Pitch: the use of notes in voice range. Speak in a voice range that is comfortable and move up or down Pause: Give you time to catch your breath and the audience time to collect your ideas. Articulation and Pronunciation: Articulation is the art of expressing words distinctly. Pronunciation is the ability to say words correctly. Length: Length of your presentation is crucial.
Enzyme. Photo by: fotohunter. An enzyme is a biological catalyst. A catalyst is a chemical compound that speeds up the rate of some chemical reaction. When that chemical reaction occurs in a living organism, the catalyst is known as an enzyme.hemical reaction: Any change in which at least one new substance is formed. Lock-and-key model: One of the ways in which enzymes bring about chemical reactions. Product: A compound that is formed as the result of a chemical reaction.
There are hundreds or millions of copies of each different type of enzyme, depending on how important a reaction is to a cell and how often the reaction is needed. These enzymes do everything from breaking glucose down for energy to building cell walls, constructing new enzymes and allowing the cell to reproduce.