Biomolecules: What They Are, Types, Functions And Characteristics
Life, at a zoological level, refers to the set of parameters that differentiate animals, plants, fungi, protists, archaea and bacteria from the rest of natural realities, or in other words, from the abiotic (non-living) portion of animals. 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 than the following: “that which passes between the states of birth and death.”
In any case, if all living beings have something in common (apart from the presence of at least one cell) it 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, make life on planet Earth possible. If you want to know everything about this topic, continue reading.
Biomolecules are 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 the covalent type stands out. These universal biomolecules are amino acids, carbohydrates, lipids, proteins, vitamins and nucleic acids.
These molecules are constantly repeated in all living beings present on the planet , something with very clear implications. Given this scenario, there are 2 possible options: either every living entity comes from the same common ancestor or, alternatively, different types of living beings with the same chemical composition have appeared independently throughout history, something highly unlikely. .
Here the principle of Ockham’s razor comes into play, which states the following: of two theories with equal conditions, the simplest will surely explain the problem posed. Thus, the existence of biomolecules homogeneously in all taxa confirms, in the most rational way possible, that all living beings have radiated from the same ancestor.
Before moving forward with complex topics, we find it interesting to dedicate a little space to bioelements, the pillars on which biomolecules are supported at a chemical level. We will be fast.
The bioelements
The bioelements They are chemical elements that are present in all living beings, either in atomic form or as members of biomolecules Although more than 60 elements from 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 friends of mnemonic rules.
These 6 elements are the basis of biomolecules, due to the following properties that present :
Based on all these premises, it is founded from the simplest bacteria to the entire human organism. 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
Below, we present 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), as 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 code for the proteins of living beings A protein is such when the chain of linked amino acids exceeds 50-100 units or, failing that, reaches a mass of 5000 amu (unified atomic mass unit). Proteins are also considered biomolecules in themselves (although larger and more complex), so they can be included in the same category as these biomolecules that make them up.
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 largest short-term energy reserve is not fatty tissue: in reality, it is glycogen.
Due to its excellent energetic properties, the World Health Organization (WHO) estimates that approximately 55-60% of a human being’s total caloric intake should be based on carbohydrates. Achieving this value is not difficult, since carbohydrates such as starch are abundantly found in bread, corn, potatoes, rice, cereals, legumes and many dairy products.
3. Lipids
The lipids They 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 with high lipid content should account for 30-35% of the total caloric intake ingested, so, contrary to what many people believe, fats are not bad per se. Human fatty tissue has hormonal properties, allows long-term energy storage, protects us against mechanical damage and many other things.
Vitamins are very different compounds, among them essential for life These substances are generally known as “micronutrients”, because, despite being necessary in minute quantities, 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 require no 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 inheritance and evolution, since thanks to it mutations occur and characters are inherited that change the genotype and phenotype of the species over time.
6. Inorganic biomolecules
As its name indicates, They are not organic in nature, but 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.
Summary
As you have seen, defining the term “life” becomes a little easier when we understand that, after all, we are all a 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 bacteria and a human cell have almost more similarities than differences.
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 involved, but also a similar functionality and a similar chemical composition at an elemental level.
