Biology Lab 4 Flashcards
How is the steady state of a cell maintained
regulated movement of materials thru cytoplasm, across organelle membranes, and across the plasma membrane
what type of solution is are the cytoplasm and extracellular environment of the cell
aqueous
what is a solvent
a dissolving agent
- ex=water
what is a solute
dissolved substances
are the membranes of organelles and the plasma membrane permeable
they are selectively permeable
selectively permeable
allowing water to freely pass through but not regulating the movement of solutes
what is ATP
adenosine triphosphate
when is ATP used
when the cell actively moves some dissolved substances across membranes
how do molecules move in diffusion
move from area of high concentration to area of lower concentration
what is the energy that dives diffusion
intrinsic kinetic energy in all atoms and molecules
how are some substances able to move passively
ATP is used and only if cell membrane is permeable to those substances
is osmosis a form of diffusion
yes; type of diffusion
what does osmosis specifically move
water through a selectively permeable membrane
- highly concentrated to lower concentration
what causes a difference in the concentration of water in osmosis
if there is an unequal distribution of at least one dissolved substance on either side of a membrane and the membrane is impermeable to that substance
osmolarity
solute concentration expressed as molarity
tonicity
releative concentration of solutions inside and outside a cell that will determine the direction of water flow
- hypertonic
- hypotonic
- isotonic
what kind of solution is hypertonic
solution with greater concentration of solute particles
- water leaves cell
what kind of tonecicity causes a cell to shrivel
hypertonic
what kind of solution is isotonic
solute concentrations are equal
- water coming in = water leaving
what kind of tonicity causes the cell to swell
hypotonic
what kind of solution is hypotonic
solution with lower solute particles
- more water is moving into cell than leaving cell
why are molecules of a liquid or gas constantly in motion
because of the intrinsic kinetic energy in all atoms
what is the driving force of diffusion
intrinsic kinetic energy
what is intrinsic kinetic energy
molecular kinetic energy being passed to larger molecules
Brownian Movement
random motion of particles suspendered in a medium
how does the net flow of water work in cell so freshwater plants and algae in their environment
they are bathed in water containing only dilute concentration of solvents
- water from surrounding environment into the cells
what affects the cells response to solutions of different molarities in plants or algal
presence of a cell wall and a large fluid filled central vacuole
what happens to a plant cell when it is placed in a hypertonic solution
water moves out of the cell
- protoplast shrinks and moves away from cell wall
what is the process called when protoplast shrink and move away from the cell wall
plasmolysis
what happens to a plant when it is placed in a hypotonic solution
water moves into cell and into cell’s central vacuole and the protoplast expands
what is a protoplast
the plant cell exclusive of the cell wall
- the cytoplasm enclosed by plasma membrane
turgor pressure
pressure of the protoplast on the cell wall owing to uptake of water
what happens when there is high turgor pressure
prevent further movement of water into the cell
how does turgor pressure relate to hypertonic conditions
turgor pressure begins to force water through the membrane and out of the cell
in plants, what is needed to for normal activities to take place
amount of water relative to solute concentration in cell must be maintained within a reasonable range
what was one of the objects for part 4.3
find the molarity at which weight of the potato tuber tissue does not change, indicating that there has been no net less or gain of water
