6.2 Enzymes and Chemical Reactions pages

Review Book for 6.1 & 6.2 Take a piece of construction paper and fold it in half. Then take 3 pieces of colored paper and fold them in half. Place paper in cover & staple folded side to create a book. Write the title on the cover with your name.

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Chemical reactions take place all the time. Chemical reactions reorganize atoms into different ones by breaking and forming chemical bonds. Enzymes are biological catalysts which speed up a chemical reaction.

Reactants are the starting materials. The newly formed substances are called products, which are different from the reactants. Reactants on the left, Products on right. For example: 6CO 2 +6H 2 O+light energy  C 6 H 12 O 6 + 6O 2 Reactants Products

The key to starting a chemical reaction is energy. Activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

Enzymes in Chemical Reactions Sometimes, the energy required for a reaction to take place is too high. The reaction can’t take place unless additional substances are present to reduce the activation energy. These substance are known as enzymes, which serve as catalysts.

Catalysts are substances that speed up chemical reactions by decreasing activation energy. A catalyst lowers activation energy Enzymes are catalysts Most reactions would occur too slowly without the help of enzymes, which speed up chemical reactions.

Enzymes speed up a chemical reaction by lowering the activation energy of a reaction.

Characteristics of Enzymes 1.Enzymes are proteins 2. Enzymes are reusable! 3. Enzymes denature in high temperatures * denature = destroyed, broken apart, digested * denaturation is not reversible 4.All enzymes end with ‘-ase’. Ex) Lactase breaks down Lactose (milk sugar)

Factors that Affect Enzyme Activity 1.TEMPERATURE -Too warm, enzyme will denature. -Too cold, enzymatic activity will slow down. 2. pH - a change in pH can change the shape of the enzyme so that substrates can’t fit into active site.

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. 1.Substrates are brought together. 2.They attach to the active site of enzymes. 3.Bonds are then made or broken. 4.Product is released. The lock-and-key model helps illustrate how enzymes function. Enzymes are SPECIFIC (they break down only one thing) *They will only FIT with certain substrates*

‘Lock and Key Model’ – says there is a perfect fit between active site and substrate

VOCABULARY Enzymes – biological catalysts or special proteins that speed up chemical reactions Catalysts – substances that speed up chemical reactions) Substrates – materials that bind to the enzyme Active Site - Location on the enzyme where the substrate binds

How an enzyme affects a chemical reaction:

3. What is the optimum temperature for the enzyme? 4. At what temperature is the enzyme completely denatured? 1. What is this graph showing? 2. What is the independent variable? 62°C 40°C temperature and enzyme activity temperature

If you did not complete lab. Do that FIRST! Enzyme worksheet Pg and 4 Pg : 1,2,4,7,14-23