These ten essential amino acids are obtained from two sources. Source number one are dietary sources. So we can ingest protein, break down the protein into amino acids, and then use the amino acids for some type of process. And the other source of amino acids are the breakdown of preexisting proteins found inside our body, inside our cells. So recall that we ingest food, and then that food, if it contains protein, it makes its way into the lumen of the stomach. Now, in the lumen of the stomach, we have a low PH, a high acidity, an acidity of about two.