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Chemical Reactions and Enzymes.  Are processes that change or transform, one set of chemicals into another.  Drive all the activities associated with.

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Presentation on theme: "Chemical Reactions and Enzymes.  Are processes that change or transform, one set of chemicals into another.  Drive all the activities associated with."— Presentation transcript:

1 Chemical Reactions and Enzymes

2  Are processes that change or transform, one set of chemicals into another.  Drive all the activities associated with life.

3  Involve reactants (starting materials) and products (ending materials).  The atoms of the reactants are rearranged to form the products.

4  There are two types  Endothermic ▪ Absorb energy ▪ Breakdown macromolecules  Exothermic ▪ Release energy ▪ Build macromolecules

5  Need some energy to get started  The needed energy is called activation energy. ▪ Activation energy is a chemical push  Is required for both exothermic and endothermic reactions.  Is lowered by enzymes ▪ Enzymes are biological catalysts that speed up chemical reactions, but are not used up by them.

6 Why do enzymes speed up reactions? Enzymes speed up reactions by lowering the activation energy (E a ) of a reaction. The activation energy is the energy needed to start a reaction. Different reactions have different activation energies. reaction (time) energy (kJ) E a with enzyme E a without enzyme

7  Are large folded proteins that are made of hundreds of amino acids.

8  All enzymes have active sites  Active sites ▪ Form in the protein folds. ▪ Have a complimentary substrate shape.

9  Speed up chemical reactions by binding with specific molecules.  The specific molecule is a substrate.  Promote specific chemical reactions

10 http://www.youtube.com/watch?v=V4OPO6J QLOE

11  Are affected by heat, acidity, and enzyme concentration  Enzymes function with in a certain temperature range.  Enzymes cease to function if the strength of acids in body fluids is too high or too low.  Enzyme concentration determines if a reaction occurs.

12 Enzymes and temperature

13  Work with a partner to answer questions 1-3 of Assessment 2.4 on page 53 of your Biology textbook. Write the questions and answers in your notebook. Answer the questions thoughtfully and with complete sentences.

14 Enzymes and temperature


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