Question 1
Question
Define Protein Folding
Answer
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The process by which a protein obtains its natural 3D state
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The process by which a polypeptide chain is created from mRNA
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The process by which DNA sequences are converted into an mRNA chain
Question 2
Question
Which structure of a protein shows biological activity?
Answer
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Primary
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Secondary
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Tertiary
Question 3
Question
Which of the following occurs to ALL proteins?
Answer
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Non-covalent folding
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Covalent folding
Question 4
Question
Which of the following are covalent modifications of the polypeptide chain?
Answer
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Glycosylation
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Phosphorylation
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Formation of disulphide bonds
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Van Der Waals interactions
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Electrostatic interactions
Question 5
Question
Folding corresponds to a hierarchy of protein structure
Question 6
Question
Put the following in Order
A -Unfolded
B - Nucleation
C - Secondary Structure
D - Domain
E - Active Oligomer
F - Inactive Oligomer
G - Supersecondary Structure
H - Folded Monomer
Answer
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A-B-C-G-D-H-F-E
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A-B-E-F-G-D-C-H
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A-D-C-B-E-F-H
Question 7
Question
What is meant by the 'Thermodynamic Hypothesis of Protein Folding'
Answer
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That proteins fold into different structures based on the energy available to them in the medium
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That the information for correct protein folding is found within the sequence itself
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That the protein will always fold into the lowest possible energy state
Question 8
Question
The Kinetic Hypothysis suggests that there is a specific folding pathway for each protein- protein folding is not random
Question 9
Question
Describe the features of the RNAase Refolding experiment?
Answer
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RNAase is denatured with urea
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RNAase is denatured with detergent
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And an oxidising agent to remove the disulphide bridges
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And a reducing agent to remove the disulphide bridges
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Once the denaturing agents were removed and it was re-oxdised
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Once the denaturing agents were removed and it was re-reduced
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Protein fully reformed itself and worked
Question 10
Question
How do we know the RNAase really was denatured during the experiment?
Answer
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If the protein was allowed to reform before the reducing agents were removed, the sequence showed non native sulphides and didn't work
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We don't know- we can never really KNOW anything
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If the protein was allowed to reform before the reducing agents were removed, the sequence didn't work
Question 11
Question
Which of the following are conditions for In Vitro Refolding (Like in the RNAase experiment)?
Answer
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Structure must be amenable to environmental changes
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Free energy path must be relatively smooth
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Must contain covalent bonds
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Must have slow transitions
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Structure must have unique free energy
Question 12
Question
What type of amino acid is being shown ere?
Question 13
Question
Trans formations are less stable due to their steric hindrance
Question 14
Question
Proline is added to an amino acid chain exclusively in what form?
Question 15
Question
Which of the following proteins converts cis isomers to their trans form?
Answer
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Peptidyl Propyl Isomerases
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Peptidyl Glucyl Isomerases
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Peptidyl Lipyl Isomerases
Question 16
Question
In the Cis form, the clash of functional groups around the alpha carbon is much greater due to steric hindrance
Question 17
Question
What type of bond is being shown here?
Answer
-
Disulphide
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Van Der Waals
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Electrostatic Attraction
Question 18
Question
The previous amino acid to proline experiences steric hindrance in either proline conformation
Question 19
Question
Cis proline has _ energy than/to trans proline
Question 20
Question
The two cystine molecules that bind together are known as what?
Answer
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Cysteine
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Bi-cystine
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Bi-sulphur cystine
Question 21
Question
Proteins with di-sulphide bonds are most likely to be found where?
Question 22
Question
Phosphorylation occurs on which residues?
Answer
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Serine
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Valine
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Threonine
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Tyrosine
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Glutamine
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Asparagine
Question 23
Question
Pro-sequences are found at the C-terminus
Question 24
Question
The Pro-sequence is also known as
Answer
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A chaperone sequence
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A ligation sequence
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A glycosylation sequence
Question 25
Question
Which proteins will have a pro-sequence?
Answer
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Chaperones
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Proteases
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Ligand-binding proteins
Question 26
Question
The protein with a pro-sequence will auto-cleave it before folding correctly
Question 27
Question
What is co-operativity in protein folding?
Answer
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Where one area of the protein that has already folded provides a nucleation site for another domain to fold
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The pre-formed proteins will be used as a template to fold more of that species
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Where chaperone proteins assist in protein folding
Question 28
Question
What does the Hydrophobic Zipper Model suggest?
Answer
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That hydrophobic amino acids in close proximity are more likely to interact
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That hydrophillic amino acids in close proximity are more likely to interact
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Constraining the chain and making other residues more likely to interact, which further constrains the chain, etc.