What are biomolecules?

We explain what biomolecules are and how are organic and inorganic biomolecules. What are its functions and importance.

1. What are biomolecules?

Biomolecules or biological molecules are all those substances proper to living beings , either as a product of their biological functions or as a constituent of their bodies, in a huge and varied range of sizes, shapes and functions. The six main sets of biomolecules are carbohydrates, proteins , lipids , amino acids, vitamins and nucleic acids.

The body of living beings consists mainly of complex combinations of six primary elements, which are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and sulfur (S). This is because these elements allow:

• the formation of highly stable covalent bonds (sharing electrons), whether single, double or triple;
• the formation of three-dimensional carbon skeletons;
• the construction of multiple functional groups with extremely different and particular characteristics.

For this reason, biomolecules are usually made up of these types of chemical elements . All of them share, in addition, a fundamental relationship between structure and functions, which also involves the environment in which the biomolecule takes place: for example, lipids have a hydrophobic side, that is, that repels water , so they are usually organized in the presence of it so that the hydrophilic ends (attracted by water) are in contact with the environment and the hydrophobes remain in their shelter. These types of functions are key to the understanding of the biochemical functioning of living organisms .

Depending on their chemical nature, biomolecules can be classified as organic and inorganic , as will be seen below.

2. Inorganic biomolecules

There are biomolecules common to living beings and inert bodies , but they are nevertheless indispensable for the existence of life . These types of molecules are not based on carbon, as is the case with organic chemistry, but can present various types of elements, attracted to each other by their electromagnetic properties.

Some examples of inorganic biomolecules are water, certain monoatomic gases such as oxygen (O2) or hydrogen (H2), or inorganic salts such as anions and cations.

3. Organic biomolecules

On the other hand, there are organic biomolecules, that is, based on the chemistry of carbon and that are the product of the body’s own chemical reactions or the metabolism of living beings. Its atomic constitution is similar to theirs, although they may also present unusual elements, such as transition metals : iron (Fe), cobalt (Co) or nickel (Ni), then calling themselves trace elements and being indispensable, although in moderate quantities , for life.

Any protein, amino acid, lipid, carbohydrate, nucleic acid or vitamin is a good example of this type of biomolecules.

4. Functions of biomolecules

Biomolecules can have very different functions, such as:

• Structural functions. Proteins and lipids serve as support material for cells , giving structure to the body and allowing the generation of membranes, tissues, etc.
• Transport functions Other biomolecules serve to mobilize nutrients and other substances throughout the body, inside and outside the cells, joining them through specific bonds that can then be broken.
• Catalysis functions Certain specialized proteins make up enzymes , substances that accelerate, slow down, trigger or inhibit certain bodily functions, keeping the organism under control. In that sense, proteins and certain lipids function as chemical messengers of the body.
• Energy functions. The biochemical energy comes from certain reactions that take place within the body of living beings, either autotrophically (composing carbohydrates of inorganic matter ) or heterotrophic (obtaining carbohydrates of organic matter consumed), through an oxidation metabolism of the glucose that breaks its bonds and releases the energy contained in them. In that sense, lipids can also serve as the body’s energy reserve.
• Genetic functions. Inheritance in living beings is possible thanks to the existence of DNA and RNA , nucleic acid chains that contain the genetic information of living beings, through a complex and unique sequence of nucleotides that determine the exact sequence of amino acids that make up , as an instruction set, the composition of body proteins.

5. Importance of biomolecules

Biomolecules are important not only because they fulfill vital functions of support, regulation and transport of the body of living beings , but because they integrate their bodies themselves, that is, our bodies are made of them. Biomolecules integrate to form larger compounds successively, to form the cells and various tissues of the body. Without them, we simply could not exist.

6. Bioelements and biomolecules

The chemical elements from which the biomolecules are composed are called bioelements , and we have detailed at the beginning: Carbon (C), oxygen (O), hydrogen (H), nitrogen (N), sulfur (S) and phosphorus (P). With only these six elements, 99% of the living matter of all known living beings is composed. They are also known as primary bioelements: the fundamental bricks of the building of life.

On the other hand, secondary bioelements are those that, although indispensable for life and for the proper performance of the body, are required in moderate quantities and for specific purposes, such as sodium (Na), calcium (Ca), magnesium (Mg ) and potassium (K).

And finally there are the trace elements, which as the name implies are necessary but in very low amounts (0.1% of the body’s bioelements), such as iron (Fe) and iodine (I).