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Protein Digestion exam

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  • Where does most protein digestion occur?
    In the stomach and small intestine.
  • Pepsin
    A protease enzyme in the stomach that breaks down denatured proteins into peptides.
  • What is the primary goal of protein digestion?
    To break dietary proteins into single amino acids for absorption.
  • Amino Acid Pool
    All of the body's amino acids that are readily available for use.
  • What role does stomach acid play in protein digestion?
    It denatures proteins and activates pepsin.
  • Protein Turnover
    The ongoing process of breaking down and rebuilding proteins in the body.
  • Are proteins chemically digested in the mouth?
    No, only mechanical digestion occurs in the mouth for proteins.
  • Pancreatic Proteases
    Enzymes from the pancreas that further digest peptides in the small intestine.
  • What happens to peptides in the small intestine?
    They are broken down into dipeptides, tripeptides, and amino acids.
  • Dipeptidases and Tripeptidases
    Enzymes in enterocytes that break dipeptides and tripeptides into single amino acids.
  • What are the three primary fates of absorbed amino acids?
    Used to build new proteins, make nitrogen-containing compounds, or be deaminated for energy.
  • Deamination
    The removal of the amine group from an amino acid, allowing it to be used for energy.
  • How are amino acids absorbed?
    As single amino acids through the small intestine into the bloodstream.
  • What is the effect of protein turnover on dietary protein needs?
    It reduces the amount of dietary protein required.
  • Protease
    An enzyme that breaks down proteins into smaller peptides or amino acids.
  • What activates pepsinogen in the stomach?
    Stomach hydrochloric acid (HCl).
  • Mechanical Digestion of Protein
    Chewing in the mouth that physically breaks down protein food.
  • What is the function of the amino acid pool?
    To supply amino acids for protein synthesis and other metabolic needs.
  • Non-protein Nitrogen Compounds
    Molecules like some hormones that contain nitrogen but are not proteins.
  • What happens to old or damaged proteins in the body?
    They are degraded and their amino acids are recycled through protein turnover.
  • Enterocytes
    Cells lining the small intestine that absorb amino acids and contain peptidases.
  • What is the significance of protein turnover for cellular adaptation?
    It allows cells to quickly degrade unneeded proteins and synthesize new ones as needed.
  • Peptide
    A short chain of amino acids linked by peptide bonds.
  • How do dietary proteins contribute to the amino acid pool?
    By being digested and absorbed as amino acids into the bloodstream.
  • Hydrochloric Acid (HCl)
    Stomach acid that denatures proteins and activates pepsinogen.
  • What is the fate of amino acids not used for protein synthesis?
    They may be used to make nitrogen compounds or be deaminated for energy or converted to glucose/fat.
  • Why is protein digestion necessary?
    Because only single amino acids can be absorbed and used by the body.
  • What is the estimated amount of protein turned over daily in the body?
    About 250 grams per day.