Diffusion and Osmosis - 13/11/23 Flashcards
What is diffusion?
The net movement of particles from an area of high concentration to low concentration
What are the 4 factors affecting diffusion?
1) Distance for diffusion
2) Concentration gradient
3) Temperature
4) Surface Area
What kind of process is diffusion?
It’s a passive process - doesn’t use any energy
What is Fick’s Law?
Rate of Diffusion = SA x Conc. Gradient/ Distance
When you want rapid rate of diffusion, what should happen to SA, Conc. Gradient and Distance?
1) SA increases
2) Conc. Gradient increases
3) Distance decreases
In biology, what have many organisms evolved to do?
Many organisms have evolved to maximise rate of diffusion
What is Facilitated Diffusion?
It’s a passive process where particles move from higher to lower concentrations through a transport protein
Why does Facilitated Diffusion require a channel protein?
It requires a channel protein in the cell membrane to transport polar molecules, charged and water soluble molecules across the membrane
Describe and explain the effect of an increase in temperature on the rate of diffusion (3)
1) The molecules gain more kinetic energy
2) This makes them move faster
3) Increases rate of diffusion
What is the definition of Osmosis?
The movement of water molecules from a less negative water potential to a more negative water potential, across a partially permeable membrane
What do we measure water potential in?
kPa
What is the symbol for water potential?
Psi
What is water potential of Pure Water?
0kPa
What happens to water potential as more solutes are added?
The water potential becomes more negative
What does hypotonic mean?
Less negative water potential
