ENZYMES hillarybio.blogspot/2008_09_01_archive.html

1. ENZYMES http://hillarybio.blogspot.com/2008_09_01_archive.html

2. Types of Chemical Reactions in Your Body synthesis reactions • anabolic: (building/creating) • smaller molecules join to form larger molecules ex: making cell parts (growth, repair) • glucose • catabolic: (breaking down) • larger molecules broken down into smaller ones ex: polysaccharides glycogen (in animals) (in plants) starch digestion reactions monosaccharides

3. Enzymes proteins enzymesare • biological catalysts (speed up chemical reactions) • they are reusable Enzyme Structure • each enzyme has a place called the active site • substrate is the reactant that an enzyme acts on when it catalyzes a chemical reaction • the active site is the location where the substrate binds to an enzyme • enzymes are very specific for the types of substrates they attach • most will only attach to one type of molecule • a different enzyme is therefore needed for every reaction in the body • the substrate and the active site must have well-matched shapes for binding to occur

4. Enzymes Induced-Fit Model • as the substrate enters the active site, the protein changes shape to better fit the substrate • the attachment of the substrate to the active site creates the enzyme-substrate complex Lock & Key Hypothesis • each enzyme is uniquely designed to fit with its substrate (reactant in a chemical reaction) at the active site • they fit perfectly like ‘a lock & key’ anabolic reaction catabolic reaction

5. Lock & Key Hypothesis Anabolic Chemical Reaction substrate 1. substrates bind with the enzyme’s active site 4. enzyme-substrate complex forms active site 2. enzyme • product is released • enzyme detaches & is reused 3. • bonds are formed between 2 substrates • endothermic

6. Lock & Key Hypothesis Catabolic Chemical Reaction • products are released • enzyme detaches & is reused 4. 1. substrate binds with enzyme’s active site • bonds are broken • exothermic 3. 2. • enzyme-substrate complex forms • helps break bond

7. Lock & Key Hypothesis An Example Products

8. Denaturation of Proteins + heat denaturation: • when proteins lose their specific 3D shape • washing a pure wool (protein) sweater in hot water → shrinks • egg white & yolk solidify when heated • denatured enzymes lose their functionality • substrate no longer fits the enzyme’s active site • chemical reaction won’t be catalyzed denaturation can be caused by: • very hot temperatures • strong acids (low pH) • strong bases (high pH) ex. Note: Each enzyme has an ideal temperature & pH at which it works best.

9. Importance of Enzymes Proteins make up about 15% of the mass of the average person. Protein molecules are essential to us in many different ways. A lot of our body is made from protein molecules. Muscle, cartilage, ligaments, skin and hair are mostly made of protein materials. Larger proteins also hold us together. Smaller protein molecules play a vital role in keeping our body working properly. Haemoglobin, hormones (ex. insulin, antibodies, and enzymes are all examples of smaller proteins. Both vegetarians and meat eaters must have protein in their diet. The protein in the food we eat is our main source of the chemical building blocks we need to build our own protein molecules.

10. Activity Synthesizing a Paper-Clip Polymer with a Paper Enzyme

11. Homework