1. UNIT 2: Metabolic Processes Intro to Metabolism, Energy, ATP and Redox

2. Metabolism Living organisms must constantly capture, store and use energy to carry out the functions of life. At any given instant an organism is breaking down macromolecules(catabolic reactions) to release energy, and synthesizing macromolecules (anabolic reactions) which requires energy. The sum of all anabolic and catabolic processes in a cell or organism is called METABOLISM.

3. Energy Transfer Energy is not easy to obtain; often it is captured in one form and converted to another before it is used. Ex. Plants use photosynthesis to convert light energy to glucose. Ex. Plants and animals use cellular respiration to change macromolecules, like carbohydrates, into a source of useable energy, ATP.

4. The First Law of Thermodynamics The total amount of the energy in the universe is constant. Energy cannot be created or destroyed, but only converted from one form to another. Energy Chemical Potential energy is energy stored in bonds. Free energy is energy that can do work. It is _____________ when a bond is broken and _____________ when a new bond is made.

5. ATP: Useable Energy ATP is a prime energy carrying molecule. ATP is used to create free energy for the cell. ATP is a nucleotide composed of adenine (nitrogenous base), ribose (pentose) and three phosphate groups (P groups).

6. Hydrolysis of ATP The removal of the terminal P group from ATP by hydrolysis in the presence of ATPase (enzyme), forms ADP and an inorganic phosphate group (P i ) and releases free energy for the cell. ATPase

7. Phosphorylation The energy is not given off as heat or the cell would die. It is immediately coupled with a reaction which uses the energy. Phosphorylation: the terminal P, and it’s high energy bond, are attached to a new molecule. Phosphorylation makes the molecule more reactive.

8. Phosphorylation An example of this process is in active transport, ATP’s phosphate group is removed and then phosphorylated to protein carriers, changing their shape and letting ions into or out of the cell against the concentration gradient.

9. Redox Reactions (Biol.Rxn Type #3) Much of the ATP created by the cell is a result of redox reactions; a reaction in which one atom transfers an electron/electrons to another atom. Oxidation and reduction both occur. Oxidation: a process in which an atom loses one or more electrons (aka: the Reducing agent) Reduction: a process in which an atom gains one or more electrons (aka: the Oxidizing agent) LEO the lion says GERor OIL RIG

10. Oxidation-Reduction Reactions

11. Ionic Reactions Redox is easily seen in ionic reactions.

12. Redox in Covalent Systems Redox is more difficult to see in a covalent system. In covalent systems reactions, the unequal sharing of electrons in a polar bond is considered to be a loss or a gain of electrons. Easiest to see in combustion reactions (fig 13 p67): CH 4 (g) + 2O 2 (g) --> CO 2 + 2H 2 O + Energy Diagram:

13. Redox in Metabolism Redox reactions often occur in a chain. This is what happens in metabolism. The electron(s) are moved to successively better oxidizing agents. (ex Electron Transport Chain)