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:
96% of living matter is made up of oxygen, carbon, hydrogen, nitrogen, phosphorus 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.
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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 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.
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 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 lipid. Fats and oils have an energetic and structural function.
- The proteins. They 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.