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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?
8. Which isomer occurs naturally?
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?
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