À Process That Changes One Set of Chemicals Into Another Set of Chemicals

2.4 Chemical Reactions

 Process that changes one set of chemicals into another set of chemicals  Always involve changes in the chemical bonds that join atoms in compounds ______I. Writing Equations A. REACTANTS 1. Compounds that ______a chemical reaction B. PRODUCTS 1. Compounds ______by a chemical reaction

II. Energy in Reactions A. Bonds 1. storage place of energy in molecules / compounds a. Break a bond à b. Make a bond à B. EXERGONIC (E exiting) 1. Chemical reactions that ______2. Often ______a. occur on their own b. But often need a “push” to get started C. ENDERGONIC (E needing) 1. Chemical reactions that ______2. Need energy input to occur

D. ACTIVATION ENERGY à ______1. The “push” E. Reaction in Living Things 1. All living things carry out ______reactions 2. But 1st they need to get the energy from somewhere! a. Exergonic sources of energy i. ______ii. ______iii. ______3. Problem: These reactions all ______in order to keep up with the speed of life! 4. Solution: ______

III. ENZYMES A. Catalyst 1. Definition  ______2. How?  Lowers the reaction’s ______3. Chemical reactions would occur WAY too SLOW in the body without these biologic catalysts! B. Major Functions 1. Living cells use enzymes to ______virtually every important chemical reaction that takes place inside cells 2. They are ______3. ______the activation energy required and allow reactions to happen at the normal temperature of cells. C. Characteristics of Enzymes 1. ______à only works on one particular reaction 2. ______à over and over again for that reaction 3. ______ after their substrate a. A substrate is the reactant that the enzyme helps b. Enzyme name ends in –ASE 4. Enzyme & Substrate bind in a “lock-&-key” specificity at the enzyme’s ______5. ______are non-protein helper molecules that may assist enzymes do their job.

D. Enzyme Example 1. Cells release carbon dioxide into the blood a. Carbon dioxide reacts with water to become ______which is soluble in blood b. When carbonic acid gets to ______, converts back to carbon dioxide

CO2 + H20 à H2CO3

2. + - CO2 + H20 ßà H2CO3 ßà H + HCO3 a. This reaction “buffers” the blood

3. Left by itself, reaction would not take place fast enough to remove carbon dioxide from our body a. ______4. Enzyme = ______a. Speeds up reaction ______5. Enzyme Action

E. Enzyme action 1. very sensitive to ______2. 3. ______a. Human body = 37C 4. ______= how many are there? 5. ______= other substances can interfere 6. ______= how long do the compounds get to interact?