A comparative study of what ionic compounds and molecular compounds are will help you understand the differences between the two of them.
What are Inorganic Nutrients?
There are many different types of nutrients consumed by organisms throughout various food chains and ecosystems, that are spread across the whole planet. Inorganic nutrients are an important part of food chains, and are also essential for the completion of the entire cycle of generation and degradation of food.
The chain of generation and degradation of food is considered to be a highly organic process. It originates with the photosynthesis that is carried out by plant leaves, and ends upon the decomposition of animal waste by micro organisms. The principle matter involved in this process is carbon, which makes the process an organic one. Indeed, the nutrients that are passed on from one organism to another, include carbon based compounds, such as sugars, carbohydrates, fats, and proteins, but the existence, as well as importance, of inorganic compounds (not having a carbon basis) cannot be denied.
As mentioned above, the cycle of food starts with plants and photosynthesis. The leaves of the plants generate carbon based compounds, such as sugars, starch, carbohydrates, etc. Eventually, these are transferred to animals, and in the end, these same sugars are broken down into simpler elements and compounds, that are again organic in nature. There are however, numerous elements and compounds that are inorganic in nature, but are absolutely essential for the completion of the aforementioned cycle.
List of Inorganic Nutrients
Here is a small list of inorganic elements that are required to complete the food cycle. It must be noted that the following nutrients are an absolute necessity for almost all living organisms. Though the role of such nutrients is important, their presence, volume wise, is relatively negligible and almost immeasurable.
Boron is a very important nutrient, which is required by most of the vascular plants and algae. This element is an absolute necessity, as it helps in maintaining cell integrity, notwithstanding if the organism is a multicellular or a unicellular one.
Calcium is required by almost every organism. In animals, calcium has an important place, as it helps in building of their bodies. The bones of all the skeletal animals are mainly made up of calcium. In some cases, where calcium is taken through non-elemental forms such as calcium carbonate, it is of organic nature. Though, when it is utilized by the body, it assumes an elemental form, which is inorganic.
Another important nutrient which is essential for survival, is magnesium. Magnesium is required for many aspects, such as DNA and RNA, or even for the production of 300 different enzymes in the human body. Plants too require magnesium to maintain their chlorophyll.
Phosphorus is invaluable for all organisms, multicellular or unicellular alike. This element is used by every known form of life, in different cellular operations, such as building the cell membrane, as well as building the DNA or RNA. It must be noted that phosphorus is rarely used in a direct elemental form. In most cases, this nutrient is used in the form of compounds.
Another important element that is converted into useful compounds by the cells, is sulfur. It is required by almost all living organisms. Right from DNA and cells, to enzymes and essential acids, sulfur is employed by living beings in countless processes.
Though these elements are not consumed by living beings in direct form, there are several modes of indirect consumption. For example, a sulfate ion is absorbed by plants through the soil, and is converted into sulfide and sulfur. In fact, water, which sustains all life on Earth, is also an inorganic nutrient.