Fluid Mosaic Model Components
- Created by: Freja
- Created on: 12-04-21 22:27
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- Fluid Mosaic Model
- Extrinsic Proteins
- Present in one side of the bilayer.
- Normally have hydrophilic R-groups on their surface.
- Phospholipid Bilayer
- Has a hydrophilic head, which attracts water and a hydrophobic tail which repels water.
- The phosphate heads sandwich the fatty aids tails, which forms a hydropho-bic core.
- Doesn't allow water-soluble molecules (like ions) through.
- The phosphate heads sandwich the fatty aids tails, which forms a hydropho-bic core.
- Provides a barrier to large polar molecules.
- Fat soluble substances/ very small molecules can pass straight through.
- 2 layers
- Has a hydrophilic head, which attracts water and a hydrophobic tail which repels water.
- Cholestrol
- A type of lipid.
- Positioned between the phospho-lipids and binds to the hydrophobic tails of the phospholipid, causing them to pack more closely together. This makes the membrane less fluid and more rigid.
- Reduces permeability to charged particles.
- Hydrophobic ends interact with tails pulling them together.
- Intrinsic Proteins
- Span the width of membrane (transmem-brane proteins).
- Amino acids with hydrophobic R-groups.
- Channel Proteins
- Provide a hydrophilic channel.
- Allowing passive movement (without ATP) down the concentration gradient.
- For polar molecules/ions down a concentration gradient.
- Carrier Proteins
- Plays a role in passive and active transport into cells.
- They change shape to move substance from one side to the other.
- Glycolipids
- Lipids with attached carbohydrate chains.
- These molecules are cell markers/ antigens and can be recognised by the immune system as self.
- Glycoproteins
- Intrinsic proteins, embedded in the cell-surface membrane.
- Has an attached carbohydrate chains of varying lengths and shapes.
- It the recognition for chemicals
- Plays a role in cell adhesion (when cells join together to form tight junctions in certain tissues) and as receptors for chemical signnals.
- Has receptors for hormones, enzymes etc
- When chemical bind to receptors it elicits a response from the cell- this is cell signalling
- Some drugs act by binding to cell receptors.
- Propsed in 1972
- Protein molecules are scattered throughout the bilayer, like tiles in a mosaic
- Extrinsic Proteins
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