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10 Cards in this Set
- Front
- Back
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Are lipids polar or nonpolar?
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Nonpolar: they dissove in organic compounds but not H20
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What are the 3 types of lipids?
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Phospholipids: structural backbone of membranes
Steroids Fats |
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Do lipids form macromolecules?
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No, they aggregate into large complexes though
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What are the 4 types of movements of phospholipids within a membrane?
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Lateral movement within 1 leaflet
Tail flexion: Spinning along axis Flip-flop: 1 leaflet to 2nd leaflet |
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What is the function of lipid fluidity?
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Fluidity of membranes dependent on composition and interaction of phospholipids
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Explain lipid synthesis.
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Made in the cytosol.
Associated with the outer leaflet of organelle - glycolipids of the PM are in the outer leaflet where they serve as receptors for extracellular ligands: Creates symmetry Flipases: proteins that move lipids from outer to inner leaflet Translocases: require ATP hydrolysis to move lipids from 1 leaflet to adjacent leaflet: creates asymmetry |
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What are the characteristics of phospholipids?
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Hydrophobic fatty acid tails: 1 saturated, the other unsaturated: important because allows fluidity and
homeostasis Form micelles in H20 Hydopdrophilic head group: when attaches to P creates a highly water-soluble domain at one end of the molecule |
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Describe cholesterol in the plasma membrane.
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Distributed evenly across the 2 leaflets.
Planar ring structure interferes with lipid tail-tail interactions. Spreads PTT over wider range. Increases stability of membrane Decreases permeability(because phospholipids are moving so quickly at higher temps, cholesterol slows down molecules that could potentially move into membrane) Decreases overall fluidity |
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Explain PTT and its importance.
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Phase transition temperature: the temperature at which movement stops.
Depends on lipids in membrane and the degree of unsaturation |
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Why is fluidity of membranes important?
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Allows changes in cell shape,
allows cells to be dynamic allows movement of the membranes protein function dependent on fluidity of membrane because they go through conformational changes |
