Energy and Enzymes

When one or more substances change to create one or more different substances. Old bonds are broken and new bonds are formed.

Activation Energy : an amount of energy required to get a reaction started. Often, the amount of energy needed to start a reaction is very high and the reaction itself takes a long time. takes a lot of energy to break bonds and the molecules have to come together in the right way ANIMATION: Why EnzymesWhy Enzymes

Catalyst: 1. Speeds up a reaction by lowering the activation energy 2. Not consumed by the reaction

ENZYMES are catalysts in living things 1. protein or RNA molecule (organic contains C) 2. Speeds up chemical reactions 3. Not consumed by the reaction Most reactions are slow or require more energy than can be produced inside the body. A catalyst is essential for metabolism to work.

Enzymes fit (like a lock and key) with a substrate. Substrates are the reactants of a chemical reaction. An enzyme is shaped very specifically to react with only its substrate. ANIMATION: Specificness

1. Enzyme binds to substrate 2. Enzyme/Substrate complex forms The enzyme “hugs” the substrates 3. New Product(s) form and are released *** What do you notice about the enzyme to the right??? It is NOT CHANGED! Animation: Reusing EnzymesReusing Enzymes LOCK and KEY example which is enzyme and which substrate?

Enzymes require specific environments. (THINK HOMEOSTASIS!!) Temperature pH Salts If the enzymes environment changes – then the shape changes (DENATURES) which results in NO REACTION! Substrate no longer fits. cannot react with its other reactants the reaction stops. Animation: DenaturingDenaturing Milk/Egg Demo In Homeostasis Lost Homeostasis

Letters = reactants and products Numbers = enzymes A  B  C SO what does this mean…”If an enzyme is missing or not functioning properly, then homeostasis is lost.” Examples: 1. no vital product made (C) ex) insulin 2. accumulation of a toxin (B) ex) PKU disease 12