Created by Evian Chai
over 4 years ago
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Question | Answer |
What are 3 essential features of membranes? | 1) Phospholipid Bilayer - Hydrophillic (Polar phosphate heads) - Hydrophobic (Non-polar hydrocarbon chains) 2) Proteins 3) Cholesterol - Essential for plasma membrane function |
What does cholesterol do in the membrane? | Provides structure/rigidity |
What are the 3 types of proteins in the membrane by location? | 1. Integral proteins - imbedded in lipid bilayer, spans membrane 2. Peripheral proteins - attached to membrane via ionic interactions w integral protein/phospholipid heads 3. Anchored membranes - anchored by covalently bound fatty acids |
What are 5 types of membrane proteins by type? | 1. Structural (actin) - cell to cell contact, cytoskeleton organisation 2. Receptors (insulin, glucagon) - signal transduction/recognition 3. Ion channels (Na/K, Ach) - maintain gradient, transmission 4. Transporters (glucose, glutamate) - import/export substances 5. Enzymes (adenylyl cyclase) - catalyst |
What are the four functions of lipids? | 1. Storage of energy via triglycerides 2. Precursors to vitamins/steroids 3. Bile acids 4. Membrane structure (phospholipids) |
What is the structure of a phospholipid? | 1. Polar head group attached to a phosphate head (hydrophilic) 2. Phosphate group attached to glycerol backbone 3. Two fatty acids linked to glycerol |
What links the two fatty acids on a phospholipid to the glycerol backbone? | An ester bond |
Saturated fatty acids have how many double bonds? How does this impact Vanderwaals and melting point? | 0 double bonds Strongest Vanderwaals, high melting point |
What are three common fatty saturated acids? | - Palmitic acid (P) - Myristic acid (M) - Stearic acid (S) |
Mono unsaturated fatty acids have how many double bonds? How does this impact Vanderwaals and melting point? | 1 Weaker Vanderwaals, lower MP |
Oleic acid is what kind of fatty acid? | Monounsaturated |
Poly unsaturated fatty acids have how many double bonds? How does this impact Vanderwaals and melting point? | 2+ Weakest Vanderwaals, low melting point |
Arachidonic acid (synthesized from lionlenic acid) is what kind of fatty acid? | Polyunsaturated |
What are the three essential fatty acids? (all poly unsaturated) What does deficiency lead to? | 1. Linoleic acid 2. Linolenic acid 3. Arachidonic acid Deficiency leads to dermatitis, hair loss, impaired wound healing |
What factors increase membrane fluidity? | 1. # of unsaturated fats - increased=more double bonds=weaker bonds=more fluidity 2, Cis fatty acids - cis fatty acids more fluid bc bonds all lined up 3. Lower cholesterol |
What is cirrhosis in a cell? What does it lead to? | Impaired membrane fluidity due to too much cholesterol Alters cell shape so RBC cannot deliver oxygen, leading to anemia |
What are 4 examples of groups that can be attached to phosphate to form the phosphate group on a phospholipid? | - Choline - Serine - Ethanolamine - Inositol |
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