When doing the starch test.....How can you explain that light necessary for photosynthesis?

Question

Also why is chlorphyll necesssary for photosynthesis?
I couldnot answer this question for my cousin to good.......I told her photo means light and synthesis means.........a plant needs light for photosynthesis.

Answer 1

synthesis means "combining" or "bringing together"

Light is energy - it provides the energy that plants need to change the chemical bonds of the chemical molecules that are present in leaves into the sugars that the plant uses (and people use) for energy. Chlorophyll takes the CO2 out of the air and combines it with water to make glucose. Chlorophyll also contains other molecules and elements, which is why plants are so healthy to eat.

The chemical formula for chlorophyll is:
C55H72MgN4O5

Answer 2

yeah

chloroplasts are large molecules with a single magnesium atom in the middle, sort of like the iron in hemoglobin, I think a photon hits that one Mg atom and thats the business part of it, The CO2 gets split there eventually combining with water to make glucose which combines to make cellulose (wood)