Notes

Homeostasis- balance
all cells must maintain homeostasis which function in a very narrow range of temperatures
Cell membrane is permeable to achieve homeostasis
Selective Permeability- allows certain substances to enter and exit (functions like a window)
Membrane is made of phospholipid bilayer (phospholipid double layer)
Phosphate (head) is attracted to water (Hydrophilic)
lipid (fatty acid tail) is repelled by water (hydrophobic)
Homeostasis is maintained by diffusion, facilitated diffusion, osmosis, active transport
Diffusion- movement of particles from high to low concentration in the cell, helps bring in nutrients and dispose wastes, takes no energy
Facilitated Diffusion- movement of particles across a cell membrane from high to low concentration with the help of membrane proteins, takes no energy
Osmosis- movement of water across a cell membrane from high to low concentration, no energy needed
Passive Transport- goes with concentration gradient, high to low, no energy needed (Examples include diffusion, osmosis, facilitated diffusion)
Active transport- goes against the gradient, low to high, requires ATP (cell energy)
Osmosis occurs when cells are placed in different liquid environments or solutions
Hypotonic- hypo= below (lower solute) 10% salt means carrot will have 90% water
Hypertonic- hyper= above (higher solute) 20% salt means carrot will have 80% water
Isotonic solution- iso= equal (equal amounts of solute) 15% salt means carrot will have 85% water
Membrane Pumps- moves materials opposite to diffusion or against the gradient, active transport
Endocytosis- two types are phagocytosis (solids, phag=eat) and Pinocytosis (liquids, pino=drink)
Exocytosis- expels materials from the cell