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23 Cards in this Set
- Front
- Back
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List some (7) common membrane lipids.
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•phospholipids - most abundant membrane lipids
•phosphatidylcholine - most common phospholipids •phosphatidylserine - negatively charged •phosphatidylethanolamine •sphingomyelin •cholesterol •glycolipids |
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List some (4) attributes of mobile lipids.
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• rotate
• diffuse laterally • flex fatty acid tails • flip-flop from one side to the other (rare event) |
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What is membrane flexibility?
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Flexibility - ability of the membrane to bend and withstand other deformations.
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What is the purpose for always having Phosphatidylinositol in the cytosolic half of the lipid bilayer?
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Because of its role in cell signaling.
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What is the name of the carbohydrate coat surrounding the lipid bilayer?
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Glycocalyx.
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List some (4) functions of membrane proteins.
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•Transport of molecules across bilayer
•Anchoring •Receptors •Enzymes |
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Give an example of a single-pass transmembrane protein.
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Receptor.
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Give an example of a multi-pass transmembrane protein.
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Aqueous pores.
*Cross the bilayer as curved beta sheets - form a beta barrel with aqueous interior (e.g. porins in mitochondrial membrane and in bacteria). |
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Name the general solvent that can be used to disrupt a bilayer.
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Detergent.
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T/F?
"Protein-attached proteins" are attached through covalent interactions with transmembrane proteins |
False. Non-covalent.
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Name a method used to remove protein attached proteins.
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Salt wash or enzymes.
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T/F?
Lipid-linked proteins are attached through covalent bonds with membrane lipids. |
True.
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What is one of the best studied transmembrane proteins?
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Bacteriorhodopsin.
*A light-activated proton pump extracted from Halobacterium halobium. |
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What is a chromophore?
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A chromophore is a part (or moiety) of a molecule responsible for detecting color.
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T/F?
Phosphatidyl serine is concentrated in the inner (cytoplasmic) half of the bilayer. |
True.
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T/F?
Phosphatidyl choline is concentrated in the outer (extracellular) half of the bilayer. |
True.
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T/F?
Glycolipids are concentrated on the intracellular surface of the bilayer. |
False: Extracellular.
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What is the cell cortex?
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The plasma membrane is supported by a scaffolding composed of a network of filamentous proteins (the cell cortex) attached to the cytoplasmic face of the membrane.
Functions: •physically supports and stabilizes the membrane •determines the shape of the cell |
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What is the RBC cortex composed of?
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*Spectrin (240 & 220 kd fibrillar protein) forms 3-dimensional network associated with the inner surface of the plasma membrane
*Ankyrin (210 kd protein) attaches spectrin to the membrane *Actin (43 kd protein) forms filaments attached to spectrin via an attachment protein |
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What are proteoglycans?
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Glycoproteins that are heavily glycosylated.
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What are lectins?
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Lectins are sugar-binding proteins that are highly specific for their sugar moieties.
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What are Selectins?
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Selectins are a family of cell adhesion molecules (or CAMs).
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What is FRAP?
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Fluorescence recovery after photo-bleaching (FRAP):
1. Labeling of membrane proteins with a fluorescent dye 2. Bleaching of label in a spot with laser light 3. Diffusion of unbleached label into the area 4. Recovery of fluorescence |
