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  1. Structure of proteins, what elements does it contain and of what amino acids?
    C, H, O, and N

    Carbon = acid group

    Hydrogen = n/a

    Nitrogen group = amine

    *side chain, "R" portion determines protein name
  2. Amino Acids (AA) characteristics: essential, nonessential, and conditionally essential AA.

    Give info. on each of the (3)
    Essential: (9) Must be taken in via food (i.e. body cannot produce)

    Non-essential: (11) Body can produce so consumption of these isn't necessary

    Conditionally ess. AA: Essential during infancy, disease or trauma
  3. What is the synthesis of non ess. AA?

    What is its function?
    • Transamination: Transfer of an amine group (Nitrogen) to a carbon skeleton to form a new amino acid.
  4. What is the synthesis of Non ess. AA and AA Degradation?
    Degradation: AA losing an amine group (N)

    Amine group is incorporated into urea in the liver.

    -->Urea then is excreted in urine via the kidney.
  5. Complete & Incomplete proteins. What are they? And what are complementary proteins?
    Complete: adequate amount of all the essential AA (animal protein except gelatin)

    Incomplete: Inadequate amounts of the ess. AA (plant proteins except soy)

    Complementary: Combining plant proteins to compensate for limiting AAs (red bean & rice, adding legumes to grains)
  6. What type of bond links amino acids to form proteins? What proteins do they form? (4)
    peptide bonds

    • 1) Dipeptides (2 AA)
    • 2) Tripeptides (3 AA)
    • 3) Oligopeptides (4-10 AA)
    • 4) Polypeptides (>10 AA)
  7. What is Transcription and Translation?
    Transcription: forming mRNA from DNA

    Translation: converting mRNA to protein (step 4)
  8. Summary of protein synthesis; 4 steps, with the 4th step having 4 substeps.
    • 1) DNA unwinds allowing enzymes access.
    • 2) Transcription (DNA-->mRNA)
    • 3) mRNA is processed and goes to the cytosol.
    • 4a) Ribosomes recognize start date.
    • 4b) Transfer RNA (tRNA) carries AAs to ribosomes when needed.
    • 4c) Protein is made by added 1 AA at a time
    • 4d) Protein is finally released from ribosome.
  9. Protein organization.

    Primary: Sequence of chain of AA

    Secondary: Due to H or S bonds between AA.

    Tertiary: Occurs from additonal folding and determines protein function.

    Quaternary: Occurs when multiple proteins join together.
  10. Denaturation & Turnover of protein. What are they?
    Denaturation: Altering protein's tertiary structure (3-d structure).

    Acid, alkaline, heat, enzymes & agitation can all cause denaturation.

    Protein turnover: Constant state of synthesis, breakdown, rebuilding and repair.

    Protein turnover is generally high.
  11. Sources of protein. In the US and worldwide, what percentage is supplied by meat, poultry, fish, milk & milk products, legumes & nuts?
    70% in the US.

    Worldwide, 35% comes from animals.
  12. Evaluation of food proteins are valued by what two concepts?

    • Biological Value: measure of how effecient dietary protein is converted to body tissue protein.
    • BV = N retained / N absorbed x 100

    Protein Efficiency Ratio (PER):
    measure of weight gain in lab animals.

    PER = weight gain (g) / protein consumed
  13. Evaluation of food protein (cont'd). Define the Chemical Score and the Protein Digestibility Corrected AA Score.
    Chemical Score: compares ess. AA composition to reference protein (egg white)

    CS = mg of limiting AA per g protein / mg of limiting AA per g of reference protein.

    PDCAAS: Chemical Score x digestibility


    DV considers the PDCAAS
  14. Protein RDA (recommended daily avg)

    Do most americans consume a good excess of their protein requirements?
  15. Nitrogen balance: positive, equilibrium, and negative nitrogen balance.

    Explain the intake/excretion of nitrogen for each.
    Pos: N intake down, while N excretion is high.

    balances = healthy adult meeting protein & energy needs.

    N intake up, while N excretion is low.
Card Set:
2011-10-05 07:01:18

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