Amino Acids, Lecture (sept 18 2024) (L4)

Question 1

Is cystine polar or non=polar?

Answer 1

Some Sources claim it as nonpolar, but it can be argued as both

Question 2

Is methyl hydrophilic or hydrophobic?

Answer 2

phobic

Question 3

Most simple amino acid structure?

Answer 3

glycine

Question 4

R group of methionine?

Answer 4

C-C-S-C
CH2

Question 5

R group of threonine?

Answer 5

C-C
|OH
like valine but with one OH group
three things, 1 OH

Question 6

R group of tyrosine?

Answer 6

C-Phenyl +OH (group at end)
Phenylaline + an OH group

Question 7

Which is the most flexible amino acid?

Answer 7

Glycine, because it only has the R group as Hydrogen

Question 8

Is glycine hydrophobic or hydrophillic?

Answer 8

Hydrophobic

Question 9

Which is more polar? Alanine vs. serine?

Answer 9

Serine, because it has an OH group

Question 10

What makes cysteine unique?

Answer 10

It’s SH group allows for it to create disulfide bonds between other cysteine atoms
C-S-S-C

Question 11

Which amino acid is not considered an amino but an imino acid? Why?

Answer 11

Proline

Question 12

Unique characteristic about proline?

Answer 12

Very rigid, because of bond

Question 13

Bulkiest amino acid?

Answer 13

Tryptophan (has 2 rings)

Question 14

Which amino acids have aromatic side chains?

Answer 14

tyrosine, phenylalanine, tryptophan

Question 15

What makes the amino acids charged side chains?

Answer 15

pH is around 7.4

Question 16

Do peptide bonds have any rotation?

Answer 16

No

Question 17

What is a peptide bond?

Answer 17

the bond that connects 2 amino acids

Question 18

How is a polymer of an amino acid made?

Answer 18

the Carboxyl carbon of a.a#1 connects to the Nitrogen of a.a#2. H2O is a product (cuz O- group and H are lost)

Question 19

Polypeptide definition

Answer 19

any chain of
amino acids linked to one
another via peptide bonds

Question 20

Protein definition

Answer 20

usually a longer
peptide which has folded into a
unique 3D shape and with a
defined function

Question 21

length of a protein

Answer 21

100 to 1000 amino acids

Question 22

Protein vs. polypeptide?

Answer 22

Protein: 3D structure and has a defined function
Peptide:

Question 23

pKa of carboxyl in aspartic acid?

Answer 23

3.9

Question 24

pKa of carboxyl in glutamic acid?

Answer 24

4.3

Question 25

pKa of amino in lysine?

Answer 25

10.5

Question 26

What is guanidium

Answer 26

carbon bonded to 3 amine groups (one has a charge)

Question 27

Imidazole pKa?

Answer 27

6

Question 28

Tyrosine one letter code?

Answer 28

Y

Question 29

Tryptophan 1 letter code?

Answer 29

W

Question 30

General rule for 1 letter codes?

Answer 30

Smallest amino acid takes the first letter, if theres multiple a.a that start with same letter

Question 31

Threonine one letter code?

Answer 31

T

Question 32

Weirdest one letter code?

Answer 32

Glutamine: Q

Question 33

Most hydrophobic amino acid?

Answer 33

Isoleucine

Question 34

Most hydrophilic amino acid?

Answer 34

Arginine