Enzymes Our guiding question How do chemical bonds

Enzymes Our guiding question: • How do chemical bonds get made and broken in a cell?

Questions-notes on enzymes List the 4 properties of enzymes based on your answers to the following questions: 1. What is the difference in a reaction with or without an enzyme? 2. Can an enzyme help only one reaction? Explain why-why not. 3. Can an enzyme be used repeatedly in a reaction? Explain why-why not. 4. Explain what happens to an enzyme when it is heated or placed in an extreme p. H (p. H is a measure of acid or alkali)?

Enzymes: An animated tutorial Follow the interactive animations at the following website to answer the questions about enzyme properties. Enzyme tutorial

4 Properties of Enzymes 1) Enzymes speed up the rate of chemical reactions 2) Enzymes are specific to one type of chemical reaction The ACTIVE SITE of the enzyme “fits” only the chemical(s) that the enzyme works on (substrate).

3) Enzymes are NOT changed or used up in the chemical reaction Only small amounts are needed since they are recycled and reused 4) Enzyme shape is changed (stop working because of shape change) when they are heated or placed in acid (denatured).

Protein Links Proteins are the body's worker molecules http: //publications. nigms. nih. gov/structlife/chapter 1. html Explore some proteins (and other molecules) in 3 D http: //www. umass. edu/molvis/bme 3 d/materials/explore. html Protein and Enzyme Animations 1. Animation of what happens to the protein in egg white when it is cooked http: //www. sumanasinc. com/webcontent/anisamples/nonmajorsbiology/proteinstructure. html 2. Animation of the role of enzymes along a biochemical pathway. http: //highered. mcgraw-hill. com/sites/0072437316/student_view 0/chapter 8/animations. html# click on “A Biochemical Pathway” 3. Another animation of enzyme action http: //www. hillstrath. on. ca/moffatt/bio 3 a/digestive/enzanim. htm 4. A good description [with animations] of the properties of enzymes. http: //www. lpscience. fatcow. com/jwanamaker/animations/Enzyme%20 activity. html An explanation of primary, secondary, tertiary, and quaternary structure in proteins http: //www. stolaf. edu/people/giannini/flashanimat/proteins/protein structure. swf

Now……. . What is a PROTEIN?

2 Types of Proteins 1) Structural – proteins that form physical parts: Examples – -keratin (hair and nails) -actin (muscle) -microtubules (cell membrane skeletons). -Collagen (skin)

2) Functional – Proteins that have an activity: Examples-Signaling – e. g. some hormones are proteins -Defense – antibodies that recognize foreign invaders -Transport – Carrier proteins (e. g. hemoglobin carries O 2) -Enzymes – used for chemical reactions (e. g. lactase hydrolyses lactose)

Protein Shape Determines its Function Example - Fibrous proteins are long and thin, and are used for structure [e. g. collagen] Example - Enzymes also have a specific shape to recognize a specific substrate [vocabulary] [e. g. lactase]