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13 Cards in this Set
- Front
- Back
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Functions of a Plasma Membrane |
a. It isolates the cell's contents from the external environment. b. It regulates the exchange of essential substances c. It allows communication between cells d. Creates attachments within and between cells e. Regulates biochemical reaction |
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Fluid Mosaic Model |
Each membranes consists of a "mosaic" of different proteins that constantly shift and flow within the double layer of phospholipid. |
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Phospholipid Bilayer |
-fluid or flexible aspect of the membrane -phospholipids consist of two parts - the hydrophilic head (Polar) - the hydrophobic tail (non polar) This variation of polar and non polar substances cause the phospholipid tails to face towards each other with the heads facing towards the external environment. - Kinks are created by the double bond in the unsaturated fatty acids, in the tails of the phospholipids determine the fluidity of the membrane - Individual Phospholipids are bonded to one another |
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What can get through the bilayer? |
-water-soluble (polar) substances cannot cross the bilayer -lipid soluble (non polar) and extremely small polar molecules (i.e water) can cross the bilayer Cholesterol stabilizes membranes affecting fluidity and reducing permeability |
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Proteins |
-Proteins are embedded within, or attached to the phospholipid bilayer -many proteins have attached carbohydrate (glycoproteins) on their outer membrane surface |
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5 Types of Membrane Proteins |
1. Receptor Proteins 2. Recognition Proteins 3. Enzymatic Proteins 4. Attachment Proteins 5. Transport Proteins |
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Receptor Proteins |
They trigger cellular responses upon binding of specific molecules, such as hormones, sent by other cells. |
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Recognition Proteins |
They are glycoproteins that serve as identification tags in the surface of a cell. |
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Channel Protein |
A type of transport protein: Form channels whose central pores allow specific ions or water molecules to pass through the membrane. |
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Carrier Proteins |
A type of transport protein: have binding sites that can temporarily attach to specific molecules on one side of the membrane and then move them through the membrane to the other side. |
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Passive Transport |
One of the two forms of transport: diffusion of substances across cell membranes down concentrated gradients -Doesn't require energy |
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Energy Requiring Transport |
One of the two forms of transport: transport the requires the use of cellular energy |
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Gradient |
Difference in concentration (i.e high to low) |
