Membranes Flashcards
What are the 7 structures of a membrane?
Phospholipid bi-layer, carrier proteins, glycolipids, integral proteins, cholesterol, channel protein, glycoprotein
What are phospholipids made of?
Hydrophobic fatty acid tail
Hydrophilic phosphate head
What are glycolipids?
Phosphate with attached carbohydrate, that are for cell signalling and cell-cell recognition. They also stabilise membrane structure
What are carrier proteins?
Permits the passage of specific molecules by facilitated diffusion or active transport
What are channel proteins?
Form a pore through the hydrophobic interior of the membrane to enable water soluble molecules pass by facilitated diffusion.
What are glycoproteins (receptor proteins)?
They are proteins with attached carbohydrate
They help with membrane stability
Cell to cell recognition to prevent the body’s immune system from attacking the cell.
Cell signalling, acting as receptors for hormones and neurotransmitters
What are cholesterol?
Packing molecule that interacts with the phospholipids to regulate membrane consistency, keeping it firm but fluid
What are the 4 functions of a cell membrane?
Physical barrier that seperate intracellular fluid from extracellular fluid
Regulation of the passage of materials
Sensitivity
Support
Why is the cell membrane a physical barrier?
As it separates the cytoplasm from extracellular fluid, as the composition of the cytoplasm and extracellular fluid are very different
How does the cell membrane regulate the passage of materials?
Controls the entry of ions and nutrients, removal of wastes and the release of secretions
Why is the cell membrane sensitive?
As the membrane is the first part of the cell affected by any changes in the environment especially receptors that are sensitive to particular molecules
Why does the cell membrane support the cell?
As the internal part is attached to microfilaments of the cell’s cytoskeleton.
They also support the connections between membranes of adjacent cells which support the whole tissue
