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.
Enzymes are biological molecules that catalyse (speed up) chemical reactions. Enzymes are specificâthey will only work on particular molecules. For example, the enzyme sucrase will only bind with and break bonds in sucrose, not any other type of sugar.nother characteristic of enzymes is that they can be re-used over and over again. A single enzyme will typically catalyse around 10,000 chemical reactions per second. This means that only a tiny amount of enzyme is needed to have a huge effect on a reaction.