Chapter 6 - Proteins and Amino Acids

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Chapter 6 - Proteins and Amino Acids
2010-02-28 02:03:18
Nutrition Chapter 6 Proteins and Amino Acids

Chapter 6 - Proteins and Amino acids
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  1. Proteins
    • performs the body's work
    • provide energy (4Kcal/g)
    • chemical makeup
    • arranged in strands of amino acids
    • supply nitrogen to the body
  2. Chemical makeup of Proteins
    • carbon
    • hydrogen
    • oxygen
    • nitrogen
  3. structure of amino acids
    • acid group
    • amino group
    • side group
  4. Amino acids
    • 20 diffrent amino acids make up all proteins
    • nine essential amino acids
  5. 20 diffrent amino acids make up all proteins
    • analogous to letters of the alphabet
    • diffrent amino acids have diffrent side chains
  6. Nine essential Amino Acids
    must be taken in through the diet
  7. conditionally essential amino acids
    • Genetic disease - Phenylketonuria (PKU) - infants
    • Phenylalannine --> tyrosine
    • patients with PKU cannot meatbolize phenylaline
    • tyrosine becomes an essentail amino acid
  8. Protein synthesis
    DNA contains coded instructions for the amino acid sequence of proteins (Genetic code)
  9. How amino acids build proteins
    peptide bonds (link together amino acids)
  10. Structure and functional relationship of proteins
    • order of amino acids determines its ultimate shape
    • proteins final shape determines its funtion in the body
  11. Genetic defects
    • Genetic defects can also alter protein folding
    • example - sickle cell anemia
    • defect in protein hemoglobin (oxygen carring protein in RBCs)
    • sickle cell paintes have change in one amino acid ( valine -> glutamic acid)
  12. Denaturation
    unfolding of proteins
  13. digestion of proteins in teh stomach
    proteins are denaturated by cooking and or by acid in the sotmach
  14. Gastrin
    stimulates the release of acid and pepsin
  15. pepsin
    enzyme that breaks down proteins into smaller peptides
  16. Digestion of proteins in small intestine
    • pancrease release enzymes ( proteases) into small intestine
    • amino acids are ready for absorption
    • go to liver
  17. Proteases
    breaks down proteins into individual amino acids
  18. Role of Protein in the body
    • support growth and maintenance
    • building enzymes, hormones, antibodies
    • maintaing fluid and electrolyte balance
    • satlety
    • provide energy (not very important)
  19. Proteins and energy
    • contributes very little energy needs in healthy people
    • total amount of protein in the body remains constant
    • equilibrium = protine intake =protein excretion
  20. Postive protein balance
    • Protein intake is greater than protein excretion
    • growth
    • pregnancy
    • atheletic training
  21. Negative protein balance
    • protein intake is less than protein excretion
    • fasting
    • starvation
    • disease
  22. Conditions in which proteins are used for energy
    • starvation
    • disease states Ex. Diabetes
  23. Results in amino acid wasting
    your not using amino acids for their prupose
  24. Amino acid wasting
    • amino acids cannont be stored
    • body dose not have enough energy from other sources
  25. Another form of Amino acid wasting
    • body has movre protein than it needs
    • exceeds the body's need for protein synthesis
  26. Proteins in food - Animal Protein - 70% US Diet
    • beef
    • poultry
    • fish
    • milk
    • cheese
  27. Proteins in Food -Plant Proteins
    • also provides vitamins, minerals, fiber
    • nuts, beans, soy
    • limited saturated fat , no cholestrol
  28. Dietary Protein - high quality protein (complete)
    contains ample amount of all 9 essential amino acids
  29. Dietary Protein - low quality protein (incomplete)
    • deficeient or low in one or more essentail amino acids
    • limiting amino acid
  30. Complementary Proteins
    • two or more proteins combine to compensate for deficienes in essentail amino acid content in protein
    • THINK --> red beans and rice
  31. Is a High Protein Diet Harmful?
    • low in plant foods (fiber) vitamins, phytochemical
    • intake of animal protein increases risk for heat dieses
    • excessive intake of red meat in linked to colon cancer
    • burden on the kidneys
    • increase calcium loss
    • no more than 2X RDA protein
  32. RDA for Protein
    • increased by 10-15g/day for pregnancy
    • athletes may need 1.5-2g Kg body weight
    • most of US east more than the RDA for protein
    • excess protein cannot be stored
  33. Protein deficeny
    edema with maintance of some subtance for children
  34. Protein deficency
    Skin and bones apperance with little or no substance for tissue
  35. Vegetaria Diet
    • why become a vegetarian
    • vegans
    • fruitarian
    • lactovergeterians
    • lactoovovegetarians
    • concerns for infants and children