First you put the pizza to your mouth and take a bite. Then after you chew up your bite, you begin to swallow it and it goes down your throat. Then protein generally takes the form of very complex molecules, arranged in chains of amino acids. So the bonds binding these complex molecules together must first be broken down. This digestive process begins in the stomach, where hydrochloric acid, attacks the protein molecules separating them and breaking them down into amino acids.
Digestion of proteins continues into the first segment of the small intestine. Then trypsin breaks down a protein into single amino acid molecules, through a process called hydrolysis. During hydrolysis, a water molecule is inserted between the two amino acids which are bonded together. This breaks the bond between them. After the breakdown, the amino acids are small enough to pass through the intestinal lining into tiny veins in the villi.
Next the amino acids are distributed by both red blood cells and by the liquid blood plasma to tissues throughout the body where they are used in the creation and repair of cell structures. Such is the demand for protein, the body maintains a constant balance of amino acids in the blood.
Chemical Structure
Protein are made up of elements such as carbon, hydrogen, nitrogen, phosphorus, oxygen, and sulfur. All proteins are polymers of amino acids, and consist of a sequence of 20 different amino acids, also referred to as residues. For chains under 40 residues the term peptide is frequently used instead of protein. In order to understand the functions of proteins at a molecular level, it is often necessary to determine the dimensional structure of proteins.
Levels of Protein Structure
1) Primary structure - the amino acid sequence of the peptide chains.
2) Secondary structure - highly regular sub-structures (alpha helix and strands of beta sheet) which are locally defined, meaning that there can be many different secondary motifs present in one single protein molecule.
3) Tertiary structure - three-dimensional structure of a single protein molecule; a spatial arrangement of the secondary structures. It also describes the completely folded and compacted polypeptide chain.
4) Quaternary structure - complex of several protein molecules or polypeptide chains, usually called protein subunits in this context, which function as part of the larger assembly or protein complex.ure - three-dimensional structure of a single protein molecule; a spatial
References-
Collins, A. (2000-2007). Digestion Of Protien. Retrieved November 18, 2008, from Digestion In Digestive Track: http://www.annecollins.com/digestive-system/digestion-of-protein.htm
Fisher, M. (2004-2005 ). Pizza Ingrediants. Retrieved November 18, 2008, from The Food Museum: http://www.foodmuseum.com/pizzaingredients.html
Steven Dowshen, M. (2007, March). Your Stomach & Digestive System. Retrieved November 18, 2008, from KidsHealth: http://kidshealth.org/kid/htbw/digestive_system.html
