Activation Energy: The minimum amount of energy required for a chemical reaction to occur. This would be equivalent to the initial push needed to start pedaling uphill on your bike.
Catalyst: A substance that speeds up a chemical reaction without being consumed by it. Like having an electric motor on your bike helping you pedal uphill easier.
Photosynthesis: A process used by plants and other organisms to convert light energy into chemical energy; this is an example of an endergonic reaction because it requires sunlight (energy).