We've been talking about various biological molecules and that they are needed for reactions in the body (DNA, Protein synthesis, Cellular respiration etc.) and how molecules can change. You should know that it doesn't happen on its own. If you leave a blob of protein in a petri dish will it just break down to the amino acids? No. What will break down proteins? Enzymes! Enzymes are the biological substance (proteins) that act as CATALYSTS and help complex reactions occur everywhere in life.
A catalyst is a substance that increases the rate of a chemical reaction by reducing the amount of energy needed to start that reaction. This is called lowering the activation energy. ACTIVATION ENERGY can be thought of as a hill that must be gotten over. When a catalyst acts, it lowers the energy required to get over the HILL and the reaction can proceed. An enzyme is an organic catalyst meaning that it is a protein that catalyzes reactions in living organisms. Most reactions in the body require enzymes
LOCKS AND KEYS
A door that is locked needs a key that is just the right shape to fit in that lock. Otherwise you're stuck in the cold. Enzymes work in a similar way. Enzymes complete very specific jobs and do nothing else. They are very specific locks and the compounds they work with are the special keys.
Here's the deal... There are four steps in the process of an enzyme working.
(1) An enzyme and a SUBSTRATE are in the same area. The substrate is the biological molecule that the enzyme will work on.
(2) The enzyme grabs onto the substrate with a special area called the ACTIVE SITE. The active site is a specially shaped area of the enzyme that fits around the substrate. The active site is the keyhole of the lock.
(3) A process called CATALYSIS happens. Catalysis is when the substrate is changed. It could be broken down or combined with another molecule to make something new.
(4) The enzyme lets go. Big idea - When the enzyme lets go, it...