BIOL150 Lecture 6: biol 150 Lecture 6: biol 130 Lecture 6: Unit 6 - Biological Membranes
14 Dec 2015
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Document Summary
Eukaryotic cells membrane bound organelles: encloses contents of entire cell, controls what comes in and goes out, signals get sent through membrane, nuclear envelope, double membranes of mitochondrion, endoplasmic reticulum, golgi apparatus, lysosomes/vacuoles, transport vesicles. Don"t flip between layers but move within. Alignment of phospholipid tails molecules move within a membrane leaflet. Cholesterol and membrane fluidity stiffer less fluid: cholesterol can make up to 50% of plasma membrane lipid in some animal cells. Temperature and membrane fluidity are fluid, and move freely. At and above room temperature" phospholipids in membranes. As temperature drops, fluidity (and permeability) decreases. At very low temperatures, hydrophobic tails pack together and. Transition temp = temp at which membrane gels" membrane gels" (solidifies) Fluid state must be maintained for normal cell function. Strategies for maintaining membrane fluidity: change composition of membranes. Desaturate fatty acids (to deal with cold: e. g. , cold water vs. warm water fish. Change the length of fa chains (yeast, bacteria)
