Notes

cells are small because the small size of cells relates to the need to exchange materials across the plasma membrane
it is efficient because it is easier to get things in and out with a greater surface area
the microscopic size ofd most cells provides a larger surface are to volume ratio

the plasma membrane is a phsopholipid bi-layer with embedded proteins, it has proteins within the layers

surface area to volume ratio :
large cells have more surface area than small cells, but they have a much smaller surface area relative to their volume than small cells

the plasma membrane forms a flexible boundary between the living cells and its surroundings
it controls the traffic of molecules across it, it manages what comes and goes
it is very thin
the structure of the plasma membrane correlates with the function of the plasma membrane

a phospholipid has a negatively charged phosphate group head that is hydrophilic and two non polar fatty acid tails that are hydrophobic
they group together to form a phospholipid bi-layer in aqueous solutions- with proteins floating around
int he protein, the hydrophilic regions are on the exterior and the hydrophobic regions are in the interior