Macromolecules are large molecules made up of repeating subunits. Subunits are joined together by covalent bonds. Anabolic reactions involve the creation of macromolecules from smaller subunits. Catabolic reactions involve the breakdown of macromolecules into smaller subunits. These reactions usually involve a catalyst, called an enzyme.

 Also called dehydration synthesis reaction.  Anabolic  Always involve the creation of water.  REQUIRE energy.

 Involves the removal of hydrogen from one end of a subunit and the removal of a hydroxyl group from the other end of the other subunit. H HO OH HO energy H H2OH2O O O O HO O O

 Reverse condensation reactions.  Catabolic  Involves the breaking of macromolecules into subunits by the addition of water.  RELEASE energy. HHO H2OH2O H OH HO energy

 A reaction in which one atom transfers an electron/electrons to another atom. Oxidation and reduction both occur.  Oxidation: an atom loses one or more electrons.  Reduction: an atom gains one or more electrons.

 Easily seen in ionic reactions:  Na + Cl  [Na] + [Cl] -

 Oxidizing agent: the substance that gains an electron; it forces another atoms to become oxidized.  Reducing agent: the substance that loses an electron; it forces another atom to become reduced.

 Also happen in covalent systems, even though the electrons are not transferred.  The unequal sharing of electrons in a polar bond is considered to be a loss or a gain of electrons.  Ex. process of energy conversion, ex. cellular respiration and photosynthesis.

 In the living cell, neutral is better, the body uses buffers to resist significant changes in pH.  Buffers are chemical systems that can donate/remove H+ ions when required to shift a solution from being too acidic or basic.  The products of a neutralization reaction are water and a salt.  NaOH (s) + HCl (g) --> H 2 O (l) + NaCl (aq) ‏