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CH 2.4 Chemical Reactions & Enzymes. Everything that happens in an organism – growth…movement…reproduction… is based on chemical reactions.

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Presentation on theme: "CH 2.4 Chemical Reactions & Enzymes. Everything that happens in an organism – growth…movement…reproduction… is based on chemical reactions."— Presentation transcript:

1 CH 2.4 Chemical Reactions & Enzymes

2 Everything that happens in an organism – growth…movement…reproduction… is based on chemical reactions.

3 Chemical reactions involve changes in the chemical bonds that join atoms in compounds.

4 Breathing, for example… … pretty important thing.

5 CO 2 + H 2 O H 2 CO 3 H 2 CO 3 CO 2 + H 2 O Your cells constantly produce carbon dioxide as a normal part of their activity.

6 CO 2 + H 2 O H 2 CO 3 H 2 CO 3 CO 2 + H 2 O Your cells constantly produce carbon dioxide as a normal part of their activity. As it enters the blood, CO 2 reacts with water to form the highly soluble compound – carbonic acid.

7 CO 2 + H 2 O H 2 CO 3 H 2 CO 3 CO 2 + H 2 O Your cells constantly produce carbon dioxide as a normal part of their activity. As it enters the blood, CO 2 reacts with water to form the highly soluble compound – carbonic acid. In your lungs, this reverse reaction produces CO 2 gas – released when you exhale.

8 Energy is released or absorbed whenever chemical bonds form or are broken.

9 Because chemical reactions involve breaking & forming bonds, they involve changes in energy.

10 Reactions that release energy often occur spontaneously.

11 Reactions that absorb energy will not occur without an energy source.

12 2H 2 + O 2 2H 2 O

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14 2H 2 O2H 2 + O 2

15 To stay alive, organisms must carry out reactions that require energy. Every organism must have a source of energy to carry out chemical reactions.

16 Plants get that energy through photosynthesis.

17 Humans get that energy by eating plants and/or animals, then metabolizing (breaking down) that food via chemical reactions during digestion.

18 Activation Energy: the energy needed to start a chemical reaction.

19 Activation energy is a factor in whether the reaction releases or absorbs energy.

20 Which is which??? Energy absorbed Energy released

21 Some chemical reactions necessary for life are too slow, or have very high activation energies that make them impractical for living tissue. Catalysts speed up reactions by lowering the activation energy.

22 Enzymes are proteins that act as biological catalysts. Enzymes speed up the reactions that take place in cells.

23 CO 2 + H 2 O H 2 CO 3 …remember this reaction? Without the enzyme carbonic anhydrase to speed it up, CO 2 would build up in your bloodstream and cause severe health issues!

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25 Enzymes are affected by: pH temperature (your enzymes work best at 98.6⁰) Enzymes play essential roles in: regulation of chemical pathways making material needed by cells releasing energy transferring information


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