Biochemistry_1_ by malj


									                  The Chemistry of Life

                     What are living
                   creatures made of?

                    Why do we have
                        to eat?

Regents Biology                 2006-2007
                  Chemistry in Biology
Chapter 6
                  6.1 Atoms, Elements, and Compounds
    1. Atoms
      § Chemistry is the study of matter.
       A. Atoms are the building blocks of matter.
       § Neutrons and protons are located at the
         center of the atom.
           1. Protons are positively charged
           2. Neutrons are particles that have no
Regents Biology
              Chemistry in Biology
Chapter 6
             6.1 Atoms, Elements, and Compounds
               3. Electrons are negatively charged
               particles that are located outside the

 Regents Biology
                  Chemistry in Biology

   6.1 Atoms, Elements, and Compounds
    2. Elements
      § An element is a pure substance that cannot
        be broken down into other substances by
        physical or chemical means.
      § There are over 100 known elements, 92 of
        which occur naturally.
       § Each element has a unique name and

Regents Biology
                  Chemistry in Biology

   6.1 Atoms, Elements, and Compounds
    The Periodic Table of Elements
         § Horizontal rows are called periods.
         § Vertical columns are called groups.

Regents Biology
   3. Elements of Life
     § 96% of living
        organisms is
        made of:
         n   carbon (C)
         n   oxygen (O)
         n   hydrogen (H)
         n   nitrogen (N)

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   What is a Molecule
     Covalent bonds hold 2 or more atoms
      together to form a molecule.
         A. Important Molecules
         u H 2O       Water
         u O2         Oxygen
         u CO2        Carbon Dioxide
         u C6H12O6    Glucose

Regents Biology
   Why do elements form molecules.
    1. To fill their outer shell with electrons.
    2. This is called bonding.
    3. Two types of bonding
        a. covalent = Sharing
        b. ionic = Transferring
     4. Molecules are formed by covalent

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   4. Macro-molecules of Life
     A. Put C, H, O, N together in different
       ways to build living organisms
     B. What are bodies made of?
         1. carbohydrates
              § sugars & starches
         2. proteins
         3. fats (lipids)
         4. nucleic acids
              § DNA, RNA

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   How do we make these molecules?

                  We build them!

Regents Biology                    2006-2007
   Why do we eat?
    § We eat to take in more of these chemicals
         u   Food for building materials
              § to make more of us (cells)
              § for growth

              § for repair
         u   Food to make energy
              § calories
              § to make ATP

Regents Biology
   What do we need to eat?
    § Foods to give you more building blocks
        & more energy
              § for building & running bodies
         u carbohydrates
         u proteins

         u fats

         u nucleic acids

         u vitamins

         u minerals, salts

         u water
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§ What do all      C. They all contain Carbon
macromolecules       1.   Has 4 valence electrons
have in common?      2.   Forms many types of
                          covalent bonds.
                     3.   Forms the backbone of
                          all macromolecules

 Regents Biology
Regents Biology
What do all
                     2. They are all polymers
have in common?        u   A polymer is a long
                           molecule consisting of
What is a polymer?         many similar building
                           blocks called

What is a            3. They are all assembled by
monomer?                 a Dehydration reaction

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How are polymers                       Dehydration Reaction
assembled?                             (Condensation) Water Making

                   HO     1        2      3   H    HO           H

                          Short polymer            Unlinked monomer

                   Dehydration removes a water
                                                         H 2O
                   molecule, forming a new bond

                         HO    1        2     3    4     H
                                    Longer polymer
     Figure5.2A    (a) Dehydration reaction in the synthesis of a polymer

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How are                      § Polymers are disassembled
polymers taken                  by
                                  u   Hydrolysis (water Breaking)

                                 HO     1       2         3   4    H

                            Hydrolysis adds a water
                                                                   H 2O
                            molecule, breaking a bond

                           HO     1      2       3        H   HO          H

             Figure 5.2B    (b) Hydrolysis of a polymer

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   Building large molecules of life
    § Chain together smaller molecules
         u   building block molecules = monomers

     § Big molecules built from little molecules
         u   polymers
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    Building large organic molecules
§ Small molecules = building blocks (Monomers)

§ Bond them together = polymers

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    Building important polymers
Carbohydrates = built from sugars(saccharides)
     sugar – sugar – sugar – sugar – sugar – sugar

    Proteins = built from amino acids
     amino amino amino amino amino amino
      acid – acid – acid – acid – acid – acid

    Nucleic acids (DNA) = built from nucleotides
     nucleotide – nucleotide – nucleotide – nucleotide
 Regents Biology
   How to build large molecules
    § Synthesis (Dehydration)
         u building bigger molecules
           from smaller molecules
         u building cells & bodies

              § repair
              § growth
              § reproduction

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   Example of synthesis

      amino acids                          protein
§ Proteins are synthesized by bonding amino acids
                  amino acids = building block
Regents Biology        protein = polymer
   How to take large molecules apart
    § Digestion (Hydrolysis)
         u taking big molecules apart
         u getting raw materials

              § for synthesis & growth
         u   making energy (ATP)
              § for synthesis, growth & everyday functions


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   Example of digestion

                                   ATP      ATP

                          ATP               ATP
          starch            glucose
 § Starch is digested to glucose
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     gone bad!

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   Old Food Pyramid

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   New Food Pyramid

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   Don’t forget water
     § Water
         u 65% of your body is H2O
         u water is inorganic

              § doesn’t contain carbon
     § Rest of you is made of carbon molecules
         u   organic molecules
              § carbohydrates
              § proteins
              § fats
              § nucleic acids
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