Biology 1002B Lecture Notes - Lecture 16: X-Inactivation, Chromatin, Chromosome
Document Summary
Poly a polymerase, ribosomal rna and transfer rna must pass through a nuclear pore in order to get from where it is they are synthesized to where they function. Proteins are targeted to the rough er, and then transported into secretory vesicles to the golgi apparatus. Some of these are then exported outside the cell. At the same time, endocytic vesicles are imported into the cell and fuse with the lysosomes, which break down endocytic food particles. Lysosomes can also be of use in digesting old mitochondria. So any enzymes that need to end up in the lysosomes need to be targeted appropriately for the rough er. The synthesis of membrane proteins is targeted to the er by a peptide tag that is first to emerge from the ribosome. However, this tag can only be found in the coding region where the final protein receives its function.