Cell Membrane Bits And Bobs Flashcards
Fact to do with cell membranes of a certain type (pro or euk) cells?
Eukaryotic cells’ organelles have cell membranes
Type of permeability description of a membrane?
Partially permeable
General introduction of description to cell membranes
They act as a barrier between the cell and its environment
The cell membrane of organelles act as a barrier between the organelle and the cytoplasm
Proportion of lipids, protein and carbohydrates in cell surface membrane?
45% lipid
45% protein
10% carbohydrate
Who proposed the fluid mosaic model and when?
1972
Jonathan Singer and Garth Nicolson
How are proteins positioned in the phospholipid bilayer?
Proteins are scattered throughout the bilayer, they constantly shift and move
How are intrinsic proteins positioned in the bilayer?
They span the width of the membrane (basically they go all the way through so it’s like a straw going through a brick as a passageway)
Where are extrinsic proteins positioned in the bilayer?
Outer or inner surface of the phospholipid bilayer
Talk about carbohydrate groups in the cell surface membrane?
Some extrinsic proteins combine with carbohydrate groups and form glycoproteins. They extend from the cell surface. Along with glycolipids, they both act as chemical receptors of the cell.
What do some proteins on the inner surface of the membrane do?
Attach onto the cytoskeleton to anchor the membrane into place.
Why is the fluidity of the membrane good?
It means that the cell membrane is flexible and the hydrophilic phosphate heads move past each other so the cell membrane can easily change shape. (Ie. When a phagocyte needs to change shape to engulf a pathogen)
Why does the phospholipid bilayer not allow water to pass through it?
Because the hydrophobic tails on the inside don’t allow the water to pass through
What do carrier proteins have that a channel protein doesn’t?
An active site which the chemical being transported must bind to
