Cell transport Flashcards
Define ‘diffusion’.
Net movement of particles from an area of high to low concentration (down concentration gradient)
What does it mean by ‘net movement’?
Overall movement: particles can move in any direction, but generally speaking, most of the particles are moving in one particular direction, hence ‘net’ movement
State three factors that affect the rate of diffusion.
Concentration gradient, temperature, surface area
How does concentration difference affect the rate of diffusion?
Higher conc difference/Steeper conc gradient –> faster diffusion
Explain why a higher temperature results in faster diffusion.
More kinetic energy, particles move around more
Name a substance that diffuses into our cells for use.
Oxygen, glucose
Name a substance that diffuses out of our cells to be removed.
Carbon dioxide, urea
Name a structure in the body that is adapted to increase diffusion rate.
Alveoli, villi
Define ‘osmosis’.
Net movement of water molecules down the water concentration gradient through a partially permeable membrane
Define ‘dilute’.
A solution with a high water conc, but low solute conc
Define ‘concentrated’.
A solution with a low water conc, but high solute conc
What are partially permeable membranes?
Membranes that only allow some types of substances to pass through
What is an isotonic solution?
A solution with the same solute conc as the cell
What is a hypertonic solution?
A solution with a higher solute conc than the cell
What is a hypotonic solution?
A solution with a lower solute conc than the cell
