What are proteins made of?

Proteins are made of amino acids which are the sub-units of this polymer. When joined in a long chain, the amino acids form a polypeptide. The prefix poly refers to many and the term peptide refers to the type of bond that forms between one amino acid and the next one in the long line of amino acids.

There are twenty different amino acids that form all the proteins in organisms. However, it is their arrangement that produces the thousands of different proteins- hair, muscle cells, enzymes, hormones, transporter proteins, etc. 

The blueprint of an organism is encoded in its DNA, a nucleic acid found in the nucleus. Using the information in this blueprint, an organism will be able to make the different proteins necessary for its survival.

The DNA is the chemical that makes up chromosomes. On the chromosomes are discrete units known as genes and each gene is the blueprint to make a particular protein.

The flow of information from blueprint to protein is-- DNA  in the nucleus is transcribed into mRNA, which leaves the nucleus and travels to the cytoplasm. Here, it attaches to a ribosome where the genetic code is translated into a protein. Transfer RNA carries the correct amino acids in order as per the mRNA transcript to build the growing polypeptide.

Eventually, a stop codon causes the mRNA to detach from the ribosome, which also breaks apart and the polypeptide undergoes further processing. It will eventually fold and take its three dimensional shape that is unique to that protein and it will be able to become a functional protein. 

In order to make proteins, the body must have a supply of amino acids. The essential ones must be consumed by eating foods that contain protein while the non-essential amino acids are ones that the body can synthesize on its own.