1. What important chemical group used by plants does oxygen form which includes phosphorus?
2. How does the polar nature of water affect the ability of a substance to dissolve in water?
3. Why is the polar nature of water important for plants?
4. Why does oxygen have to be continually added to the atmosphere by plants?
1. The energy molecule for most living things is ATP (adenosine triphosphate) which, as its name implies, contains three phosphorus atoms. Energy is stored in the bonds of the ATP molecule, and when it is used it releases energy and transforms to ADP (adenosine diphosphate.) Sunlight is electromagnetic energy which is converted by a plant's chloroplasts into ATP; that is used to power other reactions within the plant, one of the most important being the conversion of carbon dioxide and water into sugar and oxygen, in the process known as photosynthesis:
6CO2 + 6H2O + ATP = C6H12O6 + 6O2 + ADP
2. Because a water molecule has a slightly negative charge on one side, and a slightly positive charge on the other, (and therefore has "poles") ionically bonded molecules will break apart and dissolve in water.
3. The major mineral nutrients a plant needs contain the following atoms: Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, and Sulfur. All can form ionic compounds in the ground, and, (because of the polar nature of water) can dissolve in water, which can travel up the plant through its roots and be used in biochemical reactions. If water were not polar, or the compounds ionic and dissolvable in water, the plant could not synthesize the compounds its needs.
4. Oxygen is a waste product of photosynthesis, and is released into the atmosphere as long as the plant is photosynthesizing. (See equation under response #1.)