Created by Emma Allde
over 8 years ago
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Question | Answer |
Hydrophilic component of a phospholipid | polar head group |
Examples of a polar head group found in phospholipids (4) | serine, choline, ethanolamine, inositol |
Polar head groups of phospholipids attach to what via what | backbone of glycerol through a phosphate group |
Hydrophobic component of a phospholipid | Two fatty acyl side chains |
The two fatty acyl side chains attach to what via what | the glycerol backbone via ester bonds |
Hydrophobic and hydrophilic components make phospholipids what | amphipathic |
Sphingomyelin is what | Component of neural membrane of myelin |
What makes sphingomyelin unique | it lacks a glycerol backbone |
What is the polar head of sphingomyelin | choline |
In sphingomyelin, the phosphate groups attach to what and what | ceramide, a single fatty acyl chain |
Components of a glycerol backbone | CH2, CH, CH2 (across), two O down which attach to the fatty acid chains via an ester bond |
Fully saturated FAs have how many double bonds | none |
Stearic acid | Fully saturated, 18:0 18 carbon atoms in fatty acid, no double bonds |
Palmitic acid | FSFA; 16:0 16 carbon atoms in fatty acid, no double bonds |
Myristic acid | 14:0 14 carbon atoms in fatty acid, no double bonds, SFA |
Mono-unsaturated FA has how many double bonds | One double bond |
Oleic acid | 18:1 18 carbon atoms; 1 double bond |
Poly-unsaturated FA has how many double bonds | several |
Arachidonic acid | 20:4 20 carbon atoms, 4 double bonds |
Delta indicates what | position of double bonded in relation to the carboxyl group counting from the carboxyl terminal |
A kink in a fatty acid represents what | a double bond in a fatty acid |
In cholesterol, what interacts with the polar head groups of the membrane phospholipids and sphingolipids | Hydroxyl group (hydrophilic region) |
The bulky steroid and the hydrocarbon chain are embedded in the_____________ , alongside the ________________ | membrane, nonpolar fatty-acid chain of the other lipids |
Lipid bilayers are described as | asymmetrical |
Phospholipids facing extracellular environment include | Phosphatidylcholine; sphingomyelin |
Phospholipids facing intracellular environment include | Phosphatidylerserine, phosphatidylethanolamine |
Phospholipids are generated where | Within the cell |
Fluidity is what | the ease in which lipid molecules move about in the plane of bilayer |
Fluidity is important in the regulation of what | membrane function (e.g. movement of proteins, signalling, exocytosis) |
Short chain fatty acids do what to fluidity | Reduce the tendency of hydrocarbon chains to interact and hence increase fluidity |
Kinks in unsaturated fatty acids do what to fluidity | Result in less stable van der Waals interactions with other lipids and hence increase fluidity |
High cholesterol does what to fluidity and what is the clinical relevance | Restricts the random movement of polar heads, orders the lipid bilayer and decreases fluidity Alters cell shapes, impairs oxygen transport, destruction of red blood cells and anaemia |
Cholesterol is rich in which regions of plasma membrane | lipid rafts |
When are cholesterols levels abnormal | When content of red blood cells is increased by 20-60% above normal |
Increased cholesterol content of red blood cell membranes is associated with what | severe liver diseases e.g. Cirrhosis |
What are the components of plasma membrane structure | Hydrophobic regions, hydrophilic regions, proteins, glycoprotein, carbohydrate side chain |
Carbohydrate side chain will usually face which direction | out into the extracellular space |
Membrane composition varies according to what | cellular location |
Carbohydrates only found in what of cells | plasma membrane |
Carbohydrates make up how much of the plasma membrane (%) | 8% |
What is the protein lipid ratio of the plasma membrane | 1:1 protein : lipid |
What is the protein lipid ratio of the outer mitochondrial membrane | 1:1 protein : lipid |
What is the protein lipid ratio of the inner mitochondrial membrane | 3:1 protein: lipid ratio |
What is the protein lipid ratio of the nuclear membrane | 3:1 protein: lipid ratio |
What is the most common lipid in the cell membrane | phos/choline |
Integral (intrinsic) proteins are found where | Embedded in lipid bilayer, most span the entire bilayer |
Transmembrane spanning domains of intrinsic proteins are either what or what | alpha helices or beta sheets |
Integral or intrinsic proteins usually serve what function | Channel or transporter |
Anchored proteins are usually found where | anchored to membrane by covalently bound fatty acid (part of a glycolipid) |
Alkaline phosphate is an example of what | an enzyme; anchored protein |
RAS is an example of what | fatty acyl anchored protein signalling protein; relays information from the cell membrane |
Peripheral (extrinsic) proteins are found where | attached to the plasma membrane surface by ionic interactions with integral proteins or with polar head group of phospholipids |
Spectrin is an example of what | peripheral or extrinsic protein structural protein; on the cytoplasmic surface of erythrocytes |
Phospholipase A2 is an example of what | peripheral or extrinsic protein |
Phospholipase A2 is capable of what | cleave fatty acids from phospholipids |
Sites of phospholipase A2 action (3) | (1) Polar head (choline, ethanolomaine, myo-inositol) from phosphate group (PLD) (2) Phosphate group from glycerol backbone (PLC) (3) Remove the fatty acids (PLA1 - usually saturated), (PLA2, usually unsaturated) |
High salt - urea treatment can remove which proteins | peripheral proteins |
Detergent (protein solution) can remove which proteins | peripheral, anchored and integral proteins of the bilayer |
Phospholipase can remove which proteins | peripheral and anchored proteins of the bilayer |
Detergents have a similar structure to what naturally occurring molecule and for what reason | phospholipids with a hydrophilic head and a hydrophobic tail |
Detergent monomers form what | detergent polymer micelles |
Micelles + membrane proteins results in what two components | water-soluble-lipid-detergent complex and water-soluble-lipid-detergent micelles |
Removing detergent and adding phospholipids back to proteins allows you to do what | study your protein of interest and its function |
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