chapter 2

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  1. Atom
    • Composed of protons, neutrons and electrons
    • Nucleus contains protons (+charge) and neutrons (no charge)
    • Electrons(- charge) occupy orbitals or shells outside nucleus
  2. Atomic mass
    sum of protons and neutrons in an atom
  3. atomic number
    number of protons in an atom
  4. Electron shells or orbitals
    layers around the nucleus
  5. Valence electrons
    • those in outermost shell
    • participate in chemical reaction and form bonds
  6. Isotopes
    • different forms of same atom
    • Atomic number is the same, but atomic mass is different
    • contain different numbers of neutrons
  7. covalent bonds
    • Occur when atoms share valence electrons
    • nonpolar - e are shared equally (H2 and O2)
    • polar - electrons are shared unequally (H20)
  8. Ionic bonds
    • when valence electrons are transferred from one atom to another form charged ions
    • Atom that loses electrons becomes cation (+charged)
    • Atom that gains electrons becomes anion (- charged)
  9. Hydrophilic molecule
    molecules are soluble in water because readily form hydration spheres
  10. Hydrophobic molecule
    • molecules are nonpolar,
    • cannot form hydration spheres
  11. Hydrogen bonds
    When H forms polar bond with another atom it takes on a slight + charge making it attracted to any nearby negatively charged atoms

    Adjacent H20 create surface tension
  12. Acids
    release protons (H+) in a solution (proton donor)
  13. Bases
    lower H+ levels of a solution (proton acceptor)
  14. bicarbonate buffer system in blood:
    H20 + C02 Û H2C03 Û H+ + HC03-
  15. Acidosis
    occurs if pH < 7.35
  16. Alkalosis
    occurs if pH > 7.45
  17. Functional groups
    • carbonyl group - ketones and aldehydes
    • hydroxyl group - alcohols
    • carboxyl group - organic acids (lactic and acetic acids)
  18. Stereoisomers
    • Differ in spatial orientation of a functional group
    • D isomers - right-handed
    • L isomers - left-handed
  19. Monosaccharides
    • simple sugars such as glucose, fructose, galactose
    • Only glucose is used as “metabolic fuel”
  20. Disaccharides
    • Sucrose - table sugar (=glucose + fructose)
    • Lactose - milk sugar (=glucose + galactose)
    • Maltose - malt sugar (=2 glucoses)
  21. Polysaccharides
    • many monosaccharides linked together
    • Include starch and glycogen
  22. Digestion of polysaccharides
    • Is reverse of dehydration synthesis
    • H+ added to one monosaccharide, OH- to other -- called hydrolysis
  23. Lipids - Triglycerides
    condensation of 1 glycerol and 3 fatty acids
  24. Saturated lipids
    hydrocarbon chains of fatty acids are joined by single covalent bonds
  25. unsaturated lipids
    there are double bonds within hydrocarbon chains
  26. cis fatty acid
    • 1 c=c with Hydrogens that share the double
    • bond on same side of fatty acid chain
    • This configuration makes the fatty acid bend
  27. trans fatty acids
    • 1 c=c with Hydrogens that share the double bond on opposite sides of fatty acid chain
    • This configuration makes the fatty acid straight
  28. Ketone Bodies
    • acidic, high lvl cause ketosis
    • Ketoacidosis occurs when ketone bodies in blood lower pH
  29. Phospholipids
    • lipids that contain a phosphate group
    • Phosphate part is polar and hydrophilic
    • Lipid part is nonpolar and hydrophobic
  30. Steroids
    • three 6-carbon rings joined to a 5-carbon ring
    • Cholesterol is precursor for steroid hormones
    • Is component of cell membranes
  31. Prostaglandins
    • fatty acids with cyclic hydrocarbon group
    • Produced by and active in most tissues
    • serve many regulatory functions
  32. Proteins - Amino Acids
    • made of long chains of amino acids
    • contain an amino group (NH2) at one end; carboxyl group (COOH) at other end
  33. Peptides
    • short chains of amino acids, linked by peptide bonds
    • Formed by dehydration reactions
  34. polypeptide
    <100 amino acids
  35. protein
    >100 amino acids
  36. Primary structure
    sequence of amino acids
  37. Secondary structure
    • caused by weak H bonding of amino acids
    • Results in alpha helix or beta pleated sheet shapes
  38. Tertiary structure
    • caused by bending and folding of polypeptide chains to produce 3-dimensional shape
    • Formed and stabilized by weak bonds between functional groups
    • can be denatured by heat, pH
  39. Quaternary structure
    forms when a number of polypeptide chains are covalently joined
  40. Nucleic Acids
    • Include DNA and RNA
    • made of long chains of nucleotides
    • consist of a 5-carbon sugar, phosphate group, and nitrogenous base
    • Bases are pyrimidines (1 ring) or purines (2 rings)
  41. DNA
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chapter 2
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