pI around...

Answer 39

5/6

Question 40

Positively charged amino acids have a pI around...

Answer 40

9/10. This is because they have a positively charged amino group in their side chain which gets deprotonated at a high pH.

Question 41

Negatively charged amino acids have a pI around...

Answer 41

2/3. This is because they have a negatively charged side chain that is deprotonated at a low pH.