Frage 1
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Alpha helices are a helix-helix structure
Frage 2
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Which of the following best describes an alpha helix?
Frage 3
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Helix-helix packing can be shown by highlighting every _ residues?
Frage 4
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Alpha helices must follow particular rules when packing together
Frage 5
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Describe the ridges of the following proteins
Frage 6
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The angle between two packed helices depends on which type of ridges pack into which troughs.
Frage 7
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The troughs of one alpha helix will be filled by the 'backbone' of another
Frage 8
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Beta sheets twist slightly _ each other
Frage 9
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The angle between two beta sheets is approx....?
Antworten
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30 degrees
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60 degrees
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90 degrees
Frage 10
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Where in the plane is each color (ignore green)
Antworten
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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
Frage 11
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The strands of beta sheets are held together by backbone hydrogen bonding
Frage 12
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The angle between sheets is determined by their...
Antworten
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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
Frage 13
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How are the aa side chains arranged in beta sheets?
Antworten
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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
Frage 14
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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?
Frage 15
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Name three things that can be used in protein folding to encourage correct folding?
Antworten
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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
Frage 16
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Negative Free Energy is less favorable
Frage 17
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Concerning entropy- less order is more favorable
Frage 18
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Which of the following is the equation for the free energy change of a folded protein
Antworten
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ΔG = ΔH - TΔS
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ΔH = ΔG x TΔS
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TΔS = ΔH + ΔG
Frage 19
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Hydrogen bonds are the least common type of bond in proteins
Frage 20
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What's the enthalpy change of a H bond formation?
Antworten
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-4 to -30 kJmol
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-4 to -3 kJmol
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-40 to -30 kJmol
Frage 21
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A hydrophobic core in water is entropically favorable
Frage 22
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Why is hydrophobic cores in water _favorable?
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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
Frage 23
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Why do hydrophobic proteins fold?
Antworten
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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
Frage 24
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As water ordering decreases, entropy decreases
Frage 25
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Why is energy needed to maintain the folding of a (hydrophobic) protein (i.e. from hydrogen bonds etc.)?
Antworten
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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
Frage 26
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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
Frage 27
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In protein folding, ΔH is negative, and -TΔS is positive