Active and Passive Cell Transport for HS Freshman Honors Biology
Question
Answer
passive transport
process by which some substances can cross the cell membrane without any input of energy by the cell
diffusion
movement of molecules from an area of higher concentration to an area of lower concentration
concentration gradient
difference in the concentration of molecules across a distance
equilibrium
concentration of molecules is the same throughout the space the molecules occupy
simple diffusion
diffusion across a membrane that only allows certain molecules to pass through the membrane
osmosis
process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration
hypotonic
describes a solution whose solute concentration is lower than the solute concentration inside a cell
hypertonic
describes a solution whose solute concentration is higher than the solute concentration inside a cell
isotonic
describes a solution whose solute concentration is equal to the solute concentration inside a cell
contractile vacuoles
organelles that remove water by collecting the excess water and then contracting to pump out the water
turgor pressure
pressure that water molecules exert against the cell wall
plasmolysis
condition in which cells shrink away from the cell walls, and turgor pressure is lost
cytolysis
condition in which a hypotonic environment causes water to diffuse into the cell, making it swell and eventually burst
facilitated diffusion
type of passive transport in which molecules that cannot readily diffuse through cell membranes are assisted by carrier proteins; thus ~ facilitated
carrier proteins
specific proteins in the membrane that assist the movement of molecules in facilitated diffusion
ion channels
type of membrane protein involved in passive transport - diffusion through ion channels
active transport
movement of materials from an area of lower concentration to an area of higher concentration; UP concentration gradient; REQUIRES cell to expend ENERGY
sodium-potassium pump
transports Na+ ions and K+ ions up their concentration gradients
endocytosis
process by which cells ingest external fluid, macromolecules, and large particles, including other cells
pinocytosis
involves transport of solutes or liquids: DRINK
phagocytosis
movement of large particles or whole cells
phagocytes
cells that allow lysosomes to fuse with the vesicles that contain the ingested bacteria and viruses
vesicle
pouch pinched off from the cell membrane, becoming a membrane bound organelle
exocytosis
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out of the cell
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