Metabolism Metabolism - Cellular chemical processes Catabolism – breaking down larger molecules into smaller ones Anabolism – building up larger molecules from smaller ones

An example of catabolism is digesting proteins. An example of anabolism in building muscles. BOTH REQUIRE A GREAT DEAL OF ENERGY!!!!!!!!

Energy needed for a catabolic or anabolic reaction is called activation energy. Enzymes are proteins. They speed up a chemical reactions AND lower the activation energy. It is much much much easier for these reactions to occur in your body with enzymes.

Just like it is much easier for you to push a wheel barrow up a short hill than a tall one.

An enzyme is a protein that changes the rate, or speed, of a chemical reaction. Enzymes are involved in almost ALL metabolic processes. They speed up digestion of food. The activities of enzymes depend on temperature, ionic conditions, and the pH of the surrounding area. A substrate fits to the active site on an enzyme like a puzzle piece. This is where the reaction will occur. Look at pg 162 in the textbook.

Enzymes are the biological substance (proteins) that act as catalysts and help complex reactions occur everywhere in life.

W – substrate X – enzyme Y – enzyme-substrate complex Z - product

What kinds of things effect enzyme function? Temperature – enzymes work best at a ideal temperature any change higher or lower will make the enzyme slower

Enzyme concentration – the more enzymes present, the more work they can do, so the more chemical reactions can occur. How many more toothpicks can be broken by two people than one?

A change in pH can denature an enzyme Denatured enzyme – when the shape of a enzyme is changed, it will often not work as well. What happens when you try to break toothpicks with your fingers crossed? What about if you bent the shaft on a screw diver?

Enzyme inhibition – sometimes other molecules will interfere with the action of an enzyme on a molecule What happened when pipe cleaners were added to the toothpicks?

Substrate concentration – enzymes have to “find” their substrates. The more there are, the easier they are to find. What happened when the toothpicks were more spread out? On an Easter egg hunt does it get easier or harder to find eggs as other people find them?

There are two major enzyme systems in the human body. One is digestive and the other is metabolic. The digestive enzymes help break down all of the food that we eat so that it can be absorbed by the body. The metabolic enzymes help to run all of the systems of the body from respiratory system to the nervous system. The seven categories of food (digestive) enzymes and their activities are: Cellulase: breaks down fibers. (cellulose) Lactase: breaks down dairy products. (lactose) Maltase: breaks down grains. (maltose) Sucrase: breaks down sugars. (sucrose) Notice the suffix changes from “ose” to “ase” as the enzyme breaks it down.