What is Macromolecule:
A macromolecule is the union of a repeat of simpler biological molecules that reach high molecular weights. The 4 most important biological macromolecules in animal cells are carbohydrates, lipids, proteins, and nucleic acids.
In chemistry, 2 or more atoms that are held together in a stable, electrically neutral system are called a molecule. A macromolecule, therefore, is the union of several molecules to a larger one and is generally a polymer. Polymers are chains of 5 or more monomers or low weight molecules.
In this sense, macromolecules are used as a synonym for polymers as they are the basis of several of them, such as, for example, nucleotide polymers, which form the basis of nucleic acids: DNA and RNA.
Macromolecules are generally formed by dehydration synthesis. This means the formation of a covalent bond to join 2 monomers (synthesis) releasing a molecule of water (dehydration).
Most important macromolecules
The most important biological macromolecules in humans are carbohydrates, lipids, proteins, and nucleic acids.
These 4 macromolecules make up a large part of the dry weight of the cell and most of the wet weight is due to water molecules.
They are classified as such due to their polymeric nature (polymer base) and due to their large size, however, they present different characteristics. Among the 4 most important macromolecules, the lipid is the only one that generally does not form polymers and they are smaller in size.
See also Polymer.
Carbohydrates are made up of glucose monomers with different binding and branching patterns, such as starch, glycogen, and cellulose. When you chew these carbohydrates, what you do is break the macromolecule into smaller structures so that they are easier for the body to absorb.
The enzymes that contribute to the bond-breaking process are generally given -ase-terminated names, such as protein-degrading peptidases, maltose-degrading maltase, and lipid-degrading lipases.
The reactions that break the bonds of the macromolecules is called hydrolysis, where in addition to releasing smaller units, it incorporates a water molecule (H20).
Although lipids are not normally polymers and are smaller, they are included in the group of most important macromolecules. Simple lipids are compounds of carbon, hydrogen, and oxygen attached to one or more fatty acid chains, which include: fats, oils, and waxes.
Within complex lipids are phospholipids, specialized lipids that form the plasma membrane, and steroids, such as cholesterol and sex hormones.
See also Lipids.
The great diversity of types and functions of proteins that we know of are composed of chains of 20 types of amino acid monomers. The synthesis or translation of proteins is carried out in the ribosomes, with the genetic information of the DNA that arrives thanks to the messenger RNA.
The successive union of amino acids and molecules to form a protein is a good example of dehydration synthesis, a process in which bonds are formed by joining small molecules until they become macromolecules.