Psychology of Exceptional Child Practice Test

There are 20 standard amino acids that make up most human proteins. Nine of them are essential for adults, meaning the body cannot make them in sufficient amounts and they must come from the diet. The remaining amino acids can be synthesized by the body, so they are non-essential. Subtracting the nine essential ones from the total gives eleven non-essential amino acids. (Note: in infants, some amino acids like arginine and sometimes histidine are considered essential or conditionally essential, which can change counts in certain texts. For typical adult nutrition, the count of non-essential amino acids is eleven.)