BIO130H1 Chapter : Membrane Structures.docx

• School: UTSG
• Department: Biology
• Course: BIO130H1
• Professor: Jane Mitchell

Document Summary

Plasma membrane: encloses cell, defines boundaries, maintains differences b/w cytosol and extracellular environment: contains protein sensors (receptors) allows cell to change behaviour according to environment/ transfer info, also accepts signals from surrounding cells. Inside eukaryotic cells, membranes of endoplasmic reticulum, golgi apparatus, mitochondria, and other membrane enclosed organelles maintain the characteristic differences b/w contents of each organelle and cytosol. Ion gradients drive transmembrane movement of solutes, or transmit electrical signals in nerve and muscle cells. All membranes have thin lipid layer and protein molecules which are held together by noncovalent interactions. The lipid bilayer (5nm thick) provides basic structure for all cell membranes. All lipids are amphiphilic: phospholipids: have polar head, 2 hydrophobic hc tails (fatty acids). One tail has one or more cis- double bonds (unsaturated) other has single bond (saturated) Cis double bonds create a kink in tail: phsophoglycerides: have 3 carbon glycerol backbone.