Nutrition Test Review sheet: ProteinsA. Structure1. Proteins are long chains of subunits seen as a 3-dimensional structure. 2. Basic unit of a protein is an amino acida) are made up of amino acids, always has a nitrogen, a carbon skelton with a hydrogen backbone, acid group and r- group(side chain) which differentiates one amino acid from another, and determines the structure and function. Structure and function of proteins determines their amino acid sequence. 3. Peptide Bond a) Links together two amino acidsb) Needs to be broken during digestionb. Dipeptides- two amino acids c. polypeptides- many amino acids-Each different protein has a unique amino acid sequence which is encoded in the cellular DNA a) DNA transcribed into RNA- RNA acts as a messenger and carries genetic information from DNA to site of protein synthesisb) RNA translated into protein1) Puts amino acids in correct orderProtein: (process)1. Part of DNA unwinds, and a section of its genetic code is transcribed into the mRNA inside the nucleus.2. The mRNA leaves the nucleus via a nucleus pore and travels to the cytoplasm.3. Once the mRNA reaches the cytoplasm, it binds to a ribosome. The code on the mRNA is translated into the instructions for a specific order of amino acids. 4. Amino acids are added to the growing amino acid chain and eventually a complete protein is produced. 5. Once the synthesis of the new protein is complete, the protein is released from the ribosome. The protein may go through further modifications in the cell or can be functional in its current state. B. Protein is an essential nutrient1. Essential amino acids (EAA) a) Cannot be made by the body b) Must be included in the diet to maintain optimal protein status.c) Provide a source of nitrogen for other compounds.d) Can be used as an energy source.2. Non-essential amino acids (NEAA)a. Amino acids that the body is able to make from other substances in the dietb. Provide a source of nitrogen for other compounds c. Can be used as an energy sourceDigestion- breakdown of proteins into the building blocks(amino acids) by breaking the bonds that link the amino acids. - Mouth: grinding and mixing if food, no protein digestion- Stomach: stomach acid causes protein denaturation (the first step in protein digestion which makes the protein biologically inactive by altering its folding structure causing it to open up and make it digestible) Pepsins: breaks down protein- Small intestine: pancreatic enzymes: breas down protein to amino acids and dipeptidesAbsorption: amino acids and dipeptides are absorbable (proteins [as whole proteins] aren’t except with infants and people with damaged intestines)Small intestine:- Amino acids are absorbed by different