2.  Energy – the capacity to perform work  Its types: › Kinetic energy › Potential energy  A form of kinetic energy is heat.  A form of potential energy is chemical energy (energy of molecules)

3.  Chemical reactions can store or release chemical energy.  If a reaction is endergonic – energy is taken in by the reactants to form the products (like dehydration synthesis or photosynthesis)  If a reaction is exergonic – energy is released by the reactants to form the products (like cellular respiration)  Frequently, exergonic reactions fuel endergonic reactions – energy coupling

5.  ATP: A modified nucleotide molecule that powers all cellular work directly.  Its structure: adenine, ribose and three phosphates are combined by dehydration synthesis

6.  ATP molecules release phosphate groups to various other molecules. These molecules take in the phosphate by phosphorylation and get excess energy to perform various processes.  When ATP releases a phosphate + energy it produces ADP (adenosine diphosphate)  ADP can turn back to ATP by taking in a phosphate and energy by phosphorylation

7.  http://www.biologyinmotion.com/atp/index.html http://www.biologyinmotion.com/atp/index.html  http://student.ccbcmd.edu/biotutorials/energy/atpan.html http://student.ccbcmd.edu/biotutorials/energy/atpan.html

8.  The energy from ATP can be used for the following processes: › Chemical work (forming products from reactants) › Mechanical work (contracting muscle) › Transport work (moving substances into or out of the cell)

9.  Enzymes are proteins that act as biological catalysts in living organisms.  They speed up chemical reactions by lowering the activation energy of the reaction.  http://www.stolaf.edu/people/giannini/flashanimat/enzymes/transition%20state.s wf http://www.stolaf.edu/people/giannini/flashanimat/enzymes/transition%20state.s wf

10.  Enzymes have a specific section called the active site that is able to bind with the reactants ( substrates ) of a chemical reaction  Once the substrates bind to the active site, the active site changes shape and pulls the reactants together. As a result, the reaction occurs faster and more efficiently.  The model that describes that enzymes change shape when bind with the substrate is called the induced fit model

12.  Animations: http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation __how_enzymes_work.htmlhttp://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation __how_enzymes_work.html  http://www.lpscience.fatcow.com/jwanamaker/animations/ Enzyme%20activity.html http://www.lpscience.fatcow.com/jwanamaker/animations/ Enzyme%20activity.html  http://www.northland.cc.mn.us/biology/biology1111/animati ons/enzyme.swf http://www.northland.cc.mn.us/biology/biology1111/animati ons/enzyme.swf

13.  Three important special characteristics of enzymes: › They are specific › They are efficient › They are sensitive

14.  Many enzyme do not function without an additional group attached to them. This additional group is called a cofactor.

15.  Some substances can stop enzymes from functioning by attaching themselves to the active site of the enzyme. These are called inhibitors.  Many inhibitors are used as poisons or drugs.