Surrounds cell contents
Made of lipids and proteins
Plasma membrane/cell membrane
Lipids in a cell membrane, arranged in a bilayer with polar heads on outside and non-polar tails on inside
Amphipathic phospholipids
Water loving
Polar heads, comprising inner and outer faces of the cell membrane
Hydrophilic
Water hating
Two layers of non-polar tails facing each other to form the core of the cell membrane
Hydrophobic
Hydro
Spaces between the tails to reduce solidification during cold
Stabilize the head during elevated temperatures
Cholesterol
Span across the lipid bilayer firmly bound within the membrane some we’ve back-and-forth several times through the membrane
Integral trans membrane proteins
Only on the inner layer or outer surface of the membrane can attach to expose regions of integral protein
Peripheral proteins
Certain materials can pass through cell membranes and only one direction nutrients go in waste goes out
Selective permeability
Difference in concentration (quantity) of a physical value between two area areas
Gradient
Three methods by which particles cross selectively permeable cell
One. Diffusion
Two. Active transport.
Three. Endocytosis or exocytosis.
Net movement of small molecules from high concentration on one side to low concentration on the other side of a membrane
Simple diffusion
Difference between area of high concentration to lower
Eliminated when molecules are equally distributed throughout the solution
Concentration gradient
Another name for diffusion because more energy is released than required
Passive transport
Diffusion of larger, lipid insoluble molecules across a membrane via channel mediated or carrier mediated diffusion
Facilitated diffusion
Small water, soluble molecules use a channel to diffuse through the membrane
Channel mediated diffusion
Osmosis of water occurs through special channel
Aquaporins
Insta group carrier protein, for a certain molecule temporarily binds to the molecule and then releases it to the
For molecules, too large to fit through a channel
Carrier mediated diffusion
Net movement of water across a semipermeable membrane from an area of lower solute concentration to higher solute concentration
Osmosis
Force which water moves into a solution, resulting from the solute concentration
Osmotic pressure
The amount of force needed to stop oy
Hydrostatic pressure
Capacity of an extra cellular solution to make water move into or out of a cell changing its cellular volume via osmosis
Tonicity
Greater concentration of solutes than the inside of the cell causes water to leave the cell resulting in cell shrinkage
Hypertonic
Lower solution concentration than that inside of the cell water moves into the cell, causing the cell to burst
Hypotonic
Solutions that have the same number of solutes
Isotonic
