LIFE 120 Lecture Notes - Lecture 3: Endoplasmic Reticulum, Nuclear Membrane, Endomembrane System
Document Summary
Ribosomes: complexes of ribosomal rna (rrna) and protein. The nucleolus is located within the nucleus and is the site of ribosomal (rrna) synthesis. Ribosomes carry out protein synthesis in two locations. On the outside of the endoplasmic reticulum (rough er) or the nuclear envelope (bound ribosomes) The endomembrane system regulates protein traffic and performs metabolic functions in the cell. These components are either continuous or connected thorough transfer by vesicles. The endoplasmic reticulum (er) accounts for more than half of the total membrane in many eukaryotic cells. The rough er membrane is continuous with the nuclear envelope. There are two distinct regions of er: smooth er: lack ribosomes, rough er: surface is studded with ribosomes. The smooth er: synthesizes lipids, metabolizes, carbohydrates, detoxifies drugs and poisons, stores calcium ions. The rough er: has bound ribosomes, distributes transport vesicles proteins surrounded by membranes. Modifies products of the er (proteins or phospholipids) Sorts and packages materials into transport vesicles.
