Biomolecules: what are they, types, functions and characteristics

Life, at the zoo level, refers to the set of parameters that differentiate animals, plants, fungi, protists, archaea and bacteria from the rest of the natural realities, or in other words, from the abiotic (non-living) portion of the ecosystems. Knowing that a stone is not alive is simple, but, for example, at what point would viruses fall? What about viroids and prions, basic infectious agents that are little more than a strand of RNA or a misfolded protein?

It is not our intention to get entangled in metaphysical issues, but it is necessary to know that what generates life, in many cases, is not at all clear. Beyond homeostasis, growth, reproduction and differentiation, there are few better definitions to define life as the following: "what happens between the states of birth and death."

Anyway, if all living beings have something in common (apart from the presence of at least a cell) is that they are composed of 4 essential bioelements: carbon, hydrogen, oxygen and nitrogen. Based on these 4 chemical pillars,

all the biomolecules that make up each of our cells arise and, therefore, they make life possible on planet Earth. If you want to know everything about this topic, keep reading.

• Related article: "The most important parts of the cell and organelles: an overview"

What are biomolecules?

Biomolecules are the chemical compounds that form the living matter of all beings that inhabit the Earth. They result from the union of bioelements by chemical bonds, among which those of the covalent type stand out. These universal biomolecules are amino acids, carbohydrates, lipids, proteins, vitamins, and nucleic acids.

These molecules are constantly repeated in all living beings on the planet, something with very clear implications. Faced with this scenario, there are 2 possible options: either every living entity comes from the same common ancestor or, failing that, they have appeared independently different types of living beings with the same chemical composition throughout history, something highly unlikely.

This is where the principle of ockham razor, which raises the following: of two theories with equal conditions, the simplest will surely explain the problem posed. Thus, the homogeneous existence of biomolecules in all taxa confirms, in the most rational way possible, that all living beings have irradiated from the same ancestor.

Before we get ahead of complex issues, we are interested in dedicating a small space to bioelements, the pillars on which biomolecules are chemically supported. We will be quick.

Bioelements

Bioelements are chemical elements that are present in all living beings, either in atomic form or as members of biomolecules. Although more than 60 elements of the entire periodic table can be found in the tissues of living beings, only 25 are universal and inalienable.

Furthermore, 96% of the mass of almost all cell bodies corresponds to only 6 bioelements: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and sulfur (S), or CHONPS, for the friends of the rules mnemonics.

These 6 elements are the basis of biomolecules, due to the following properties that present:

• They allow the formation of covalent bonds between them (they share electrons). These bonds are very stable and allow the formation of biomolecules.
• Carbon atoms can form three-dimensional skeletons, allowing living things to present very different compounds based on their carbon skeleton.
• Bioelements allow the formation of double and triple bonds between them, as well as the synthesis of various structures (branched, cyclic, etc.)
• With few bioelements attached, a large number of functional groups can be synthesized, with different chemical and physical properties.

Based on all these premises, it is founded from the simplest bacteria to the entire human body. At the end of the day, we must not lose perspective of the following fact: biological complexity is determined by cell number and organization, but the basal substrate is always the same.

The types of biomolecules

Here is a list of the types of biomolecules present in the body of all living beings.

1. Amino acids and proteins

Amino acids are organic molecules with an amino group (-NH2) at one end and a carboxyl group (-COOH) at the other. They are the basis of proteins, although they can also perform other functions in the human body. An example of this is GABA (γ-aminobutyric acid), since it is an amino acid that is not present in our proteins and that also acts as a neurotransmitter in the nervous system.

There are many types of amino acids, but only 20 of them encode the proteins of living beings. A protein is such when the chain of amino acids joined exceeds 50-100 units or, failing that, reaches a mass of 5000 amu (unified atomic mass unit). Proteins are also considered as biomolecules in themselves (although larger and more complex), so they can be included in the same category as these biomolecules that make them up.

• You may be interested in: "What is an amino acid? Characteristics of this type of molecules "

2. Carbohydrates

Carbohydrates (also known as carbohydrates) They are biomolecules well known for their importance in nutrition, since among them are free sugars, starch, glycogen and many other substances.. They are always associated with a high energy content (1 gram provides 4.5 kcal), so they are linked to the storage and burning of energy in most living beings. Without going any further, in humans the greatest short-term energy reserve is not fat tissue: it is actually glycogen.

Due to its excellent energy properties, the World Health Organization (WHO) estimates that approximately 55-60% of the total caloric intake of a human being should be based on carbohydrates. Reaching this value is not difficult, since carbohydrates such as starch are found abundantly in bread, corn, potatoes, rice, cereals, legumes and many dairy products.

3. Lipids

Lipids are generally known as fats, consisting mainly of carbon, hydrogen and, to a lesser extent, oxygen. This heterogeneous group includes fats or oils, phospholipids and fatty acids (saturated, monounsaturated and polyunsaturated).

Foods high in lipids should account for 30-35% of your total caloric intake, so contrary to popular belief, fats are not bad per se. Human fat tissue has hormonal properties, allows long-term energy storage, protects us against mechanical damage and many other things.

• You may be interested in: "Types of fats (good and bad) and their functions"

4. Vitamins

Vitamins are very different compounds among them essential for life. These substances are generally known as “micronutrients”, therefore, despite being necessary in quantities Minimal, they perform a series of tasks on our body that cannot be replaced by other compounds. Vitamin A, vitamin C and vitamin E are clear examples within this group.

5. Nucleic acids

Nucleic acids do not require presentation: we are talking about DNA and RNA. The first is the library of life, as it encompasses all the genetic information necessary for cellular metabolism and, therefore, the survival of all our cells, organs and tissues.

DNA also contains the basis of heredity and evolution, because thanks to it, mutations and characters are inherited that change the genotype and phenotype of the species throughout the weather.

6. Inorganic biomolecules

As its name indicates, they are not organic in nature, but they still play a key role in the formation and maintenance of organisms. A clear example of an inorganic biomolecule is water (H20), which accounts for 70% of the total cell weight.

Resume

As you have seen, defining the term "life" becomes a little easier when we understand that, after all, we are all one conglomerate of 25 organic compounds, especially 6 bioelements: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and sulfur (S). When we reduce morphological complexity to its minimum, we discover that a bacterium and a human cell are almost more alike than different.

After all, almost everything around us is carbon and other organic elements, in one form or another. From the tuber of a plant to the liver of a human being there are thousands of years of evolution of through, but also a similar functionality and a similar chemical composition at the level elementary.

Bibliographic references:

• Fuentes-Quero, F. (2016). Bioelements and biomolecules: didactic unit for high school.
• The carbohydrates, asturnatura.com. Picked up on March 10 in https://www.asturnatura.com/articulos/glucidos/
• Lipids, puleva. Picked up on March 10 in https://www.lechepuleva.es/corazon-sano/lipidos
• Macarulla, J. M. (2021). Biomolecules. Reverte.
• Mora, J. G. (2003). Biological foundations of physical exercise. Wanceulen SL.
• Rodríguez, P. M. (2019). The words in things: knowledge, power and subjectivation between algorithms and biomolecules. Technology & Society, 95.
• Sarria López, Á. D. (2015). Biomolecules.
• Vitamins, Supradyn.es. Picked up on March 10 in https://www.supradyn.es/vitaminas-y-minerales