The Cell Membrane Flashcards
What is a cell membrane?
Surrounds all living cells.
Most important organelle.
Composed of phospholipids, proteins and carbohydrates.
What is the function of a cell membrane?
It controls how substances can move in and out cell.
Its responsible for many other properties of the cell as well.
What is a fluid mosaic structure?
The phospholipids form a thin, flexible sheet while the proteins ‘float’ in the phospolipids sheet like icebergs. and the carbohydrates extend out from the proteins.
What is the significance of the fluid mosaic name?
Because all components can move around and many different components all fit together like a mosaic.
How are the phospholipids arranged?
In a bilayer with their polar, hydrophilic phosphate heads facing out towards water, there non-polar hydrophobic fatty acid tails facing each other in the middle of the bilayer.
What does the hydrophobic layer act as?
A barrier to most molecules, effectively isolating the 2 sides of the membrane.
What do different types of membrane contain?
Phospolipids with different fatty acids, affects the strength and flexibility of the membrane.
What do animal cell membranes contain?
Cholesterol linking the fatty acids together and stabilising/strengthening the membrane.
Where are the proteins located on a membrane?
Usually span from one side of the phospholipid bilayer to the other - integral proteins.
Sit on the surfaces - peripheral proteins.
What do the proteins do on the cell membrane?
Slide around the membrane very quickly and collide with eachother, but can never flip from one side to the other.
Responsible for membranes properties.
What is the structure of the proteins like?
Have a hydrophilic amino acid in contact with water on the outside of membranes.
Hydrophobic amino acid in contact with fatty acid inside the membrane.
Compose about 50% of the mass of the membranes.
