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24 Cards in this Set
- Front
- Back
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Form barriers between different cellular compartments and define inside from outside
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What is the function of biological membrane?
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40-80% Lipids (Phospholipids, Cholesterol, Glycolipids)
Proteins |
Describe composition of biological membranes?
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Phosphatidylserine (PS)
Phosphatidylcholine (PC) Phosphatidylethanolamine (PE) Sphingomyelin |
What are the MAJOR phospholipids in membranes?
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Phosphatidylinositol (PI)
Phosphatidic Acid (PA) |
What are the MINOR phospholipids in membranes?
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PC
Sphingomyelin |
Which phospholipids are found mainly in OUTER leaflet?
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PE
PS PI |
Which phospholipids are found mainly in INNER leaflet?
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PS
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Which phospholipid is EXCLUSIVELY found in inner leaflet?
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Major component of cell membranes; interdigitates between the inner and outer leaflets
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What is the relative abundance and predominant location of cholesterol?
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Minor component of cell membranes; EXCLUSIVE to outer leaflet
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What is the relative abundance and predominant location of glycolipids?
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Based on ability to extract them from the lipid bilayer
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Based on ability to extract them from the lipid bilayerWhat determines whether the membrane protein is integral or peripheral?
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Protein embedded in lipid bilayer (removed only by disrupting the bilayer; using detergents). Connected to lipid bilayer through covalent bonding to fatty acids or phospholipids
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What is an integral membrane protein?
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Hydrophobic region spanning membrane and hydrophilic region in aqueous environment (cytosol and outside cell)
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Describe single pass integral membrane proteins
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Membrane-spanning region of protein may have polar or charged amino acids (Ex: transporters and ion channels)
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Describe multi pass integral membrane proteins
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Associated by ionic interactions to other membrane proteins or to polar head groups of phospholipids
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What is a peripheral membrane protein?
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Increased cholesterol concentration alters cell membrane and function (spur cells are caused by distorted cholesterol balance)
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What is the significance of cholesterol in advanced Laennec's Cirrhosis?
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Breakdown and reassembly of lipids
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What is meant by lipid turnover?
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Structural rearrangements (exocytosis, endocytosis, fusion)
Repair process (damaged phospholipids by ROS) |
In what circumstances is lipid turnover necessary?
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1. ROS attacks PL (damaging FA)
PLA2 removes damaged FA (result LPL) 1a. FA + CoA form FA-CoA complex 2. LPL + FA-CoA complex form PL + CoA (released for next cycle) |
What is the process of lipid turnover in repairing a damaged phospholipid?
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Hydrolyze phospholipids (cleave ester bonds) producing fatty acids, lysophospholipid, DAG, PA
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What is the function of phospholipases?
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It is a precursor for LEUKOTRIENES, THROMBOXANES, PROSTAGLANDINS (signaling molecules)
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What is the significance of arachidonic acid formed by hydrolyzed phospholipid?
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prostaglandins
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Aspirin (ASA) inhibits the formation of what signaling molecule that triggers inflammation?
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ceramides
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Sphingomyelinase acts on sphingomyelin to produce what signaling molecules?
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G-protein-coupled receptor (GPCR)
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Phospholipase C is activated by what receptor?
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diacylglycerol (DAG)
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Phospholipase C generates what molecule that is used for signal transduction?
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