Fluid boundaries

Created by: Steff06
Created on: 03-04-16 13:26

What are the role of membranes?

Separating cell contents from the outside environment. Separating cell contents from the cytoplasm. Cell signalling and recognition. Holding components of metabolic pathways in place. Regulating transport of materials in/out of cells.

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Why are all membranes permeable to water?

Water molecules can diffuse through the lipid bilayer. Membranes containing aquaporins are even more permeable.

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Describe the phosphate head and fatty acid tails

The phosphate head is hydrophilic and the 2 fatty acid tails are hydrophobic.

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Describe partially permeable membranes

Partially permeable membranes are permeable to water an some solutes.

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What do the phospholipid molecules rarely do and what gives the bilayer stability?

Molecules rarely 'flip-flop' from one layer to another. Hydrophilic head cannot pass through the hydrophobic region which provides stability.

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Describe the fluid mosaic model

Lipid molecules give fluidity and proteins give it a mosaic appearance.

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What are the features of a fluid mosaic model?

Phosphlipid bilayer forms the basic structure. Protein molecules float in the bilayer, some freely and some bound to other components. Extrinsic proteins partially embedded in bilayer on outside/inside face. Intrinsic proteins spanning the bilayer.

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Other cards in this set

Card 2

Front

Why are all membranes permeable to water?

Back

Water molecules can diffuse through the lipid bilayer. Membranes containing aquaporins are even more permeable.

Card 3

Front

Describe the phosphate head and fatty acid tails

Back

Card 4

Front

Describe partially permeable membranes

Back

Card 5

Front

What do the phospholipid molecules rarely do and what gives the bilayer stability?

Back

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Fluid boundaries