CONCEPTS

What are macromolecules?

We explain what macromolecules are, their functions and their types of structure. In addition, natural and synthetic macromolecules.

  1. What are macromolecules?

Macromolecules  are huge molecules . They are generally the product of the union of smaller molecule units, known as monomers, through natural or artificial processes. That is to say, they are composed of thousands or hundreds of thousands of atoms.

These macromolecules can be of a biological nature, the result of the processes of living organisms, or synthetic, produced in laboratories by human hands.

The term macromolecules was coined in 1920 by Hermann Staudinger , Nobel Prize in Chemistry . Since then the term is used as more or less synonymous with polymers .

However, strictly speaking, this last term refers to chains of monomers that do not necessarily exceed 10 angstroms in diameter (10 -6 millimeters) and therefore have a size more similar to that of ordinary molecules. That is to say that not all polymers are macromolecules.

  1. Functions of macromolecules

Macromolecules can have very different functions , depending on which one we are talking about. For example, glucose macromolecules are an energy source for living organisms .

A very different example is the DNA macromolecule , which is basically a cell memory device used when synthesizing proteins or when it comes to cell replication. That is, macromolecules do not have a single specific function.

  1. Structure of the macromolecules

linear macromolecules dna
DNA is a linear macromolecule.

Generally, the smaller units that compose them are joined together by covalent bonds , whether by hydrogen bridges, Van der Waals forces or hydrophobic interactions. In any case, large structures thus comprise molecules that contain thousands of atoms arranged in fixed sequences, resulting in compounds of a very high molecular weight.

In addition, depending on their structure, macromolecules can be:

  • Linear . When they make long chains that repeat some order of monomers, joined together by head and tail.
  • Ramified . When each monomer can join other chains, forming branches (such as trees) of different sizes at a certain height of the main chain.

On the other hand, if in said chain the monomers are the same, repeating itself, a homopolymer will be said, while if they alternate with other monomers it will be a copolymer.

  1. Importance of macromolecules

The macromolecules differ from the rest of the natural and synthetic molecules in that they have a huge volume and molecular weight. As a consequence, its properties are more complex and useful than those of other molecules . For example, man-made polymers allow the creation of novel materials with unforeseen applications.

On the other hand, certain biological macromolecules perform complex tasks, either as a material and / or energy contributor to other processes, or as mechanisms of biochemical action , such as with insulin, the hormone regulating sugar in the human body , composed of 51 different amino acids.

  1. Natural macromolecules

glucose natural macromolecule
Glucose is a natural macromolecule that serves as a source of energy.

Natural macromolecules are usually very specific compounds that fulfill vital functions. In some cases they function as a metabolic input (such as carbohydrates) and in others they are structural molecules (such as lipids ).

They are also fundamental actors of extremely complicated processes, such as DNA and RNA , that participate in cell replication or mitosis . Some simple examples of natural macromolecules are starch, cellulose, glycogen, fructose, glucose or lignin present in wood.

  1. Synthetic macromolecules

On the contrary, synthetic molecules are, as the name implies, those artificially synthesized by humans , through various chemical processes in which the binding of monomers is controlled, enhanced or accelerated.

They are particularly important in the petrochemical and petroleum products industry, from which we obtain important polymeric organic materials, such as most plastics ( polyethylene , PCV), synthetic fibers (polyester, nylon ) or advanced materials (like carbon nanotubes).

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