Passage 5 Structure of Sugar make molecules of Atoms ofand oxygen are put together to dioxide sugar-a carbohydrate food substance The carbon comes from carbon eas in the air. Air enters through holes, called stomata, in the plant's leaves. e hydrogen and oxygen come from water. The water is taken up from the called soil by the plant's roots. The light energy is trapped by a special chemical chlorophyll Chlorophyll is green and gives green plants their color. The gas oxygen is left over at the end of photosynthesis and goes into the air.