1. Enzymes Chapter 2: Section 2.5 1

2. Objectives SWBAT explain the effect of a catalyst on activation energy. SWBAT describe how enzymes regulate chemical reactions and maintain homeostasis. 2

3. Vocabulary Catalyst Enzyme Substrate 3

4. Starter: How can this be possible 4

5. Catalyst A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions. – decrease activation energy – increase reaction rate (speed up reactions). 5

6. Enzymes are catalysts in living things Enzymes allow chemical reactions to occur under tightly controlled conditions. – Like inside of a cell or intercellular space. Enzymes are catalysts in living things. – Enzymes are needed for almost all processes. – Enzymes are proteins. 6

7. Detailed Definition Enzymes UC Davis Site: http://chemwiki.ucdavis.edu/Biological_Chem istry/Catalysts http://chemwiki.ucdavis.edu/Biological_Chem istry/Catalysts When we think about information and its reliability, the source is important. If you would like to read in detail about enzymes (at a college level) check out this website. 7

8. Point of Review Enzymes are proteins. Proteins are what kind of Molecule? Answer: a carbon-based molecule. Proteins are made up of what? Answer: they are made up of amino acids. Proteins are polymers of amino acids (making amino acids monomers). 8

9. Reactions with and without enzyme Substrate refers to your reactants 9

10. Reactions without Enzymes Chemical reactions in biological systems would occur very slowly if at all without enzymes. Enzymes are essential for maintaining homeostasis. – Homeostasis is the equilibrium that exists among all of the physiological processes occurring in a living organism at any given time. – When homeostasis is compromised, the organism is unwell – Ex. viruses can disrupt homeostasis. 10

11. An enzyme’s function depends on its structure. An enzyme’s structure allows only certain reactants to bind to the enzyme. –substrates –active site substrates (reactants) enzyme Substrates bind to an enzyme at certain places called active sites. 11

12. An enzyme’s function depends on its structure. The lock-and-key model helps illustrate how enzymes function. –substrates brought together –bonds in substrates weakened Substrates bind to an enzyme at certain places called active sites. The enzyme brings substrates together and weakens their bonds. The catalyzed reaction forms a product that is released from the enzyme. 12

13. Example of Enzyme and Substrate Enzyme + ReactantProduct + Enzyme Example: Starch (carbohydrate + Amylase Maltose (C 12 H 22 O 11 ) + Amylase – NOTE: The amylase, being an enzyme, is never used up. It catalyzes the reaction. In your large intestine, maltose is further broken down by amylase into glucose. – Amylase + MaltoseGlucose + Amylase. 13

14. Examples Protease + Protein Amino Acids + Protease. Lipase + Lipids Fatty Acids + Lipase Again NOTE: The enzymes are not consumed by the chemical reactions. They catalyze them! 14

15. Examples of Enzymes Tryptophan hydroxylase (an enzyme) takes tryptophan (the substrate) and facilitates the synthesis of serotonin. – Serotonin is a steroid that is a neurotransmitter (a chemical substance that transmits nerve impulses across synapses). – It is involved in mood, appetite, sleep, memory, learning and depression (upping levels tends to relieve depression). 15