BIO 1000 Lecture Notes - Lecture 12: Endoplasmic Reticulum, Nuclear Membrane, Endomembrane System
4 Mar 2017
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Document Summary
Many of the internal membranes in a eukaryotic cell are part of the endomembrane system. These membranes are either directly continuous or connected via transfer of vesicles, sacs of membrane. In spite of these connections, these membranes are diverse in function and structure. The thickness, molecular composition and types of chemical reactions carried out by proteins in a given membrane may be modified several times during a membrane"s life. The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and the plasma membrane. The endoplasmic reticulum manufactures membranes and performs many other biosynthetic functions. The endoplasmic reticulum (er) accounts for half the membranes in a eukaryotic cell. The er includes membranous tubules and internal, fluid-filled spaces called cisternae. The er membrane is continuous with the nuclear envelope, and the cisternal space of the er is continuous with the space between the two membranes of the nuclear envelope.
