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CHEMICAL REACTIONS. Process which changes one set of chemicals into another set of chemicals. Ex. Combining Iron (Fe) and Oxygen (O) to form Rust . Reactants - elements or compounds that enter into a chemical reaction Products - elements or compounds made by a chemical reaction.
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CHEMICAL REACTIONS • Process which changes one set of chemicals into another set of chemicals. • Ex. Combining Iron (Fe) and Oxygen (O) to form Rust. • Reactants - elements or compounds that enter into a chemical reaction • Products - elements or compounds made by a chemical reaction. • Bonds are broken in reactants and formed in products.
CHEMICAL REACTIONS ALWAYS INVOLVE CHANGES IN ENERGY • REACTIONS THAT RELEASE ENERGY SOMETIMES HAPPEN SPONTANEOUSLY • REACTIONS THAT ABSORBENERGY MUST HAVE A SOURCE OF ENERGY • THE ENERGY NEEDED TO START A REACTION IS CALLED ACTIVATION ENERGY.
CATALYSTS • SUBSTANCES THAT SPEED UP RATE OF REACTION. • WORK BY LOWERING THE ACTIVATION ENERGY. • ENZYMES ARE PROTEINS THAT SPEED UP CHEMICAL REACTIONS IN CELLS. CAUSES THE REACTION TO TAKE PLACE BY LOWERING THE ACTIVATION ENERGY NEEDED. • EX. CO2 + H2O H2CO3 • Carbonic anhydrase
SPEED OF REACTIONS • LEFT ALONE MANY BIOLOGICAL REACTIONS WOULD HAPPEN TOO SLOWLY. • Example of an enzyme • CARBONIC ANHYDRASE CAUSES THE CHANGE INTO CARBONIC ACID TO HAPPEN QUICKLY. • ENZYMES ARE SPECIFIC AND USUALLY ONLY CATALYZE ONE REACTION.
ENZYME ACTION • REACTANTS IN CHEMICAL REACTIONS MUST HIT WITH ENOUGH FORCE TO BREAK OLD BONDS AND FORM NEW ONES • ENZYMES PROVIDE THE PLACE WHERE REACTANTS ARE BROUGHT TOGETHER REDUCING THE ENERGY NEEDED FOR THE REACTION TO OCCUR.
ENZYME SHAPE • SUBSTRATES - THE REACTANTS OF ENZYME CATALYZED REACTIONS • EACH PROTEIN HAS A SPECIFIC SHAPE. • ACTIVE SITE ON THE PROTEIN HAS A COMPLIMENTARY SHAPE TO THE SUBSTRATE. • ENZYME AND PROTEIN FIT TOGETHER LIKE PUZZLE PIECES. • SEE PG. 52 • ENZYMES ARE REUSABLE.
ENZYME ACTIVITY • AFFECTED BY Ph • Many biological enzymes function best at a pH of 7 • Most biological enzymes function best at normal human body temp. • Few enzymes function well at high temperature
Activation Energy • What significance do these energy changes have to do with living things? In order to stay alive, organisms need to carry out reactions that require energy.
Regulation of Enzyme Activity • Because they are catalysts for reactions, enzymes can be affected by any variable that influences a chemical reaction. • Many enzymes are affected by temp, pH, etc.
http://www.youtube.com/watch?v=V4OPO6JQLOE&list=FLos62yqwp6aQmbJI7D_f7CA&index=46&feature=plpp_videohttp://www.youtube.com/watch?v=V4OPO6JQLOE&list=FLos62yqwp6aQmbJI7D_f7CA&index=46&feature=plpp_video • Difference between no enzyme and enzyme in solution Awesome Animation • http://www.whfreeman.com/catalog/static/whf/thelifewire6e/con_index.htm?99xex • How enzymes work in the body! • http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter3/enzyme_action_and_the_hydrolysis_of_sucrose.html