Membranes Flashcards
Cell membranes and Transport
Why is it described as the fluid mosaic model?
- The protein part of the membrane is unevenly distributed over the inside and outside of the phospholipids looking like mosaic
- The phospholipid part is fluid with its molecules constantly moving.
What are glycoproteins, where are they found and what do they do?
- Glycoproteins are proteins with carbohydrate molecules attached.
- They’re found on the edge of the membrane
- The carbohydrate part is important in cell recognition.
What does the plasma membrane do?
Provides a boundary to the cell cytoplasm, separating it from other cells.
What organelles might the fluid mosaic membrane be found around?
Nucleus, mitochondria, chloroplasts, cell vacuoles, endoplasmic reticulum and Golgi apparatus.
What do the extrinsic proteins do?
Provide structural support, form recognition sites.
What do the intrinsic proteins do?
Include transport proteins for active/ passive transport.
What three factors affect the permeability of a cell membrane?
- Temperature
- Ethanol
- pH
How does temperature affect the permeability of a cell membrane?
If the temperature is too high it can denature the membranes proteins, making it too permeable.
How does pH affect the permeability of a cell membrane?
If pH levels are beyond normal range it can denature the membranes proteins and make it too permeable.
How does ethanol affect the permeability of a cell membrane?
Ethanol dissolves the lipids components of the membrane, making it too permeable.
What is a respiratory inhibitor?
It stops production of ATP and stops respiration.
What do intrinsic proteins include?
Channel and carrier proteins.
Describe the phosphate group in a phospholipid bilayer.
- Has negative charge
- Hydrophilic
Describe the fatty acid tail in a phospholipid bilayer.
- No charge
- Hydrophobic
- Attracts lipids
What does the phospholipid bilayer do?
Acts as a barrier to the passage of molecules and ions in and out a cell.
