Proteins

Question 1

Which form are all amino acids in ?

Answer 1

L optical isomer

Question 2

Hydrophobic

Answer 2

Glycine 
Alanine
Proline
Valine
Leucine
Isoleucine 
Tryptophan 
Phenylalanine

Question 3

Hydrophilic

Answer 3

Serine 
Theory one
Tyrosine
Asparagine
Glutamine
Cysteine

Question 4

Positively charged side chain

Answer 4

Arginine
Lysine
Histidine is protonated (+) under pH 6

Question 5

Negatively charged

Answer 5

Glutamate

Aspartate

Question 6

Why can proteins not tolerate a great change in pH?

Answer 6

Ionisation state of amino acids is essential for function.
Changes in pH = change in ionisation state = change in property
Amino acids can take up and release protons = gives them capacity to resist some changes in pH

Question 7

When do disulphide bridges form?

Answer 7

Cytosine chains oxidise

Covalent bond between 2 amino acids

Question 8

Why does proline cause a kink in the peptide chain?

Answer 8

When proline is added = loss of NH group
Side chain can’t form hydrogen bonds with C=O of another part of chain
KINK

Question 9

What is a parallel beta strand?

Answer 9

Beta sheets run parallel to each other

Beta sheets run anti parallel = antiparallel beta sheet

Question 10

How does warfarin work?

Answer 10

Glutamate needs to be converted to gamma-carboxylglutamate
This is needed for calcium binding
Warfarin inhibits this reaction