Module 3

  1. Acidic side groups
    Aparatic acid  Asp, D

    Glutamic acid  Glu, E
  2. Basic side groups
    Lysine    Lys, K

    Arginine     Arg, R

    Histidine        His, H
  3. Polar charged amino acid bases carry what charge?
  4. Polar charged amino acids carry what charge?
  5. All amino acids have carboxyl and amino parts, but if they become the what in proteins
    backbones in protein they are NOT available to participate in chemical reaction.
  6. Why can aspartic acid and glutamic acid participate in chemical reactions.
    Because the carboxyl part is in the side chain (-R group)
  7. How are lysine, arginine, and histidine able to participate in chemical reactions?
    If the amino part is in the side chain (-R) and can act as a proton acceptor in chemical reactions.
  8. What polar uncharged amino acid (hydrophilic) -R groups tend to have partial positive or negative charges?
    Serine     Ser, S

    Threonine      Thr, T

    Glutamine      Gln,   Q

    Asparagine      Asn,  N

    Tyrosine        Tyr,   Y
  9. Hydrophilic side chains tend to have partial + or - charge allowing them to
    participate in chemical reactions, form H-bonds, and associate with water.
  10. What are Nonpolar amino acids (hydrophobic) -R groups consist almost entirely of C and H atoms?
    Alanine   Ala, A

    Valine   Val,   V

    Leucine   Leu, L

    Isoleucine   Ile, l

    Methionine   Met, M

    Phynylalanine   Phe, F

    Tryptophan    Trp, W
  11. Who does hydrophobic -R groups want to associate with?
    Other hydrophobic R-groups or lipids.
  12. Nonpolar amino acids play an important role in membranes by
    associating with the membrane lipid bilayer.
  13. What makes nonpolar amino acids not free to participate in reactions?
    If S or N are present, they will be completely tied up.
  14. What are the four levels of protein structure?
    Primary - the sequence of amino acids

    Secondary - how that sequence if folded (a:helix, B: pleated sheet)

    Tertiary - how helices or sheets are arranged in three dimensions.

    Quaternary - arrangement of 3D structures into whole protein.
  15. Define Primary Structure
    the order in which amino acids are strung together with peptide bonds.
  16. The primary structure may be twisted or folded into a
    Secondary structure
  17. The Secondary structure of a protein is the
    coiling or folding of its polypeptide chains.
  18. a-helix
    "spiral staircase"
  19. Hair is an a-helical structure formed from the protein
    Keratin; Keratin is made up of three a-helices twisted together in a cable.
  20. Many proteins that span the membrane are made up of
    a-helices with the -R groups of hydrophobic (non-polar) amino acids associating with the hydrophobic lipids of the cell membrane and the -R groups of hydrophilic (polar) amino acids forming the pore.
  21. "B"- pleated sheets
    are found in many proteins in nature (such as spider silk) but are less common in human proteins.
  22. Protein Structure illustrated.  Helices, pleated, amino acids that don't have secondary structure.
    a-helices are represented as coils

    B-pleated sheets are represented as arrow (arrow points amino)

    Amino acids that don't have secondary structure are threads
  23. Tertiary structures within proteins are
    formed when separated chains, or different a-helices, or other parts of chains are joind together into a larger, folded structure.
  24. Types of atomic interactions leading to Tertiary structure
    Ionic bonds

    Hydrophobic interactions

    Van der Waals interactions ("shapes" of molecules fit each other like puzzle pieces)

    Disulfide bridges (are formed between cysteines. Cysteine is the only amino acid with an -SH group.

    Hydrogen bonds
  25. Heme group
    an iron-containing group which holds onto the oxygen molecule.
  26. Hemoglobin
    the oxygen-carrying protein of the blood.
  27. The proper function of hemoglobin depends critically on
    primary, secondary, tertiary and quaternary structure.  Any alteration in the protein at any of these levels causes disease
  28. Primary, secondary and tertiary structure, combine together into a
    quaternary structure.
Card Set
Module 3