Chemical Reactions and Enzymes

Learning Objectives Explain how chemical reactions affect chemical bonds. Describe how energy changes affect how easily a

chemical reaction will occur. Explain why enzymes are important to living things.

Chemical Reactions

A chemical reaction changes one set of chemicals into another.

reactants productreactant products

Energy in Reactions

Chemical reactions that release energy occur spontaneously.

Chemical reactions that absorb energy require a source of energy.

Which reaction occurs spontaneously?

Activation Energy Activation Energy

Energy in Reactions Review

Reactants

Energy-absorbing

Occur spontaneously

Requires more energy to get started

Has a lower activation energy

Will proceed more quickly

Enzymes

Enzymes lower activation energy and speed up chemical reactions in cells.

Enzymes in the Body

Carbonic anhydrase speeds up this reaction by a factor of 10 million.

The Enzyme-Substrate Complex

Substrates

Product

Active Site

The active site of the enzyme and the substrate have complimentary shapes.

Substrate Enzyme

Active Site

The active site of the enzyme and the substrate have complimentary shapes.

Enzyme! The Play

Develop a short play or demonstration that illustrates how enzymes catalyze reactions.