Presentation on theme: "2.4 Chemical Reactions Please spend the first 15 minutes of class working on your INB (pg. 3-17): –At least 4-6 Cornell questions per section –Answer ALL."— Presentation transcript:
2.4 Chemical Reactions Please spend the first 15 minutes of class working on your INB (pg. 3-17): –At least 4-6 Cornell questions per section –Answer ALL EQs –Complete all “Thinking Maps” You have an open note quiz tomorrow!!!! Make sure notebooks are up to date and complete. Notebook checks start Wednesday!!!!!
2.4 Chemical Reactions Sponge: Set up Cornell Notes on pg. 17 2.5 Enzymes Essential Question: How does a catalyst affect the activation energy of a chemical reaction? 2.5 Enzymes How does a catalyst affect the activation energy of a chemical reaction?
2.5 Enzymes KEY CONCEPT Enzymes are catalysts for chemical reactions in living things.
2.5 Enzymes Who would win this race? Why? Finish Line Team #1 Team #2
2.5 Enzymes Catalysts are substances that speed up chemical reactions. –decreases or lower activation energy –Therefore, increasing the reaction rate
2.5 Enzymes Pg. 16 –Split in ½ Enzymes (2 videos) Catalysts (1 video) 5 bullets 7 bullets
2.5 Enzymes Activation energy Without a catalyst
2.5 Enzymes Activation energy With a catalyst the reaction starts faster!!!!!!
2.5 Enzymes Activation energy without a catalyst Activation energy with a catalyst Draw this picture on the bottom ½ of pg. 16 to show how catalysts speed up chemical reactions
2.5 Enzymes How does a catalyst affect the activation energy of a chemical reaction?
2.5 Enzymes Answer Decreases the activation energy needed to start a chemical reaction AND also increases the rate of the chemical reaction.
2.5 Enzymes –An enzyme’s function depends on its structure (shape) –Changes in temperature and pH can affect the shape and function, or activity of an enzyme –If the enzyme shape changes it loses its ability to function
2.5 Enzymes Why is having a high fever a problem? –Enzymes work best in a small temperature range around the organism’s body temperature –Changes in temperature affect the shape and function of an enzyme
2.5 Enzymes How might putting ice on a snake bite slow down the destructive enzymes in the snake venom? –Changes in temperature affect the shape and function of an enzyme!!!!! –By putting ice on a snake bite, until help arrives, you may slow down the enzymes in the snake venom from doing too much damage to your cells
2.5 Enzymes An enzyme’s structure allows only certain reactants to bind to the enzyme. –Substrates- specific reactants that enzymes act on –Bind at active sites substrates (reactants) enzyme Substrates bind to an enzyme at certain places called active sites. Ex: Amylase- ONLY breaks down starch Starch is the substrate for amylase Ex: Lactase ONLY breaks down lactose Lactose is the substrate for Lactase
2.5 Enzymes The lock-and-key model helps illustrate how enzymes function. –If an enzymes structure (shape) changes, it may not work at all 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.
2.5 Enzymes 1.The maltase enzyme is perfectly shaped to accept a maltose molecule 2.The maltose binds to the enzyme at the activation point 3.2 glucose molecules are released 1.The lactase enzyme accepts a lactose molecule 2.The lactose binds to the enzyme at the activation point 3.Glucose molecules are released 4.If a person is lactose intolerant, the body cannot digest food or drinks with lactose