Changes

==Synthesis==

==Synthesis==

Proteins are synthesized by cytoplasmic structures composed of catalytic rRNA and proteins called [[ribosomes]]. Ribosomes translate information coded in mRNA (transcribed from genomic DNA, specific regions known as [[genes]]) after editing and manipulation by nuclear [[spliceosome]]s. The nascent protein is elongated in the ribosome through addition of different amino acids specified by codons (sets of three nucleotides) in the mRNA molecule. The formation of the protein chain requires the codon, a molecule of transfer RNA (tRNA) charged with a particular amino acid, and the tRNA's anti-codon. A molecule of water is expelled after each peptide bond is formed, hence the name "condensation reaction".

Proteins are synthesized by cytoplasmic structures composed of catalytic rRNA and proteins called [[ribosomes]]. A few peptides are synthesized in non-ribosomal reactions, such as glutathione. Ribosomes translate information coded in mRNA (transcribed from genomic DNA, specific regions known as [[genes]]) after editing and manipulation by nuclear and cytoplasmic [[spliceosome]]s. The nascent protein is elongated in the ribosome through addition of different amino-acyl moieties from the tRNA carrier. The start site and sequence of addition is specified by codons (sets of three nucleotides) in the mRNA molecule. The formation of the protein chain requires the codon, a molecule of transfer RNA (tRNA) charged with a particular amino acid, and the tRNA's anti-codon. A molecule of water is expelled after each peptide bond is formed, hence the name "condensation reaction".

After the protein has been generated, it is assisted by other proteins termed chaperones that aid in the formation of the proper conformation. A protein is always synthesized in one direction so, invariably, proteins also exhibit the physical property known as polarity. All [[polypetide]]s possess free N-terminal(Amine; NH2) and C-terminal (Carboxylic Acid; COOH) ends. The protein may then be further edited post-translationally by certain enzymes. Examples of such modifications include, [[isoprenylation]], [[palmitoylation]], [[myristoylation]], [[methylation]], [[acetylation]], N-terminal [[proteolysis]], and [[disulfide bond]] linkage. These modifications often have some bearing on the function and localization of the protein. After these processes occur, the protein can be transported to other sub-cellular organelles/locations such as the plasma membrane, golgi apparatus, endoplasmic reticulum, and vesicles where they perform their pre-programmed function. Vesicular proteins are usually shuttled to the plasma membrane, or reserved cytoplasmically for secretion at a later time.

After the protein has been generated, it is assisted by other proteins termed chaperones that aid in the formation of the proper conformation. A ribosomal protein is always synthesized in one direction so, invariably, proteins also exhibit the physical property known as stereoisomerism. All [[polypetide]]s possess free N-terminal(Amine; NH2) and C-terminal (Carboxylic Acid; COOH) ends. The protein may then be further edited post-translationally by certain enzymes, by for example a piece being cut out and the two halves re-ligated. Examples of other modifications include, [[isoprenylation]], [[palmitoylation]], [[myristoylation]], [[methylation]], [[acetylation]], N-terminal [[proteolysis]], and [[disulfide bond]] linkage. These modifications often have some bearing on the function and localization of the protein. After these processes occur, the protein can be transported to other sub-cellular organelles/locations such as the plasma membrane, golgi apparatus, endoplasmic reticulum, and vesicles where they perform their pre-programmed function. Membrane proteins are unfolded by a signal recognition particle, and then inserted into the lipid bilayer of a vesicle. Such vesicular proteins are usually shuttled to the plasma membrane, or reserved cytoplasmically for secretion at a later time.

==Nutrition==

==Nutrition==