Transport in cells Flashcards
how do particles in liquids and gases move?
what happens due to the particles’ continuous movement in liquids and gases?
continuously
particles will spread themselves evenly throughout a liquid or a gas.
state what is meant by ‘diffusion’:
movement of particles from an area of higher concentration to lower concentration
what is important to state about the movement of particles during diffusion: (2)
particles:
-will move in both directions, but there will be a net movement from high to low concentration
-will end up evenly spread throughout the liquid or gas but will continue to move
describe what is meant by ‘solute’, ‘solvent’ and ‘solution’:
solute: the substance that will be dissolve
solvent: the liquid that the solute will be dissolved in
solution: mixture formed by solute and solvent
what is a concentration gradient?
describe the movement of particles during this process:
-the difference in concentration of a chemical (across a membrane)
-particles will move down a concentration gradient, from a high concentration to a low concentration.
examples of diffusion in biological systems: describe the process in a leaf (2)
palisade and spongy mesophyll
-oxygen moves out of the palisade mesophyll cells by diffusion into spongy mesophyll cells
-carbon dioxide moves into palisade mesophyll cells by diffusion from spongy mesophyll
examples of diffusion in biological systems: describe the process in the lungs (4)
-blood from the body high in carbon dioxide and low in oxygen
-carbon dioxide diffuses from high concentration in blood to low concentration in alveolus
-oxygen diffuses from high concentration in alveolus to low concentration in blood
-blood to the body high in oxygen and low in carbon dioxide
examples of diffusion in biological systems: describe the process in liver cells (3)
-high concentration of urea in liver cells
-low concentration of urea in blood vessel in liver
-urea is filtered from blood by the kidneys
what can the rate of diffusion be affected by? (3)
Concentration gradient,
temperature
Surface area of the cell membrane separating different regions
how does the ‘concentration gradient’ affects the rate of diffusion?
The greater the difference in concentration, the quicker the rate of diffusion
how does temperature affect the rate of diffusion? (2)
The higher the temperature, the more kinetic energy the particles will have,
-so they will move and mix more quickly
how does the ‘Surface area of the cell membrane separating different region’ affect the rate of diffusion?
The greater the surface area, the faster the rate of diffusion
how does diffusion occur in plants?
substances diffuse into and out of the bacterial cell across its surface
how does diffusion occur in multi-cellular organisms?
substances diffuse into the leaves and simple roots over their surface.
how odes a simple organisms need being determined by its volume cause a problem?
As organisms increase in size, their surface area does not increase at the same rate as their volume.