Explain the 'induced fit' model of enzyme-substrate interaction.

Induced fit is when the active site of an enzyme changes its shape to perfectly bind to the substrate, creating an enzyme-substrate hug.

What happens to an enzyme after it catalyzes a reaction?

The enzyme is not used up in the reaction and can be used again to catalyze another reaction.

I can describe how chemical reactions break down and build up molecules in living things.

1
Enzymes are mostly proteins that speed up reactions by binding to substrates at the enzyme's active site.
2
Enzymes are considered catalysts because they are not used up in a reaction and can be used over and over.
3
If the pH or temperature is not ideal, an enzyme can become denatured, which means it loses its shape and can no longer function.