CHEMISTRY OF LIFE

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CHEMISTRY OF LIFE
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BIOLOGY-THE STUDY OF LIFE
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The Chemistry of Life

• I. Organization of Atoms
• Bonds
• Water Molecules
• Classification of Compounds
• V. Compounds found in living things.

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I. Organization of Atoms

• Atom- the smallest unit of matter that cannot be
  broken down by chemical means.
• Protons- positive charge, located in the nucleus.
• Neutrons- no charge, located in the nucleus.
• Electrons- negative charge surrounding the
  nucleus in a cloud.

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I. Organization of Atoms

• Element- a pure substance made of only one kind
  of atom.
• Compound- a substance made of the joined atoms of
  two or more different elements. Ex. NaCl (Sodium
  Chloride)
• Molecule- a group of atoms held together by
  covalent bonds.

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I. Organization of Atoms

• Ion- an atom or molecule that has gained or lost
  one or more electron. Ions have an electric
  charge because they contain an unequal number of
  electrons and protons.
• Positive charge- atom that has lost an electron.
• Negative charge- atom that has gained electrons.

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II. Bonds

• Ionic Bonds- when ions of opposite charges
  interact. Ex. Sodium chloridean atom of sodium
  is unstableonly 1 electron in the outer shell
  (valence electron). An atom of chlorine is
  unstable because it has 7 valence electrons. The
  atoms are readily attracted to each other.

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II. Bonds

• Covalent bonds form when two or more atoms
  share electrons. (very strong bonds --super
  glue)
• Hydrogen bonds a weak chemical attraction
  between polar molecules. Ex. A water
  moleculeH2O.

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III. Water Molecules

• The electrons in a water molecule are shared by
  oxygen and hydrogen atoms.
• B. A water molecule has positive and negative
  ends, thus polar.

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III. Water Molecules

• C. Particles are able to dissolve readily in
  water due to its polarity. Thus, the universal
  solvent.

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III. Water Molecules

• D. Cohesion an attraction between substances of
  the same kind. The hydrogen bonds between water
  molecules cause the cohesion of liquid water
  molecules at the surface of water (like holding
  hands).this attractions is surface tension

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III. Water Molecules

• E. Adhesion attraction between different
  substances. Ex. Water molecules moving upward
  through the stem of a plant.

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III. Water Molecules

• F. Evaporative cooling Water heats more slowly
  and retains heat longer. Organisms release heat
  through water evaporative cooling (sweat).

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IV. Classification of Compounds

• Organic- compounds containing carbon (with
  hydrogen). Ex. Plants, animals
• Inorganic- compounds that do not contain carbon.
  Ex. Air, water, minerals

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V. Compounds Found in Living Things
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CHO CHO CHON CHONP
CHO CHO CHON CHONP
CHO CHO CHON CHONP
CHO CHO CHON CHONP
CHO CHO CHON CHONP
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Carbohydrates

• A key source of energy
• Building blocks are simple sugars-
  monosaccharides (glucose fructose)
• Disaccharides
• Polysaccharides

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Lipids

• Stored energy (mostly in animal-some plant seeds)
• Nonpolar molecules
• Fats, oils, steroids, and waxes
• Phospholipidsmake up the lipid bilayer of cell
  membranes

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Proteins

• Important for structural functions
• Skin, ligaments, tendons, muscles, hair
• Anitibodies, hemoglobin, hormones, enzymes
• Building blocks are amino acids
• 20 different amino acids are found in living
  things

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Nucleic Acids

• Contain all genetic, hereditary information
• DNA, RNA
• Building blocks are nucleotides