The Chemistry of Life

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Chapter 2

• The Chemistry of Life

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2.1 The nature of matter

• Atom the smallest particle of an element that
  has the properties of that element
• Atom is made of three subatomic particles
• Proton Positive, nucleus
• Electron Negative, outside nucleus in energy
  levels
• First energy level -- 2e
• Second energy level -- 8e
• Third energy level -- 18e
• Neutron No charge, nucleus

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• Number of protons usually is equal to the number
  of electrons so that the overall charge of an
  atom is neutral!! 
• If atoms of the same element have different
  number of neutrons, they are called isotopes!
  EX. C - 12 , C - 13, C - 14
• When two or more atoms of different elements are
  chemically combined you create what is called a
  compound. EX. Water

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Compounds can be made with three different kinds
of bonds

• Covalent
• Share electrons to be stable
• Strongest and most common bond
• Molecule group of atoms held together with
  covalent bonds with no overall charge
• Van der Waals forces (what holds molecules
  together)

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• Ionic
• Gain / lose electrons to be stable
• Ion a charged particle
• Less abundant in living things than covalent
  bonds
• Hydrogen

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Mixtures Solutions

• Mixture a combination of substances in which
  the individual components retain their own
  properties
•  Solution a mixture in which one or more
  substances are distributed evenly in another
  substance
• Two parts to every solution
• Solute --- What is being dissolved
• Solvent -- What is doing the dissolving Most
  common... WATER

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pH

• pH a measure of how acidic or basic a solution
  is
• Acid substance that forms H ions in water
• 0 - 7
• Base substance that forms OH- ions in water
• 7 14

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Acids Bases

• Acids

• Bases

• Higher concentration of H ions
• pH value less than 7
• Sour taste
• React with metals
• Blue litmus paper will turn red if an object is
  an acid

• Lower concentration of H ions
• pH value more than 7
• Bitter taste
• Slippery
• Turn red litmus paper blue if an object is a base

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2.2 Water and Diffusion

• Perhaps the most important compound in living
  organisms is water!
• Properties of water
• Polarity
• Has a positive and negative end
• Gives water its dissolving property
• Resists Temperature Changes
• Water expands when it freezes
• Adhesion ? Graduated cylinder
• Adhesion is greater between glass water than
  water water!

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2.3 Carbon Compounds

• The one element that defines living organisms is
  Carbon!
• Carbon has four electrons in its outermost shell
  therefore, it can combine with almost every other
  element
• Any compound that contains carbon is considered
  to be an organic compound!
• If it does not contain carbon it is inorganic.

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Four types of Organic compounds

• Carbohydrates
• Made of C, H, O (C to H ration is 2 to 1)
• Monomer monosaccharide
• Function Provide quick energy
• EX. Glucose how animals store food
• Starch how plants store food
• Cellulose composes cell walls of plants

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2) Lipids

• Made of C, H, O --- (C to H ratio higher than 2
  to 1)
• Monomer Glycerol 3 fatty acids
• Function 1) Store energy 2) Insulation 3)
  Protection
• EX. Fats and Oils

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3) Proteins

• Made of C, H, O, N, Sulfur
• Monomer Amino Acid
• 20 AA
• Function 1) Build Muscle 2)Transportation
  (blood -- hemoglobin) 3) Speed up
  chemical reactions (enzymes)

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4) Nucleic Acids

• Made of C, H, O, N, Phosphorus
• Monomer Nucleotide
• Function Store genetic information
• EX. DNA (Deoxyribose Nucleic Acid) Master
• RNA (Ribose Nucleic Acid) -- Copy of DNA

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2.4 Chemical Reactions and Enzymes

• Chemical reaction changes one set of chemicals
  into another set of chemicals
• Chemical reactions have two parts
• Reactants
• Products
• CO2 H2O ? H2CO3
• Reactants Product

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Enzymes

• Enzymes are proteins that act as a biological
  catalyst.
• Catalyst a substance that speeds up the rate of
  chemical reaction
• Enzymes speed up chemical reactions that take
  place in the cell.

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Enzyme Action

• The enzyme-substrate complex
• Enzymes are substrate specific.
• They act like a lock and key.
• Enzymes will only catalyze their substrates.
• Regulation of Enzyme Activity
• Enzymes can be affected by
• Heat
• pH
• Concentration of Substrate
• Proteins that turn enzymes on and off

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Example of what an enzyme does! How enzymes
work Potato Peroxide ? water oxygen (catalase)
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Where are enzymes?

• Enzymes regulate many chemical reactions such as
• Photosynthesis
• Cellular respiration
• Digestion
• Enzymes are reusable
• Once they work with one substrate they release
  and go to another substrate.