Amino acids and Proteins

Question 1

What are the essential and nonessential amino acids?

Answer 1

1) LLTTVIPMH
2) 4A,3G,CPST

Question 2

Lysine, Tryptophan, Asparagine, Aspartate, Glutamate, Glutamine letters?

Answer 2

K, W, N, D, E Q

Question 3

Selenocysteine is needed for the functioning of what 2 enzymes?

Answer 3

Glutathione peroxidase, Thioredoxin reductase

Question 4

Proline has a … amine as opposed to the other amino acids that all have a … amine?

Answer 4

secondary, primary

Question 5

All amino acids are chiral except…
Amino acids by convention are in the … form(L or D)

Answer 5

Glycine
L

Question 6

Non-polar A.A. include

Answer 6

Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine
(GAVLIM)
Proline is an exception.
VIL= BCAA

Question 7

Polar neutral A.A. include…

Answer 7

Asparagine, Glutamine, Serine, Threonine, Cysteine.
(AGCST)

Question 8

Function?
1) Hydroxyproline, Hydroxylysine
2) Y-carboxy glutamate
3) Citrulline, Ornithine
4) B-alanine
5) GABA
6) Gaba pentin
7) Penicillamine

Answer 8

1) In collagen and myosin
2) In prothrombin
3) Urea cycle
4) intermediate of coA
5) Neurotransmitter from glu
6) epilepsy treatment
7) Wilson disease treatment(chelates copper)

Question 9

If pH > pI, protein will have a net … charge.
If pH < pI, protein will have a net … charge.

Answer 9

-ve, +ve

Question 10

Pka’s to memorize(0 if pH lower than acid or higher than base)
1) Asp + Glu
2) Cys
3) Tyr
4) His
5) Lys
6) Arg
7) N and C

Answer 10

1) around 4
2) 8
3) 10
4) 6 ~ 7
5) 9.5-10
6) 12
7) 9 and 2

Question 11

Types of bonds involved in:
1) Secondary
2) Tertiary
3) Quaternary

Answer 11

1) Peptide
2) R group hydrophobic, salt bridges, and mainly disulfide bonds(covalent)
3) Non-covalent and rare disulfide

Question 12

Most destructive A.A is…

Answer 12

Proline(it has no H-bonds)

Question 13

Keratin is unique since it

Answer 13

Flips between alpha helix and B-sheet(dry hair vs heated)

Question 14

6 bonds keep iron in the middle of heme…

Answer 14

1) 4 N from tetrapyrrole rings
2) Fe-His at F8(proximal His)
3) Fe-His at E7(Distal His = makes it hard for O2 to bind initially and prevents Fe2+ > Fe 3+)

Question 15

3 factors influence O2 unloading

Answer 15

1) decrease in pH(more acid)
2) Increase CO2
3) 2,3-bisphosphoglycerate

Question 16

Lung > Tissue

Answer 16

1) Deoxy hemo in lungs becomes oxy due to high O2 pressure
2) Oxy hemo releases H+ to make carbonic acid
3) Oxy hemo goes to tissues(carbonic acid breakdown) where pH is low and unloading occurs
4) becomes Deoxy again binds CO2 and exhale
5) Repeat

Question 17

… is an endopeptidase that cleaves C terminus of aromatic A.A.

Answer 17

Chymotrypsin

Question 18

1) Marfan syndrome
2) Ehlers-Danlos

Answer 18

1) Defect in fibrillin
2) Improper triple helix of collagen(Vit C deficiency)

Question 19

Urea and guanidino residues, when added to a protein, destroy…

Answer 19

Secondary and tertiary structures

Question 20

1) Sodium deoxycholate
2) SDS

Answer 20

1) lipid emulsifier
2) Unfold polypeptide chain

Question 21

What destroys disulfide bonds?

Answer 21

Detergents and reducing agents

Question 22

1) HSP 70
2) HSP 60

Answer 22

1) Guide for protein final destination
2) Isolation chamber for proper protein folding.
Both use ATP

Question 23

1) Prolyl cis-trans isomerase
2) Protein disulfide isomerase

Answer 23

1) trans peptide bond > cis peptide bond
2) reshuffle/modify disulfide bonds(reduced) or create new ones(oxidized)

Question 24

T/F: B-sheets are more toxic than alpha helices.

Answer 24

True

Question 25

Patients with HbS maintain a low level of activity so that…

Answer 25

Deoxy HbS doesn’t increase in concentration and polymerize