Plasma Membranes
- Created by: Becky2121
- Created on: 13-01-17 09:35
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- Plasma Membranes
- Structure
- Proteins
- Intrinsic
- Embedded through both layers of the bilayer
- EXAMPLES: Glycolipds + Glycoproteins
- Channel Proteins
- Used in passive movement
- Carrier Proteins
- Both passive diffusion and active transport
- Extrinsic
- Through one layer of the bilayer
- Intrinsic
- Cholestrol
- Adds fluidity and stabillity
- Proteins
- Affecting Factors
- Temperature
- Increase = phospholipids move more
- Causes the membrane to be more fluid and eventually lose its structure
- Results in increased permeability
- Due to gaps in the membrane
- Results in increased permeability
- Causes the membrane to be more fluid and eventually lose its structure
- Increase = proteins denature so membrane permeability is affected
- Increase = phospholipids move more
- Solvents
- Organic solvents
- Dissolve the membrane so disrupts the cell
- Water
- Keeps bilayer intact
- Non-polar solutions
- Example: alcohol
- Enters the cell membrane and causes it to become more fluid + more permeable
- Enters the cell membrane and causes it to become more fluid + more permeable
- Example: alcohol
- Organic solvents
- Temperature
- How substances get in and out
- Diffusion
- Facilitated diffusion
- Use a channel protein
- Different as it's DOWN conc gradient and doesn't use energy
- Active transport
- From low to high conc gradient
- Uses metabolic energy from respiration + a carrier protein
- Active transport
- Down concentration gradient (high to low)
- Down concentration gradient (high to low)
- Facilitated diffusion
- Active transport
- From low to high conc gradient
- Uses metabolic energy from respiration + a carrier protein
- Osmosis
- Movement of water particles across a partially permeable membrane
- Water potential
- How much water is in a solution therefore how concentrated it is
- Put simply: how much water there is compared to solute
- 0 is the highest water potential - comes from pure water
- The more concentrated a solution is (less water there is) the more negative the water potential will be
- How much water is in a solution therefore how concentrated it is
- Diffusion
- Structure
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