How are proteins digested absorbed transported and assimilated in the body?
During digestion dietary proteins are broken into their basic building blocks known as amino acids.
Digestion of proteins beigins in the mouth via mastication and continues in the stomach where they are denatured by hydrochloric acid. Once they leave the stomach, protease enzymes in the small intestine continue to break the proteins into single amino agids or small chains of two or three amino acids.
The small digested protein remnants are absorbed via gacilitated diffusion or active transport in the small intestine. Once inside the intestinal cells, any existing chains of amino acids are broken up into single amino acids and then released into the bloodstream.
When ingested amino acids make it into the bloodstream, they become part of the body's amino acid pool. The amino acid pool also includes amino acids found in the other tissues primarily skeletal muscle and the liver. The blood with its circulating levels of amino acids, makes up the central part of the amino acid pool, which remains in equilibrium with the other compartments. This helps to maintian the blood's levels of amino acids, thereby serving as a constant and readily available source of amino avides for the body.
Amino acid absorption from the bloodstream into the cells of the body tissues occurs through facilitated diffusion. Once inside the amino acids can be used to make needed proteins through the processes of transcription and translation. Genes in the nucleus are transcribed to form mRNA. mRNA leave the nucleus and is translated by ribosomes, which attach the amino acids together to form the specific protein required.