Membrane Structure key deets Flashcards
What does each phospholipid molecule consist of?
A hydrophobic tail of two fatty acids and a hydrophilic phosphate head
How are the phospholipids arranged in the cell membrane?
A phospholipid balayer with the hydrophobic fatty acid tails facing inwards away form water and the hydrophilic phosphate head facing towards the water.
Why is the fluid mosaic module described as ‘FLUID?’ And what does this mean?
The phospholipids and mosaic of molecules are constantly moving. This means that is impossible for the barrier to be completely impenetrable.
3 function of intrinsic proteins?
Act as carrier molecules
Act as a passive route for the movement of materials in and out of the cell
Act as enzymes
What do channel proteins and carrier proteins allow to pass through the membrane? ????????
Large molecules and ions
What do receptor proteins do and where are they?
They are on the cell surface membrane
They detect chemicals released by other cells, the chemicals signal for the cell to respond in a certain way (eg. The hormone insulin bind to the receptor proteins on liver cells which tells them to absorb glucose)
What are channel proteins? ??????????
X
What are carrier proteins? ??????
X
What types of molecules does facilitated diffusion transport?
Glucose Ions (Na+ and K+) Amino acids H2O Urea
What types of molecules does simple diffusion transport?
Oxygen
Carbon Dioxide
Oestrogen
Lipids
If something can diffuse through the cell surface membrane by simple diffusion it is ..
Non-polar
If something has to diffuse through the cell surface membrane by facilitated diffusion it is likely to be…
Polar or charged
How do particularly large molecules move through the cell surface membrane?
Endo/exo cytosis
Fatty acid tails are…
NON POLAR
Why do polar things not pass through the phospholipid bilayer?
Because the fatty acid tails are non polar
