Pregunta 1
Pregunta
Alpha helices are a helix-helix structure
Pregunta 2
Pregunta
Which of the following best describes an alpha helix?
Pregunta 3
Pregunta
Helix-helix packing can be shown by highlighting every _ residues?
Pregunta 4
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Alpha helices must follow particular rules when packing together
Pregunta 5
Pregunta
Describe the ridges of the following proteins
Pregunta 6
Pregunta
The angle between two packed helices depends on which type of ridges pack into which troughs.
Pregunta 7
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The troughs of one alpha helix will be filled by the 'backbone' of another
Pregunta 8
Pregunta
Beta sheets twist slightly _ each other
Pregunta 9
Pregunta
The angle between two beta sheets is approx....?
Respuesta
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30 degrees
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60 degrees
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90 degrees
Pregunta 10
Pregunta
Where in the plane is each color (ignore green)
Respuesta
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Yellow- above plane
White- below plane
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White- above plane
Yellow- below plane
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The amino acids will point in opposite directions
Pregunta 11
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The strands of beta sheets are held together by backbone hydrogen bonding
Pregunta 12
Pregunta
The angle between sheets is determined by their...
Respuesta
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Right handed twist
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Left handed twist
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Length
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Amino acid side chains
Pregunta 13
Pregunta
How are the aa side chains arranged in beta sheets?
Respuesta
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The amino acid residue side chains of one beta sheet pack between the spaces between side chains on the adjacent beta sheet
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The amino acids on one beta sheet will have no residue where the other beta sheet has one (they're removed)
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The amino acids with residues attached will alternate between beta sheets
Pregunta 14
Pregunta
When an alpha helix and a beta sheet pack together, the groove the beta sheet lies in tends to be made by amino acids how far apart?
Pregunta 15
Pregunta
Name three things that can be used in protein folding to encourage correct folding?
Respuesta
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Non-native interactions (as long as they are reversible)
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Pinching (isolates subdomains for folding)
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The removal of a domain for folding, before it's re-addition
Pregunta 16
Pregunta
Negative Free Energy is less favorable
Pregunta 17
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Concerning entropy- less order is more favorable
Pregunta 18
Pregunta
Which of the following is the equation for the free energy change of a folded protein
Respuesta
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ΔG = ΔH - TΔS
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ΔH = ΔG x TΔS
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TΔS = ΔH + ΔG
Pregunta 19
Pregunta
Hydrogen bonds are the least common type of bond in proteins
Pregunta 20
Pregunta
What's the enthalpy change of a H bond formation?
Respuesta
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-4 to -30 kJmol
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-4 to -3 kJmol
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-40 to -30 kJmol
Pregunta 21
Pregunta
A hydrophobic core in water is entropically favorable
Pregunta 22
Pregunta
Why is hydrophobic cores in water _favorable?
Respuesta
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They make the water molecules more ordered, decreasing entropy
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They make the water molecules less ordered, increasing entropy
Pregunta 23
Pregunta
Why do hydrophobic proteins fold?
Respuesta
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Folded proteins have a reduced surface area, leading to a reduced number of organised water molecules, leading to a lower decrease of entropy
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Folded proteins have a reduced surface area, leading to a reduced number of organised water molecules, leading to a lower increase of entropy
Pregunta 24
Pregunta
As water ordering decreases, entropy decreases
Pregunta 25
Pregunta
Why is energy needed to maintain the folding of a (hydrophobic) protein (i.e. from hydrogen bonds etc.)?
Respuesta
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Because the unfolded state of the protein is more entropically favorable than the folded state
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Because though the folded protein is more entropically favorable, it's folding decreases entropy, which is unfavorable
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So energy must be produced to maintain the fold
Pregunta 26
Pregunta
Heating denatures a protein because it breaks the bonds required to offset the negative change in entropy caused by the protein folding i.e, it makes ΔH less negative
Pregunta 27
Pregunta
In protein folding, ΔH is negative, and -TΔS is positive