Biochem: Proteins

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Biochem: Proteins
2011-09-27 23:01:13
Srtuctures etc

Page 40-45
Show Answers:

  1. What is the result of a sequence of amino acids that has been disrupted; therefore causing an abnormal sequence?
    Abnormal sequence of amino acids specified for a particular protein results in misfolding of that protein, which in turn causes impairment of normal functioning.
  2. What are examples of secondary Structures of proteins and what type of bonds are used?
    • Alpha Helix
    • Beta Sheet

    Both are stabilized by extensive hydrogen bonding between the peptide bond carbonyl oxygens and amide hydrogens that make up the polypeptide backbone.

    Hydrogen bonding can also occur between two different chains
  3. What are the characteristics of the alpha helix?
    • - Possesses a "right hand turn"
    • - Each turn contains 3.6 amino acids
  4. What is the amino acid that interrupts the alpha helix and how?
    Proline produces a "kink" in the a-helix because it's structure is incompatible with the right hand spiral of the a-helix
  5. What is the characteristic feature of Beta Sheets
    They have a pleated appearance.
  6. What is the structure of globular proteins?
    What are the two different amino acids that must be in the structure?
    Nearly 1/3 of the amino acid residues are in turns or loops where the polypeptide chain reverses direction.

    The structure involves 4 amino acids, one of which must be proline or glycine.
  7. Serum albumin is what type of protein and what level of structure?
    Mostly alpha helices, tertiary structure
  8. Collagenase is what level of protein structure and what kind of protein?
    Mostly Beta strands, tertiary structure.
  9. Thymidylate synthase is what kind and level of protein structure?
    Mixed alpha helices and Beta strands, tertiary structure.
  10. What type of bonds stabilize tertiary structures?
    • Disulfide bonds
    • Hydrogen bonds
    • Ionic Bonds
  11. What determines the shape of secondary, tertiary functional protein?
    Interactions between the side chains of amino acids determines how a polypeptide chain folds into the intricate three-dimensional shape.