Which type of protein is conjugated?
One that contains only amino acid residues
One that contains prosthetic groups
One that is bound to a membrane
Which of the following means a protein with two identical subunits?
Which of the following proteins types tend to have various roles, as opposed to a single, defined one?
Which of the following tend not to be water soluble?
What secondary structures tend to make up fibrous proteins?
What is specific about the membrane spanning part of membrane proteins?
They are hydrophobic
They are hydrophillic
Define 'Domain' in reference to protein structure
Independent folding units of the tertiary structure that have independent functions
Independent folding units of tertiary structure that have related functions
Dependent folding units of secondary structure that have relation functions
Dependent folding units of tertiary structure that have related functions
Independent structures in a quaternary structure
Independent structures in a tertiary structure
Dependent subunits in a quaternary structure
What can be the result of a single amino acid mutation in collagen?
What is Resonance (as pertaining to protein structure)?
Where bond pairs cannot be described as a single Lewis Diagram
Where two atoms in separate molecules cause each other to vibrate
Where two atoms in separate molecules are more likely to bond to each other than to another atom
Which is the psi bond?
Between the carbonyl carbon and the alpha carbon
Between the alpha carbon and the amide group
Between the alpha carbon and the R group
Which is the phi bond?
Between the alpha carbon and the carbonyl carbon
What is Steric clashing?
Where the charge of an atom prevents it from being close to another
Where the electron arrangement of an atom prevents it from being close to another
Where the size of an atom prevents it from being close to another
Why is a peptide bond planar?
It has a double bond like structure
It's electrons clash with that of the psi bond
It's electrons clash with the phi bond
How many residues per turn in an alpha helix?
How much does an alpha helix rise per aa?
Alpha helices are stabilised by hydrogen bonding with what groups?
Carbonyl oxygen 4 amino acids away
Carbonyl oxygen 6 amino acids away
Carbonyl oxygen 8 amino acids away
The stabilising effect of the hydrogen bonds makes a loop of how many atoms?
Which of the following destabilize an alpha helix?
Beta sheets rise by 3.47A per residue in anti-parallel sheets
In parallel sheets, there is a rise of .... per residue
3 residues per turn of the strand are pictured as a helix
Anti-parallel strands are _ stable than parallel ones
Side chains all point the same way (in the plane of the sheet)
What is the role of loops?
Connecting alpha and beta sheets
Connecting alpha helices and alpha helices
Connecting beta sheets and beta sheets
Loops contain mostly hydrophillic residues & are found on the protein surface
What is the role of beta turns?
To allow beta sheets to reverse direction
To connect beta sheets together
To link protein subunits together
What two amino acids cannot be contained within a beta sheet?
Beta turns link the oxygen of the carbonyl group and the hydrogen of the nitrile group 4 residues away
Levinthals Paradox- if a protein folded by trying each fold in a sequence, it would take an impossibly long time to fold correctly. Therefore, protein folding cannot be random or sequential
What is this?
The energy change as proteins fold
Gibbs free energy
Why are the internal interactions of protein folding unfavorable?
It decreases entropy
They're hydrophobic in a hydrophillic environment
They prevent the protein from folding correctly
Non-covalent and hydrophobic effects (which effects free water) decrease enthalpy
Change in energy during folding = Internal interactions - (Hydrophobic effect + conformational entropy)
Proteins fold towards configurations with the...
Easiest energy to reach (energy closest to that of unfolded protein)
What can slow the progress of protein folding?
A local low energy minimum
A local high energy minimum
What is nucleation?
Reversible secondary structure formation
Reversible tertiary structure formation
Reversible quaternary structure formation
Which of the following happens after nucleation?
The secondary structure aggregation forms a molten globular intermediate
Domains adjust to the lowest energy form
The protein is capable of conformational change after forming