Plasma Membranes Flashcards
What is cytolysis?
When the cell surface membrane cannot stretch much and cannot withstand the increased pressure; which results in the cell bursting.
What is crenation?
Where a cell loses pressure and volume due to the lack of water molecules; the molecules leave the cell using osmosis. This is the opposite of cytolysis.
What is compartmentalisation?
It’s the formation of speedster membrane-bound areas in a cell.
What is the plasma membrane?
The cell surface membrane which separates the cell from its external environment.
What are membranes formed from?
Phospholipid bilayers.
What is the fluid-mosaic model?
A model (by Singer and Nicolson) which extended the idea of how lipid-bilayers have proteins which occupy positions in the membrane.
What year did Singer and Nicolson create the fluid-mosaic model?
1972
What are intrinsic proteins?
Transmembrane proteins that are embedded through both layers of membrane.
What do intrinsic proteins have on their external surfaces?
Amino acids with hydrophobic R-groups.
How are the intrinsic proteins kept in place?
Their external surfaces (amino acids with Hydrophobic R-groups) interacts with the hydrophobic core of the membrane, which keeps them in place.
What are channel proteins?
Intrinsic protein
Provides a hydrophilic channel that allows diffusion of polar molecules and ions down a concentration gradient through membranes.
What is a carrier protein?
Intrinsic protein
Important role with active transport and passive transport into cells.
What are glycoproteins?
Intrinsic proteins
Embedded in the cell-surface membrane with attached carbohydrate chains.
They play a fold in cell adhesion and are receptions for chemical signals.
What is cell adhesion?
When cells join together to form right junctions in certain tissues.
What is hydrostatic pressure?
When the solution in a closed system (such as a cell) results in an increase in pressure.
