Biological Membranes Flashcards
What is the role of the plasma membrane
Separates cell components from surroundings
Regulates material transport
Contains enzymes used in reactions
Cell signalling
Site of chemical reactions
What is the role of organelle membranes
Allows each organelle to perform a specific function (compartmentalisation)
Site for reactions
some form vesicles when pinched off (RER, Golgi apparatus)
What is the name of the model displaying the plasma membrane
Fluid Mosaic Model
What is the role of Cholesterol in the Plasma membrane
Maintains fluidity of the membrane
What is the role of Carrier and Channel protiens
To move solutes in and out of the cell that are to large to move in via simple diffusion
Use Active transport and facilitated diffusion
What is the name of the bilayer that makes up the membrane
Phospholipid Bilayer
How does the Myelin Sheath membrane on a neurone differ to that of a regular cell?
The sheath has multiple layers of membrane cause by flattened cells
The membrane is about 20% protein and 76% lipid to provide electrical insulation
What types of molecules can diffuse through the phospholipid bilayer
Some small molecules like Oxygen and CO2
Lipid soluble molecules even if they are larger (e.g steroid hormones)
How is the concentration gradient maintained when CO2 and Oxygen are constantly diffusing into plant cells
Oxygen is used up by the mitochondria for respiration in working cells
CO2 diffuses into the palisade mesophyll cells and then the chloroplasts to be used in photosynthesis
What types of molecules require facilitated diffusion
Small Polar molecules
they are unable to pass through the bilayer due to the hydrophobic properties of the fatty acid tails.
What feature of many membranes allows water to move through more rapidly
Aquaporins
