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Chemical reactions.  Add the baking soda to one corner of the bag and add vinegar to the other end of the bag. MAKE SURE THEY ARE SEPARATE.  Mix the.

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Presentation on theme: "Chemical reactions.  Add the baking soda to one corner of the bag and add vinegar to the other end of the bag. MAKE SURE THEY ARE SEPARATE.  Mix the."— Presentation transcript:

1 Chemical reactions

2  Add the baking soda to one corner of the bag and add vinegar to the other end of the bag. MAKE SURE THEY ARE SEPARATE.  Mix the substances and watch the reaction

3  what physical changes did you observe?  Sodium bicarbonate + vinegar  water + carbon dioxide  Reactants? Enter into a chemical reaction  products? What are formed from the chemical reaction 

4  Chemical change always involves change in the bonds that join the atoms.  RIvc2E RIvc2E  In order for a chemical reaction to happen, there needs to be enough energy to break existing bonds so new bonds can be formed.

5 Activation energy  The energy needed to get a reaction started is activation energy.  Chemical reactions need energy to react.  Red rover Energy releasing Like burning a match!

6 Label the graph!! ? ? ? ? ?

7 Enzymes  Chemical reactions are made possible in our bodies but the activation energy is so high, they need the help of enzymes  Enzymes- Proteins that speed up a chemical reaction by lowering the activation energy.  Catalyst- An inorganic enzyme. (can work in more extreme conditions)

8 Enzymes Enzymes are protein molecules, and so are made up of amino acids. Most enzymes contain between 100 and 1,000 amino acids. These amino acids are joined together in a long chain, which is folded to produce a unique 3D structure. Enzymes work by binding to a specific component due to its shape.

9 Enzymes are very specific about which reactions they catalyze. Only molecules with exactly the right shape will bind to the enzyme and react. These are the reactant, or substrate, molecules. The part of the enzyme to which the reactant binds is called the active site. This is a very specific shape and the most important part of the enzyme.

10 What happens at the active site? In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site. The enzyme is the lock, and the reactant is the key. enzyme reactant + enzyme-reactant complex ↔ products enzyme + ↔ + ↔↔ +

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12  Enzymes are NOT used up in this process, after they combine with the necessary substrate ( reactant ) in the reaction.  When the enzyme and substrate combine, the substrate is changed to a different chemical called the product.  when the substrate and the active site on an enzyme combine, a product is created.  The product is then released so a new substrate can bind.

13 Induced Fit Model  Enzyme changes shape to fit the substrate.  The induced fit model has been compared to a hand-in-glove model, wherein it may be difficult to insert the first finger into the proper place, but once done, the other fingers go in easily because the glove is now properly aligned.  ine_content/media/gob_now/dswmedia/se ager/CI_Seager_22_2.html ine_content/media/gob_now/dswmedia/se ager/CI_Seager_22_2.html

14 All enzymes work best at only one particular temperature and pH: this is called the optimum. Factors that affect the rate of a reaction include: substrate concentration temperature pH enzyme concentration surface area pressure. Different enzymes have different optimum temperatures and pH values.

15 If the temperature and pH changes sufficiently beyond an enzyme’s optimum, the shape of the enzyme irreversibly changes. heat pH This affects the shape of the active site and means that the enzyme will no longer work. When this happens the enzyme is denatured. normal denatured

16 Review  What is an enzyme?  What are the 2 common ways enzymes are denatured?  An enzyme is similar to a __________ but it is biological.


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