Amino Acid

Hemoglobin is a protein made up of polypeptide chains of amino acids
Hemoglobin molecule. Getty/Encyclopaedia Britannica/UIG

Amino acids are the molecular building blocks of proteins. Proteins are a very important biomolecule that not only helps in the structure and function of living things, but also determine all of the genetic traits an individual shows. Proteins are created from a combination of polypeptide chains made up of the amino acid building blocks held together with peptide bonds.

There are 20 total amino acids in living things that are both created within the body, and humans need to obtain some amino acids through consuming foods that contain those essential amino acids.

Then, these amino acid building blocks are put together through the process of translation to create a polypeptide chain. That chain can join up with others in specific shapes to make one of thousands of different proteins - from structural proteins to gene expression to enzymes - designed to do different things.

During translation, amino acids are attached to a specific transfer RNA (tRNA) that has an anticodon that will complement a messenger RNA (mRNA) sequence that codes for that specific amino acid. The tRNA brings the correct amino acid over to the mRNA sequence and then ribosomal RNA (rRNA) facilitates the binding of one amino acid to another in the correct order determined by the mRNA sequence. Once the polypeptide is complete, it is released and can continue on to make a protein.

A mistake, or mutation, in the process of translation where a wrong amino acid is placed in the chain can cause significant issues.

Many will hinder the polypeptide from creating the right shaped protein and the protein is then inactivated. This can lead to microevolution where some traits or processes are turned off in an individual. This may be beneficial or harmful depending on what is considered a favorable adaptation for the environment the individual lives in.

If the change in amino acid is desirable, then natural selection will "choose" that individual to live long enough to reproduce and pass down this new amino acid sequence.