Cell Bio Test 3 Notes - Cell Bio Test 3 Notes Lecture 14...

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Cell Bio Test 3 Notes Lecture 14 Organelles must have a membrane for separation (compartments) Ground cytoplasm Endoplasmic Reticulum - Membran e is continuous with outer nuclear m e m bran e - Has its own cytoplas m Ribosom e is not a n organ elle Peroxisom es- e nzym atic reactions occur inside a nd are sep arated by Two types of m e m bran es - Plas m a- surrounds cell (has outside contact) - Internal Plasma Membrane Required Filter not a barrier Lipid bilayer Thermodynamically stable (no energy needed to stay together) Fatty acid tails are hydrophobic and polar 4-5 nm thick Lipid backbone but has lots of proteins and carbs - Structural = lipids (50%) - Functional = proteins Lipids Phospholipids - 3 C sug ar alcohol (glycerol) attach ed to phosphate with polar he ad group that is charged (choline, serine, eth anola mine, inositol, etc)
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- Fatty acid component- 14-24 C in length, usually 1 is saturated and the  other is not (would put a kink in it) - Vary in polar head group, degree of saturation, and length Regulation of Fluidity - Membranes need to balance fluidity to filter - Fluidity is balanced with fatty acid length (increase length to interact  with the one across from it to slow down fluidity) - Phospholipids spin (increase spin, increase fluidity) - Phospholipids also move laterally - Longer phospholipid tails restrict movement - Kinky fatty acids don’t pack as well and increase fluidity (by decreasing  saturation) - Stress proteins (HSP) that bind to membranes when they are too high,  decrease fluidity very quickly Outside is phosphatidyl choline and inside (cytoplasm side) are others  and they do not flip flop Asymmetry causes charge difference (more +  outside and – cytoplasm  Cholesterol Embeds itself in membrane so that hydrocarbon tail fits with fatty acids (90 turn) Fluidity: - Restricts movement of phospholipids - Increase cholesterol, decrease fluidity
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Glycolipids Oligosaccharides (short chain monomer attached to lipid) 3-15 sugars Attach on outside (face out) Most are branched Take in signals and help detect changes outside (signal transduction, outside to inside) Ex myelin Less than 5% of all lipids are glycolipids (associated sugar) Proteins Nerve- less than 25% of membrane is protein (internal membrane will have 80%) Decrease fluidity (restrict movement) Proteins can move (fluid themselves) Can cross entire membrane (transmembrane proteins) - Regions can extend to inside a nd outside of cell (weave b ack and forth) to keep protein in m e m bran e (alpha h elix or b et a she ets are - Makes pores/chann els for molecules to move bec aus e of structure and - Signal transduction Som e proteins don’t cross (peripheral proteins) - On one side or a nother - Hydrophobic and hydrophilic sides keep it in the right orientation
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This note was uploaded on 06/15/2011 for the course BY 330 taught by Professor Watts during the Spring '11 term at University of Alabama at Birmingham.

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Cell Bio Test 3 Notes - Cell Bio Test 3 Notes Lecture 14...

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