BIC Lecture 2

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BIC Lecture 2
2014-09-06 19:48:49
Test One
Show Answers:

  1. What can proteins do?
    latch on to substances that are not soluble to help transport them
  2. What can amino acids form and why?
    Can form isomers but only two can get incorporated into proteins
  3. What is the backbone of amino acids?

    Explain the groups.
    anything but the R group

    two are ionizable -- they have a proton that they aren't permanently attached to (the primary amino group and the primary -COOH group)
  4. Explain the groups in terms of pH.
    In acidic solutions, COOH is constantly letting go of its proton. However, it is being reprotonated just as quickly. At a higher pH, (2-4), this reprotonation ceases; and, the amino acid exists as a zwitterion.
  5. If we are taking an ionizable group through titration, what is happening?
    protons are being pulled away from these groups as --OH scavenges for H+ to form water
  6. Define pKa.
    describes the strength of an acid

    describes the susceptibility of a proton to removal by reaction with a base
  7. Why are there three letter abbreviations and one letter abbreviations?
    Three letters: RNA reads it in three nucleotides (codons)

    One letter: condenses protein structure
  8. In acid, how does an amino acid exist?
    with both ionizable groups protonated
  9. In base, how does an amino acid exist?
    with both ionizable groups deprotonated
  10. An increase in pH from acid causes?
    the formation of a carboxylate
  11. What is the inflection point? What occurs at it?
    A point on a chart that marks the beginning of a significant move, either up or down

    the amino acid form changes from either protonated--> zwitterion  or zwitterion--> deprotonated
  12. In acid base chemistry, what is the proton donor? proton acceptor?
    • proton donor: acid
    • proton acceptor: base
  13. Definition of pH
    pH=log(1/[H+])= -log [H+]
  14. Definition of pKa (formula)
  15. At the halfway point, what is occurring?
    the concentration of conjugate base equals that of the acid
  16. What are some functions of proteins?
    • conversion of energy
    • muscle contraction
    • enzymes
    • transport
    • structural support
    • immune response
    • messengers
    • growth and development
    • motion
  17. __ is the most abundant protein. 

    __ and __ function in structural support.

    collagen and keratin
  18. What is the difference between secondary and tertiary structure?
    secondary: interaction is localized; between adjacent amino acids

    tertiary: different regions will react together
  19. What is quaternary structure?
    multiple subunits brought together
  20. How many atoms are involved in amino acids?
    • five: -NH3+
    • - COO-
    • R
    • alpha carbon
    • Hydrogen
  21. How many different R groups are there?
    20, but glycine has just a simple hydrogen, so technically nineteen