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CHEMISTRY for BIOLOGY

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					               CHEMISTRY for
                 BIOLOGY



22 Aug. 2012       Chemistry.ppt   1
         CHEMISTRY for BIOLOGY


• Atomic structure, ionic bonding previously
  studied. Review in text if necessary.




22 Aug. 2012       Chemistry.ppt               2
               CHNOPS




22 Aug. 2012    Chemistry.ppt   3
               CHNOPS
 • CHNOPS elements usually form covalent
   bonds.
 • Electrons shared à stability




22 Aug. 2012      Chemistry.ppt            4
    Examples of covalent bonding




22 Aug. 2012   Chemistry.ppt       5
                             Carbon
   • Carbon atoms form covalent bonds to carbon
     atoms.
   • Carbon chains form "backbones" of organic
     molecules.
      – Various lengths
      – "Functional groups" may be attached to
        carbon chains.
               • determine properties of molecules
               • cause diversity of organic molecules

22 Aug. 2012                   Chemistry.ppt            6
               "Functional groups:"
                   4 to know




22 Aug. 2012          Chemistry.ppt   7
                 "Functional groups"
  • Any or all functional groups may be
    attached to a carbon backbone to make
        –   alcohols,
        –   acetic acid,
        –   fatty acids,
        –   sugars,
        –   amino acids,
        –   etc.

22 Aug. 2012               Chemistry.ppt    8
  CARBOHYDRATES, FATS, and
         PROTEINS
 • Simple molecules built by covalent bonding
   and addition of functional groups.
 • Biological polymers built of simple
   molecules
       – Assembled and disassembled in a regular way.




22 Aug. 2012            Chemistry.ppt               9
               CARBOHYDRATES
     • Monosaccharides = "Simple sugars"
           – glucose, fructose, etc.
     • Disaccharides
     • Polysaccharides




22 Aug. 2012                Chemistry.ppt   10
               CARBOHYDRATES
• "Simple sugars" = monosaccharides
• Used as cellular "fuel," source of energy
     – (as gasoline for engine)




22 Aug. 2012                Chemistry.ppt     11
                Disaccharides:
Monosaccharide molecules react to form disaccharides.




22 Aug. 2012          Chemistry.ppt               12
    Synthesis = dehydration synthesis
 • Removal of OH + H forms water, H2O
 • Leaves bonding sites that join
   monosaccharide units.




22 Aug. 2012      Chemistry.ppt         13
               Disassembly = hydrolysis
• Break bond between monosaccharide units.
• Add OH + H to fill bonding sites.




22 Aug. 2012            Chemistry.ppt     14
               Polysaccharides
• Built up of monosaccharide units by dehydration
  synthesis.
• Disassembly by hydrolysis.




22 Aug. 2012          Chemistry.ppt                 15
                 Polysaccharides
• Examples:
     – Glycogen - stored fuel in liver, muscle cells
     – Starch - stored energy in plants, digestible
       (hydrolysis)
     – Cellulose - plant cell walls, indigestible (dietary
       fiber)
     – Chitin - arthropod exoskeletons, indigestible


22 Aug. 2012              Chemistry.ppt                 16
                       FATS
• Assembled of glycerol + 3 fatty acids by
  dehydration synthesis.
• Glycerol = 3-carbon chain with 3 hydroxyl
  groups
• Fatty acid = long carbon backbone with
  carboxyl group at one end
     – bonding sites at sides filled with hydrogen

22 Aug. 2012             Chemistry.ppt               17
                   Triglyceride
• Dehydration
  synthesis
    – Remove H from
      glycerol and OH
      from fatty acids
    – Leaves sites to form
      ester bond
• Hydrolysis
    – Add H + OH
    – Break ester bond
22 Aug. 2012             Chemistry.ppt   18
                       LIPIDS
 • Larger group containing fats
 • Fats
       – mostly “saturated” fatty acids,
       – solid at room temperature
 • Oils
       – some “unsaturated” fatty acids,
       – liquid at room temperature
 • Waxes
       – larger poly-alcohols with long chain fatty acids
22 Aug. 2012              Chemistry.ppt                19
                           LIPIDS
   • Phospholipids
         glycerol
         + 2 fatty acids
         + 1 phosphate-
         containing acid




22 Aug. 2012                Chemistry.ppt   20
                          LIPIDS
• Steroids
     – unlike other lipids,
       4-ring structure




22 Aug. 2012                  Chemistry.ppt   21
                PROTEINS




   • Proteins are polymers of amino acids
      – amino acid structure
      – “R” can be anything
22 Aug. 2012        Chemistry.ppt           22
               Amino acids




 • Examples:
 • 20 “R” groups à 20 kinds of amino acids
   in all biological chemistry.

22 Aug. 2012      Chemistry.ppt              23
                        PROTEINS
   • Globular                           • Structural/Fibrous
         – hemoglobin                           – keratin
         – myoglobin                               • epidermis, hair, nails
         – hormones                             – collagen
               – insulin, glucagon,                • tendons, ligaments
                 growth hormone                 – silks
         – antibodies
         – receptors
         – ENZYMES

22 Aug. 2012                    Chemistry.ppt                                 24
               PROTEINS: ENZYMES
    • Biological polymers (carbohydrates, lipids,
      proteins, nucleic acids) must be assembled
      precisely!!
          – Chemical processes must occur in proper sequence.
          – Chemical processes require energy (heat) for
            activation.
               • Reactions occur very slowly at body temperature.
               • Add heat to speed up reaction à undesirable reactions
    • How to control reactions at moderate
      temperature?
       – Answer = . . .
22 Aug. 2012                     Chemistry.ppt                           25
                            ENZYMES
• Enzymes = biological
  catalysts
     – Properties
        • SPECIFICITY:
               – 1 enzyme à 1 reaction
           • LOWER ACTIVATION
             ENERGY:
               – increased reaction rate
           • CONTROL (regulation):
               – Enzymes can be “switched
                 on” or “off.”

22 Aug. 2012                       Chemistry.ppt   26
 Process of catalysis:
    • Enzyme attaches
      temporarily to
      substrate(s) at active
      site.
    • Reaction occurs.
    • Product released.




22 Aug. 2012             Chemistry.ppt   27
               Importance of enzymes

• Enzymatic reactions
  occur in sequence to
  make natural
  products.
• Abnormal enzymes
  can produce
  abnormal products.



22 Aug. 2012             Chemistry.ppt   28
                     Nucleic acids
   • Polymers of
     nucleotides
         – 3 parts of
           nucleotide
            • 5-C sugar
              (ribose,
              deoxyribose)
            • Base (A, C, G,
              T or U)
            • Phosphate


22 Aug. 2012                   Chemistry.ppt   29
                  Nucleic acids
• Base pairing in DNA
     – A with T
     – C with G
• Information storage
• Stability




22 Aug. 2012            Chemistry.ppt   30
                      ATP

 • A special nucleotide
 • Primary “fuel” for
   cell metabolism.




22 Aug. 2012          Chemistry.ppt   31

				
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