Enzymes are a Special Type of Protein Enzymes are a type of catalyst, which is a substance that speeds up the rate of a chemical reaction. Enzymes are made of proteins. Enzymes lower the energy needed to start a chemical reaction, and therefore, speed up the reaction’s rate.

Enzymes have a specific shape that matches the shape of the chemical substrate to help move the reaction along. The substrate is the reactant that the enzyme acts upon. Enzyme Unchanged Enzyme

Animation of sucrose hydrolysis Basic Enzyme animation

Certain factors can affect enzyme activity (and therefore, the reaction rate.) Temperature Changes: - A decrease in temperature can slow down the enzyme activity (which slows the reaction rate.) denaturing animation - An increase in temperature can increase the reaction until the enzyme changes shape too much and can’t change back, known as denaturing.

Graph of Effect of Temperature on Enzyme Activity

pH changes can also slow the rate of enzyme activity. (draw graph here.)

Example of a chemical reaction: The enzyme lactase helps to fit the lactose reactant with water to break it down into smaller sugar molecules (glucose and galactose.) The lactose is the substrate, which is the molecule that an enzyme acts upon.

Double Sugars and their Monomers Maltose (malt sugar) is made of 2 glucoses Sucrose (table sugar) is made of 1 glucose and 1 fructose Lactose (milk sugar) is made of 1 glucose and 1 galactose All if these sugars have the same chemical formula, but their structures are slightly different from each other (they are isomers!)

Enzymes have a specific shape that matches the shape of the chemical substrate to help move the reaction along. Lactose glucose and galactose Enzyme Unchanged Enzyme