The Endomembrane System • The endomembrane system consists of: • Nuclear envelope • Endoplasmic reticulum • Golgi apparatus • Vesicles • Plasma Membrane
Endomembrane system, I -ER • Continuous with nuclear envelope TWO TYPES • Smooth ER • Rough ER
Smooth Endoplasmic Reticulum Smooth ER • Lacks significant number of ribosomes on external surface. Functions: • Makes lipids, phospholipids, and steroids. • Detoxifies poisons and toxins • Stores Ca+2 in muscle cells • Metabolism of Carbohydrates • Produce vesicles which contain newly produced proteins.
Rough Endoplasmic Reticulum • Cytoplasmic side is covered with ribosomes • Further manufactures and processes proteins from ribosomes destined to become secretory proteins (enzymes, hormones). • Makes phospholipids and embeds proteins in them: making new cell membrane.
Endomembrane system, II - Golgi • ER products are modified, stored, and then shipped • Made of flattened saccules (cristernae) of membrane. • cis face (receiving) & transface (shipping) • Creating vesicles
Export products Of Golgi Apparatus have three possible fates: 1. To extracellular environment. 2. Vesicles converted into: Lysosomewhich stores hydrolytic enzymes. Used to attack pathogen or break down dead or damaged cell. Cell recycler of the cell’s own organic material. Peroxisomeswhich store enzymes involved in peroxide metabolism. 3. Add more plasma membrane to the cell to facilitate growth.
The Cell Membrane • “The gatekeeper of the cell” • A thin, outer covering of the cell. • Controls what goes in and out of cell.
DRAMA TIMEEndomembraneSystem FEATURING: • Nuclear envelope • Endoplasmic reticulum • Golgi apparatus • Vesicles • Plasma Membrane