The plant uses the sugar as its food. The oxygen comes out of the plant so we can breathe it. Photosynthesis only happens in green cells and in the daylight. Plants start carrying on photosynthesis and respiration if the plant has chlorophyll and sunlight. Plants give off oxygen only in the day time because photosynthesis needs sunlight, oxygen and chlorophyll to work.
Enzymes are a chemical substance in the plant.
Enzymes are proteins that speed up chemical reactions. Chemical reactions are when chemical substances mix together and make something else like when you mix baking soda and vinegar it makes a chemical reaction. Photosynthesis is a chemical reaction and enzymes are involved in the process of photosynthesis. See a picture . See a second picture .