Cell Membranes

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What is the cell surface membrane?
The cell surface membrane is a thin double layer of tightly packed phospholipids that surrounds the cell. Embedded in the double layer are larger protein molecules. Some go through both layers of phospholipids, and some which only go through one.
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Do the cell organelles have the cell surface membrane surrounding them?
Yes, they do.
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What is another name for cell surface membranes?
Plasma Membranes
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What does the membrane do?
The membrane is partially permeable, and therefore only allows some substances through.
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How can substances enter the cell or organelle through the membrane?
The substances can either diffuse into the cell (when the concentration gradient is great enough) or enter the cell through osmosis. For osmosis to occur, there needs to be a greater water potential outside the cell than inside it.
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What limits the substances that can enter the cell/organelle?
The size of the substances diffusing into/out of the cell limits what can diffuse into it. The substance has to be small enough to pass between the phospholipid molecules for it to enter or exit the cell/organelle. Water, oxygen and CO2 can do this.
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For diffusion or osmosis to take place, does the cell need energy?
No, the cell doesn't need energy for these processes to take place, as they will take place passively.
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Card 2

Front

Do the cell organelles have the cell surface membrane surrounding them?

Back

Yes, they do.

Card 3

Front

What is another name for cell surface membranes?

Back

Preview of the front of card 3

Card 4

Front

What does the membrane do?

Back

Preview of the front of card 4

Card 5

Front

How can substances enter the cell or organelle through the membrane?

Back

Preview of the front of card 5
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