passive transport
solute outside the cell is lower than the inside
hypotonic
solute outside and inside are equal
isotonic
small molecules like...... can move in and out freely
water, oxygen, carbon dioxide
what are the 3 types of passive transport?
1. Diffusion 2. Facilitated Diffusion 3. Osmosis
diffusion always occurs down a _______ (areas from high -> low concentration)
concentration gradient
the difference in the concentration of molecules across a space
concentration gradient
water will cross the membrane toward the higher solute concentration until the _______ of both_____ and _____ even out
concentration gradients water and solutes
random movement of particles from an area of high concentration to an area of low concentration
diffusion
the simplest type of passive transport that does not require the cell to use energy is ____
diffusion
when the concentration of the molecules of a substance is the same throughout a space, a state of _____ exists
equilibrium
diffusion continues until all molecules are _______ (equilibrium is reached) molecules will still move around but stay _____ out
evenly spaced spread
to stay alive, a cell must _________________
exchange materials such as food and waste with its environment
diffusion of specific particles through transport proteins found in the membrane
facilitated diffusion
osmosis water moves from areas of ___ concentration to __ low concentration water moves freely through _____ in the membrane
high low pores
molecules diffuse faster at ____ temperatures
higher
cell membranes help organisms maintain ____ by controlling what substances may enter or leave the cell
homeostasis
solute outside the cell is higher than the inside
hypertonic
the activities of a cell depend on the _____ that enter and leave the cell
materials
diffusion occurs when molecules ___________
move randomly away from each other in a liquid or gas
passive transport- cell uses ________ molecules move _____ molecules spread out from an area of ___ concentration to an area of ___ concentration
no energy randomly high low
the movement of substances across the cell membrane without any output of energy
passive transport
large molecules like...... can not move in and out of the cell freely
proteins and carbohydrates
____ molecules diffuse faster
smaller
dissolved substances in a solution _____ is mostly water containing many dissolved solutes
solutes cytosol
facilitated diffusion transport proteins are ____-they "select" only certain molecules to cross the membrane transport __ or ___ molecules
specific larger or charged
the rate of diffusion depends on the _____ ____ and type of ___ that are diffusing
temperature size molecules
diffusion is driven by the _____ the molecules possess. Because of their _____, molecules are in constant motion
kinetic energy
diffusion of water across a semi-permable membrane
osmosis
diffusion of water through a selectively permeable membrane
osmosis
osmosis occurs in response to.......
the concentration of solutes dissolved in water