BIOL 134 Lecture Notes - Lecture 5: Gram-Positive Bacteria, Passive Transport, Gram-Negative Bacteria
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Phospholipid bilayer: hydrophilic water loving , hydrophobic water fearing , hydrophilic head, hydrophobic tails, water on the outside, hydrophilic molecules will push out hydrophobic molecules & vice-versa, slide 106 has phospholipid structure, self-organized. Phospholipid bilayer: the plasma membrane provides selective permeability, water can get across freely, allowing osmosis, principle of diffusion = things move from high concentration to low concentration. Leads to normalization equal numbers on both sides: a solute added to the outside will increase movement from the inside to outside. Water rushes into the cell osmotic lysis (cell membrane pops: hypertonic. Water rushes out plasmolysis (cell sucked dry: bottom line: water chases solutes. Phospholipid bilayer: passive transport: requires no energy output, depends on the process of diffusion. Small, uncharged molecules like o2 and co2 can cross by diffusion. Facilitated diffusion: proteins help molecules cross the membrane by diffusion.