Thursday 20 October 2011

20 Notes - An Introduction to Metabolism

- Metabolism is the sum of all anabolic and catabolic processes in a cell or organism that uses energy to produce work
- Potential Energy is stored energy that is eventually converted into kinetic energy
- The First Law of Thermodynamics: energy cannot be created or destroyed, it can also be converted
- A potential energy diagram shows the changes in energy during a chemical reaction, including the amount of energy required to break molecular bonds (activation energy)
- Exergonic reactions are spontaneous (change in G is negative) and endergonic reactions are not spontaneous

- The Second Law of Thermodynamics: The entropy of the universe increases with any change that occurs
- Entropy is the measure of randomness or disorder in energy or a collection of objects
- Energy and Entropy determine whether a given chemical or physical change will occur spontaneously
- Gibbs free energy: energy that can do useful work
- The order created by anabolic processes is accompanied by even greater disorder in the universe that surrounds them

- Adenonsine Triphosphate (ATP) is the primary source of energy in living cells
- Phosphorylation is the process of attaching a phosphate group to an organic molecule such as ADP (the product through hydrolysis of the terminal phosphate of ATP) which allows for the molecule to become more reactive
- Redox reaction is the coupled reaction of oxidation (losing electrons) and reduction (gaining electrons, the oxidizing agent)
- When electrons transfer through a series of increasingly stronger electron carriers (called a coupled redox equation), more free energy is released in each step
- Partial transfer of electrons is when electrons of a covalent bond move closer to a more electronegative atom (shifts in electron positions)

- Enzymes (protein catalysts) will be effective the reactant molecules are facing each other in the right orientation, and collide with enough force to break molecular bonds
- Enzymes cannot change an endergonic reaction into a exergonic reaction, it can only decrease the activation energy required
- Substrate: the reactant that an enzyme acts on when it catalyzes a chemical reaction, it binds to a specific site on the enzyme
- Competitive (try and take over the active site) and Noncompetitive inhibitors (changes the shape of the enzyme so it does not fit into the active site) both prevent enzyme activity; it can either be a poison or a enzyme activity regulator
- Allosteric regulation involves allosteric sites that bind substances that inhibit or stimulate enzyme activity and alleosteric inhibitors which maintain inactive forms of enzymes

No comments:

Post a Comment