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6. Which residue location is INCORRECT?

  • Charged: protein surface
  • Uncharged polar: surface/interior
  • Hydrophobic: exterior
  • Hydrophobic: interior

7. Psi (ψ) and Phi (φ) angles are important in peptide structure. What bond does the PSI bond correlate with?

  • Cα-C
  • C-N
  • Cα-N
  • C-C

8. Which isomer occurs naturally?

  • L
  • D
  • Both
  • Neither

9. What is the equation for Kw and what is it equivalent to?

  • Kw = [H+]/[OH-] = 14.00
  • Kw = [H+][OH-] = 1 x 10^14
  • Kw = [H+][OH-] = 1 x 10^-14
  • Kw = [H+][OH-] = 14.00

10. What is not a feature of amyloid structure?

  • Branched structure
  • Rich in β-sheets perpendicular to the fibril (axis)
  • Diameter of 7-10 nm
  • Aromatic residues stabilise

11. What is NOT a component of NMR?

  • Studying the chemical and physical environment of an atom
  • Crystalising and immobilising a single pure protein
  • Using magnetism to align nuclei into the magnetic field
  • Detecting 3D structures

12. How do you calculate pI?

  • You add the furthest 2 pKa values for each amino acid group
  • You add the closest 2 pKa values for each amino acid group and divide by 2
  • You add the closest 2 pKa values for each amino acid group
  • You add the furthest 2 pKa values for each amino acid group and divide by 2

13. Where is the buffer capacity at its greatest?

  • pH > pKa
  • pH = pKa
  • pH < pKa
  • pH = -pKa

14. What did Anfinson (1972) use to denature ribonuclease A?

  • Urea to solvate hydrophobic residues
  • Mercaptoethanol to reduce the disulfide bridges
  • Urea to solvate hydrophobic residues and mercaptoethanol to reduce the disulfide bridges
  • Mercaptoethanol to solvate hydrophobic residues and urea to reduce the disulfide bridges

15. The right-handed helix is more common but which way does it turn?

  • Anticlockwise
  • Clockwise

16. Which of these characteristics is NOT present in α-keratin?

  • Terminals create protofilaments and protofibrils
  • β-sheet pattern with several helices
  • "Coiled-coil" protein with 2 parallel right-handed helices
  • Stabilised by hydrophobic residue seam and sulfide bridges

17. Which of these is NOT a characteristic of collagen?

  • Triple helix with 33% Gly, 11% Ala, 15-30% Pro and non-standard Pro variations
  • No disulfide links, but contains modified crosslinks (covalent)
  • 2 polypeptide chains per molecule
  • Left-handed helices form right-handed coil

18. What is the acid dissociation constant (Ka)?

  • Ka = [H+][A-]/[HA]
  • Ka = [HA]/[H+][A-]

19. What characteristic is NOT present in β-sheets?

  • Pleated due to rippled edges (zigzag shape)
  • 2 residues repeat every 7Å
  • Twisted and pleated to make it less compact
  • Sheet arrangement with H bonds between backbone amides

20. What does pI mean?

  • It's the isoelectric point, meaning there is no net charge
  • It's the isoelectric point, meaning there is a positive net charge
  • It's the isoelectric point, meaning there is a negative net charge