Calcium: The mineral that strengthens bone and teeth uses calcium. Also important in nerve synaptic transmission of nerve impulses and muscle contraction. Regulates the cell wall construction in plants. Phosphorus: Part of the phosphate groups in ATP and DNA molecules. In plants it is needed for cell reproduction and division. It is part of the cell membrane. Iron: found in the structure of hemoglobin and essential for the production of red blood cells. It is involved in the light energy transferring compounds involved in photosynthesis in plants. Sodium: Major ion associated with the propagation of a nerve impulse. Can replace potassium in some plants. Sulfur: It is a component of amino acids.
These organic compounds can also have amounts of nitrogen, calcium and phosphorous. They may have varying small amounts of other elements called “trace elements” like potassium, iodine, sulfur, iron, magnesium and sodium.
Living things also need inorganic compounds like water and salts.
Water is an essential part of every living thing. Plants use water in deriving some of their nutrients from minerals in the soil. These minerals have to be dissolved in water in order to be absorbed by the plants.
Water being liquid can easily hold and transport other materials. Water provides a way for substances to reach all the cells in an organism.
Animals and especially man depend much on water. Water is taken into the body by eating plants and meats and by drinking beverages. Humans can go for a month without eating but will die in 3 to 5 days without water because our bodies are made up of about 70 percent water. The body uses water in maintaining its temperature, breathing, digesting food, and lubricating moving joints.