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CHEMICAL REACTIONS & ENZYMES. CHAPTER 2 SECTION 4 SC-B-2.8-EXPLAIN THE FACTORS THAT AFFECT THE RATES OF BIOCHEMICAL REACTIONS (INCLUDING pH, TEMPERATURE, & THE ROLE OF ENZYMES AS CATALYSTS). WHY ARE ENZYMES IMPORTANT TO LIVING THINGS?. ESSENTIAL QUESTION.
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CHEMICAL REACTIONS & ENZYMES CHAPTER 2 SECTION 4 SC-B-2.8-EXPLAIN THE FACTORS THAT AFFECT THE RATES OF BIOCHEMICAL REACTIONS (INCLUDING pH, TEMPERATURE, & THE ROLE OF ENZYMES AS CATALYSTS).
WHY ARE ENZYMES IMPORTANT TO LIVING THINGS? ESSENTIAL QUESTION
A chemical reaction is a process that changes one set of chemicals into another set of chemicals.
Reactants Products • elements or cpds that enter into a chemical reaction • elements or cpds that are produced in a chemical reaction Chemical Reactions
The chemical bonds of the reactants are broken & the chemical bonds of the products are formed. Chemical Reactions
Some chemical reactions in living things are reversible. • example: Reversible Reactions
Whenever chemical bonds are formed or broken energy is released or absorbed. • Chemical reactions that release energy often occur spontaneously. • Chemical reactions that absorb energy will not occur without a source of energy. ENERGY IN REACTIONS
Exergonic reactions (release energy) in form of: • heat • light • sound
In living organisms exergonic reactions often coupled with endergonic reactions
is the energy necessary to get the reaction started • required whether reaction is exergonic or endergonic Activation Energy
Enzymes are biological catalysts • very specific • substance(s) it reacts with called a substrate • speed up chemical reactions • lower activation energy • without enzymes chemical reactions would take so long to occur there would be no life. • name often tells you what it acts on • name ends in -ase Enzymes
Active Site: location on enzyme molecule where substrate fits in (like key into a lock) Enzymes: Active Site
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.ryancshaw.com/Files/micro/Animations/Enzyme-Substrate/micro_enzyme-substrate.swf
pH • enzymes in stomach work @ pH 2, stop working when get to small intestine where pH is higher • temperature • in humans: enzymes work best @ 37 ◦C • cell regulators • most enzymes not active 24/7 but have a “switch” cells use as needed Factors that Affect Enzyme Activity