Summary 5.5

=Enzymes are proteins that speed up specific reactions in cells=

*Key terms
activation energy: the 'start-up' energy that activates the reactants and triggers a chemical raaction.
catalysts: compounds that speed up chemical reactions
enzymes: the main catalysts of chemical reactions in organisms that are spcialized proteins
substrate: a specific reactant acted upon by and enzyme
active site: a particular region of enzyme where substrate fits into

*Enzymes and Activation Energy

- Reactions all need activation energy to react and produce a product.
-Ways to provide activation energy: -heat up the mixture of molecules.
-cellular reactions depend on the catalysts.
-specialized proteins called enzymes.
-enzymes help cells to react in its normal tempertaure
-not providing activation energy
-lowers the energy requirement barrier

*How Enzymes Work
-Enzyme fits the shape of only particular reactant molecules
-The fit between enzyme and substrate is snug
- tighter grip may also bend the substrate, weakening its bonds
- lower activation energy by accepting two reactant molecules
-temperature, pH, etc affects enzyme works.

*Concept Check 5.5
1. Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?
- Activation energy is the energy that helps reactants to react. Enzymes catalyze the reaction.
2. Describe how a substrate interacts with an enzyme.
-Subscrate fits into an enzyme and get easily reacted