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		Bio 220 Lecture 5 Membranes and transport
		Campbell,		65-68, phospholipid structure, use to understand membranes 130-122, evolution of membrane model [FYI] 132- top 135, membrane structure, understand Fig. 8.5 135-top 143, 143-144, endocytosis and signal transduction [later]
		Today, we're going to talk about how things get into and out of cells [!] I. Functions of the plasma membrane The plasma membraneforms the boundary between the inside and the outside of the cell. Q. Does it form an impermeable wall to protect the contents of the cell? II. Selective barrier A. Solutes that move across Q. If you were designing a cell, what kinds of things would you want to get intoit from the outside? H2O -for photosynthesis O2- for respiration CO2- for photosynthesis sugars (glucose, sucrose) - for food building blocks (amino acids, nucleotides, sugars) -for macromolecular synthesis ions Vitamins, peptides, even proteins What kinds of things would you need to get out ofthe cell? wastes O2/CO2 sugars - to store elsewhere ions Some of these things are small, unchargedmolecules, others are large, bulkythings or chargedmolecules. These different kinds of molecules have