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What are 6 points on the cell membrane?
- Composed of 2 layers (bi-layer).
- Each layer is made up of phospholipids.
- Layers are faced opposite each other.
- The lipid part is hydrophobic (water hating) and faces inwards.
- The phosphate part is hydrophilic (water loving) and faces outwards.
- Throughout the membrane there are proteins, some go right through the bi-layer forming pores and some are just embedded in the surface.
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How many layers is the cell membrane composed of?
2 layers of phospholipids (a bi-layer).
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What is each layer of the cell membrane made up of?
Phospholipids- a phosphate head and lipid tail.
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What way do the layers of the cell membrane face each other ?
The layers are faced opposite each other.
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Is the lipid part that faces inwards hydrophobic or hydrophilic?
Hydrophobic
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Which part of the phospholipid is hydrophilic?
The phosphate part is hydrophilic.
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What forms pores in the cell membrane?
Proteins that go right through the bi-layer form pores.
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What is also present in the cell membrane?
Proteins are embedded in the surface of cell membrane and some go right through the bi-layer that forms pores.
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The phospholipid molecules are made up of what in the cell membrane structure?
A phosphate head and lipid tail.
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What’s another name for the protein channel in a cell membrane?
Pore
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What do you call the double layer of phospholipid molecules?
The membrane
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What are 3 functions of the cell membrane?
- Holds in cell contents
- Controls entry and exit of molecules
- Semi-permeable barrier
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What are 8 points on the functions of the cell membrane?
- Holds in cell contents: giving shape, support (provided by proteins) and protection.
- Controls entry and exit of molecules.
- Semi- permeable barrier.
- Can let small molecules (eg. water by osmosis and oxygen and CO2 by diffusion) through.
- But not large molecules (eg. salt, sugar, protein).
- (Proteins assist in the active transport of materials across the membrane-energy needed.
- Thus, the cell can control the water and salt concentration- osmoregulation.
- Phospholipids affect the fluidity and permeability of the membrane.)
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The shape and support given by the cell membrane is provided by what?
The cell membrane gives shape, support - provided by proteins.
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What does the cell membrane control?
Controls the entry and exit of molecules.
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What type of permeability has the cell membrane?
It is a semi- permeable barrier.
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What does the cell membrane allow / not allow through?
- Can let small molecules through eg. water by osmosis and oxygen and CO2 by diffusion.
- But not large molecules eg. salt, sugar, protein.
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What is an example of small molecules that are allowed through the cell membrane?
- Water by osmosis.
- Oxygen and carbon dioxide by diffusion.
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What is an example of large molecules that aren’t allowed through the cell membrane?
Salt, sugar, protein.
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What do proteins assist with?
Proteins assist in the active transport of materials across the membrane (energy needed).
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What can the cell control?
Because of proteins assisting in the active transport of materials across the membrane, the cell can control the water and salt concentration (osmoregulation).
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What’s another word for control of water and salt concentration?
Osmoregulation
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What do phospholipids affect in the membrane?
Phospholipids affect the fluidity and permeability of the membrane.
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