Ch. 5 Flashcards
Bilayer of phospholipids
2 fatty acids + glycerol
Membrane structure
o membranes are the boundaries of cells, membranes are fluid
membrane function
maintain cell shape, receptors, enzymes, recognition, junctions for attachments, transport, membranes are selectively permeable
diffusion
the tendency for particles to spread evenly in the available space, particles move down concentration gradient
passive diffusion (transport)
when a cell does not have to do work to move molecules across its membrane “no energy added”
osmosis
the passive movement of water from area of high water consideration to an area of low water concentration
tonicity
the ability of a solution to cause a cell to gain or lose water
hypotonic solution
less solutes outside as there is inside the cell (less solute = more water) water moves in
isotonic solution
same amount of water / solute inside the cell as there is water / solute outside the cell (more solute = less water) water moves out
hypertonic solution
more solute outside the cell as there is inside the cell
osmoregulation
the control of water balance, to prevent excessive uptake or loss of water animal cells can regulate solute and water concentration
facilitated diffusion
transport proteins in non-polar membranes help move polar molecules/particles across non-polar region, moving down the concentration gradient still, membrane impermeable to the solute/particle moving
active transport
the cell expends energy to move solutes / particles against the concentration gradient
o toward areas of higher concentration
o requires energy (ATP)
exocytosis
o transporting large molecules outside of the cell
o across the membrane
o fusing with the membrane
endocytosis
o phagocytosis – “cellular eating”
o pinocytosis – “cellular drinking”
o receptor mediated endocytosis – highly selective
o receptor proteins react with specific molecules only
o “coated pit”
