Saltar la navegación

6.2. Inert, living, organic and inorganic matter

Inert matter and living matter

Two types of matter can be found in nature:

  • Inert or inanimate matter is made up of inorganic matter and has no life. The water, the soil, the rocks, etc. They are made of inert matter. Inert matter has no life.
  • Living matter is what constitutes living beings, and is made up of organic and inorganic matter.
    • Organic matter is made up of organic molecules produced by living things. These molecules are complex and contain carbon, such as carbohydratesproteinslipids, or nucleic acids.
    • Inorganic matter does not contain carbon (with some exceptions) and is not manufactured by living beings, but by chemical reactions that occur in nature. These molecules are simple, such as mineral saltswater, etc.

Composition of living matter

Living matter is made up of about seventy elements. These elements found in living matter are called bioelements, and will combine to give rise to biomolecules or immediate principles.


Bioelements are the chemical elements that are part of organic matter. Although there are many chemical elements, most living things are made up of the same chemical elements.

According to their abundance, several types of bioelements are distinguished:

Primary bioelements

96% of living matter is made up of oxygencarbonhydrogennitrogenphosphorus and sulfur. Although oxygen is the most abundant bioelement in living matter (62.81% in humans), the most representative element is carbon, which is the basic skeleton of all organic molecules.

Carbon (like silicon in silicates) can be bonded to four other atoms as if it were a tetrahedron with carbon in the center and the other atoms at the four corners. If it joins other carbons it can form long linear or cyclic chains.

El carbono se sitúa en el centro y en los cuatro vértices los cuatro átomos que se enlazan con el carbono.
Public Domain,

Secondary bioelements

Secondary bioelements appear in living matter in less quantity than primary ones, forming approximately 4% of living beings. Some secondary bioelements are, for example, calcium (Ca), sodium (Na), magnesium (Mg), potassium (K), etc.

Trace elements

Trace elements appear in living beings in amounts less than 0.1%, although they are essential for life. For example, iron (Fe), copper (Cu), iodine (I), etc.


Bioelements combine to form biomolecules or immediate principles. Two types of biomolecules are distinguished:

  • Simple: when the molecules are made up of atoms of the same chemical element, as is the case of molecular oxygen (O2) and molecular nitrogen (N2).
  • Compound: when molecules are made up of atoms of different elements, such as water (H2O). Compound immediate principles can be:
    • Inorganic. For example, water, mineral salts (carbonates, phosphates, etc.) and carbon dioxide (CO2). Inorganic biomolecules are also found in non-living matter.
    • Organic. Formed mainly of carbon and hydrogen, such as carbohydrates, lipids, proteins and nucleic acids.

Inorganic biomolecules

Some examples of organic biomolecules are water, mineral salts and carbon dioxide (CO2).

  • Water is the molecule that has the greatest presence in living beings. Water is the means of transporting substances, it helps maintain a constant temperature, and it is where the chemical reactions of living beings take place.
  • Mineral salts can be found in living beings in three forms: precipitated (skeletons, shells,...), dissolved or associated with organic substances.

Organic biomolecules

Organic molecules are only found in living matter. The biomolecules or immediate principles are:

  • Carbohydrates (or carbohydrates or sugars). They have energetic and structural function. For example, glucose or sucrose.
  • The lipidFats and oils have an energetic and structural function.
  • The proteinsThey have many functions, highlighting the structural, regulatory, defensive, transporter function, etc. For example collagen or hemoglobin.
  • Nucleic acids. They contain genetic information.

As you can see, atoms are grouped into biomolecules. Living matter is organized in increasingly complex levels of organization, forming cells, tissues, organs, devices and systems, until the living being is constituted.