Reviewing the Basic Definitions lesson may help with some of the terminology in this lesson.
The human body doesn't store protein. It may seem weird, but we break down protein into amino acids in order to make new proteins in our body. Not all of the amino acids are used that way, but a lot are.
This process of creating the new stuff is called synthesis. The DNA of the cell has a certain part telling how to make a protein. It needs to get it to the ribosome in the cell, so a messenger takes the information from the DNA and carries it to the ribosome. This messenger is called mRNA (messenger RNA). The messenger's only job is to carry the information to the ribosome. The ribosome still needs to get it. Different RNA that floats in the cytoplasm of the cell take the information from the messenger and transfers it to the ribosome. This RNA is called tRNA (transfer RNA).
In the Protein Breakdown to Absorption lesson, we touched on the structure of an amino acid. The tRNA and the ribosome work together, and amino acid chains are built. If the tRNA requires a certain amino acid in the chain and that amino acid in the cell doesn't exist, the chain cannot be completed. However, assuming all the required parts are there, the body can make amino acids to continue the chain.
Proteins are vital. Among other things, they make up: