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It’s your turn to make dessert!

It’s your turn to make dessert!. Your Aunt Sally used to make Jell-O with pineapple – do you use canned pineapple juice or fresh pineapple juice?. Chemical Reactions & Enzymes. Chemical Reactions. A change of one set of chemicals into another Can be slow or fast

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It’s your turn to make dessert!

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  1. It’s your turn to make dessert! • Your Aunt Sally used to make Jell-O with pineapple – do you use canned pineapple juice or fresh pineapple juice?

  2. Chemical Reactions & Enzymes

  3. Chemical Reactions • A change of one set of chemicals into another • Can be slow or fast • Require collisions between molecules • Involves changes in chemical bonds

  4. Chemical Reactions • Reactants: elements or compounds that enter into a chemical reaction • Bonds of reactants are broken in a chemical reaction! • Products: elements or compounds that are produced in a chemical reaction • Bonds of products are formed in a chemical reaction! What are the reactants in this reaction? The products?

  5. Chemical reactions involve changes in chemical bonds! Whenever a reaction occurs that rearranges the atoms of molecules, bonds in the reactants must be broken & new bonds in the products must be formed.

  6. Chemical reactions involve energy! • Breaking & forming chemical bonds requires energy release or absorption. • Reactions that release energy can occur spontaneously (but not all do)! • Energy is released as heat. • Reactions that absorb energy will not occur without an energy source!

  7. The chemical reaction of photosynthesis requires energy from the sun!

  8. Energy-Releasing Reaction Energy-Absorbing Reaction Activation energy Products Activation energy Reactants Reactants Products Activation Energy Video Activation Energy • The energy needed to get a reaction started • Some chemical reactions are very slow or require lots of energy, so they cannot occur on their own!

  9. Catalysts • Catalysts are proteins that speed up the rate of a chemical reaction by lowering the activation energy of the reaction.

  10. Enzymes are catalysts! • An enzyme is a protein that acts as a biological catalyst! • Enzymes speed up reactions that take place in your body!

  11. Enzymes • Enzymes provide a site (called the active site) where reactants can be brought together to react. • This decreases the activation energy! • Enzymes can be reused, but they are specific! • They will only fit with 1 set of reactants!

  12. The enzyme-substrate relationship is like a lock & key! Only the correctly shaped key will open the lock…

  13. Why won’t Jell-O set with fresh pineapple? • Fresh pineapples naturally have A LOT of bromelin! • Bromelin is an enzyme that destroys proteins! • Canned pineapples don’t have any bromelin, because they have been pasteurized. • This means that they’ve been put through a lot of heat, & the heat destroys enzymes. • Jell-O is held together with a protein called collagen. What would happen if collagen came into contact with bromelin?!

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