BIOL 2020 Lecture Notes - Lecture 4: Oligosaccharide, Unfolded Protein Response, Proteasome
4 Mar 2018
School
Department
Course
Professor
Document Summary
Protoplasmic (p) face = side of the membrane (either from the cell or organelles) that faces towards the cytosol. Exoplasmic face (e) = side of the membrane (either form the cell or organelles) that faces towards the extracellular or the inside of the organelles. Membrane lipid synthesis: phospholipids are inserted into pre-existing membranes, phospholipids synthesis occurs on the p (protoplasmic) face, flippases are needed for phospholipids transfer to the e (exoplasmic) face. *lipids are carried from the er to the golgi via transport vesicles. Why is the lipid composition varies in different organelles: modification by enzymes, vesicle formation, phospholipids transfer proteins. Glycosylation: is the enzymatic process that attaches glycans (or polysaccharides) to proteins, lipids or other organic molecules. *the enzyme glycosyltrasnferase, which catalyzes the formation of glycosidic bonds, helps. *most membranes of the endomembrane system contain significant amounts of carbohydrates on the exoplasmic face. Occurs at the er; the entire oligosaccharide is made before being added to nascent peptide.
