MB&B : Proteins

Question 1

What’s the central carbon in an amino acid called

Answer 1

Alpha carbon

Question 2

At what pH do amino acids exist as zwitterions

Answer 2

7.4

Question 3

What’s the only non chiral amino acid

Answer 3

Glycine

Question 4

What enantiomers of amino acids are proteins

Answer 4

L-amino acids

Question 5

Why does the enantiomers of an amino acid matter

Answer 5

Biochemical reactions and enzymes are stereospecific

Question 6

You differentiate protein enantiomers using the corn rule how

Answer 6

L isomers corn is clockwise around the a-carbon
D isomers are anticlockwise

Question 7

What are the aromatic amino acids with hydrophobic side chains

Answer 7

Phenylalanine
Tyrosine
Tryptophan

Question 8

What are the non aromatic amino acids with hydrophobic side chains

Answer 8

Glycine
Alanine
Proline
Valine
Leucine
Isoleucine
Methionine

Question 9

Amino acids with polar side chains

Answer 9

Serine
Threonine
Cysteine
asparagine
Glutamine

Question 10

Positively charged / basic amino acids +1

Answer 10

Lysine
Arginine
Histidine

Question 11

Negatively charged / acidic amino acids

Answer 11

Aspartate
Glutamate

Question 12

PKa of ionisable groups in proteins

Answer 12

Henderson-hasselbalch equation
pH= pKa + log10([A-]/[HA])

Question 13

What’s the isoelectric point

Answer 13

The pH which an ionisable molecule carries no netcharge

Question 14

What’s different about peptide bonds to other bonds

Answer 14

Partial double bond character
Intermediate c - n distance

Question 15

What is the Ramachandran plot

Answer 15

Tool to test the quality of protein structural data

Question 16

How are disulfide bonds formed

Answer 16

Inter and intramolecular covalent bonding between cysteine residues

Question 17

What are protein cofactors

Answer 17

Small organic molecules or metals and if they’re perminantly associated then it’s called a prosthetic group

Question 18

What are post translational modifications

Answer 18

They are changes that can be made to a molecule after translation
Glycosylation
Hydroxylation
Phosphorylation
Acetylation
Methylation
Ubiquitination
SUMOylation

Question 19

Glycolation

Answer 19

Adds sugar to protein
O linked in serine and threonine
N linked in asparagine

Question 20

Hydroxylation

Answer 20

The addition of a hydroxyl group

Question 21

Phosphylation

Answer 21

The addition of a phosphate group usually using atp

Question 22

Acetylation

Answer 22

The addition of acyl group

Question 23

Methylation

Answer 23

The addition of methyl groups
In lysine and arginine