Movement in and out of cells TOPIC 1 Flashcards
Define diffusion
Diffusion is the net movement of particles spreading out from an area of higher concentration to an area of lower concertation, until equilibrium is reached
can diffusion happen in solids
no, it only happens in solutions and gases
what is the conenratation gradient
the difference in concertration
how can you make diffusion happen quicker
- bigger concentration gradient
- higher temperature
- shorter distance to travel
- larger surface area to volume ratio
- larger surface area
why does heating cause diffusion to happen quicker
the particles gain more energy, so they move faster
what type of process is diffusion
it is a passive process
what is a passive process
it means that it requires no energy input
how have multicellular animals adapted to increase diffusion
Villi in the small intestine increases the surface area
why does increasing the surface area speed up diffusion
because it means that more molecules can cross the membrane in any given period of time
What are the ways molecules transport
- diffusion
- osmosis
- active transport
what type of molecules can diffuse
small molecules like oxygen, larger molecules cannot
how have multicellular plants adapted to increase the rate of diffusion
root hair cells at the tips of the plant roots increase the surface area
why can unicellular organisms diffuse directly into or out of a cell
because they have large surface area to volume ratio
How is the cell membrane adapted for diffusion
it is partially permeable that let some molecules through
is osmosis a passive process
yes
what is an isotonic solution
a solution that has the same solute concentration as another solution
what is a hypertonic solution
a solution that has a higher solute concentration than another solution
what is a hypotonic solution
a solution that has a lower solute concentration than another solution
what is osmosis
the movement of water molecules across a partially permeable membrane from a region of higher water concertation to a region of lower water concertation, until equilibrium reached
what is water concertation
the measure of how concentrated the water is in a solution
if a plant cell is put into a hypertonic solution what will happen to the water in the cells
the water in the cells would leave causing it to die and become plasmorised
what do you call a plant cell where all of the water has left it and it has shrunken
plasmolised
what do you call a plant cell where water has entered it
turgid
what would happen to the water if a plant cell was put into a hypotonic solution
the water outside the cell would move into it
What is active transport
the movement of particles from a region of lower concerntration to a region with higher concerntation against the water gradient, using enrgy from respiration
Is active transport a passive process
no
how do plants use active transport
by pumping in mineral ions because they are present in lower concentrations in the soil than in the root hair cells
how do animals use active transport
by the villi pumping glucose and amino acids into the blood from the gut
what does the surface area : volume ration determine
how easily stuff moves between an organism and its environment
what will the surface area : volume ratio be like for a larger organism
Small
how do you calculate the surface area of an organism
top and bottom areas + four sides areas
how do you calculate the volume of an organism
length x width x height
what organisms need exchange surfaces
multicelluar
how have exchange surfaces adapted to make them more efficient
- thin
- large surface area
- good blood supply
- ventilate
How do the lungs make gas exchange more efficient
- clusters of alveoli
- large surface area
- rich blood supply
why do organisms have exchange surfaces
becuase they neeed a special exchange surface for efficient diffusion due to a smaller surface area : volume ratio so not enough substance can diffuse
How do you calculate % change in mass
% change in mass = (change mass / original mass) x 100
What can you use to investigate osmosis
Potatoes and putting them in different salt solutions
How can you investigate surface area : volume
Using agar and 3 different sized cubes, by placing them in acid the acid will diffuse into the cube removing the pink dye
How is the small intestine adapted to maximise diffusion
- thin lining
- lots of capillaries
- lots of villi
What diffuses out of cells
Urea
How are fish gills adapted for exchange substances
- many gill filaments ~ large surface area
- thin gills
- good blood supply
Give two examples in multicellular animals which have adapted to increase diffuse
- alveoli in the lungs: larger surface area for oxygen to diffuse faster
- villi in the small intestine: larger surface area for faster diffusion, thin walls for short pathway
