Movement in and out of cells Flashcards
Give the definition of diffusion
The net movement of particles from an area of higher concentration to an area of lower concentration.
State the relationship between concentration and speed of diffusion.
The bigger the difference in concentration, the faster the rate of diffusion.
Give the definition of osmosis
Osmosis is the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
Give the definition of a partially permeable membrane.
A membrane with very small holes so that only very small molecules can pass through them. E.G. A cell membrane.
If a cell is short on water, outline how osmosis will help the cell gain water
The solution inside the cell will become more concentrated. This means the solution on the outside of the cell will have more water than the cell on the inside, and so water will move into the cell by osmosis.
Give the definition of active transport.
Active transport is the movement of particles from an area of lower concentration to an area of higher concentration using energy released during respiration.
Give 4 factors that affect the movement of substances.
- Surface area to volume ratio
- Distance
- Temperature
- Concentration Gradient
State how distance affects movement of substances
If substances have a short distance to move, then they will move in and out of cells faster
State how Temperature affect the movement of substances
As the particles in a substance get warmer, they have more energy-so they will move faster. This means as temperature increases, substances move in and out of cells faster.
State how concentration gradient affects the rate of osmosis and diffusion
Substances move in and out of a cell faster if there’s a big difference in concentration between the inside and outside of the cell. If there are more particles on one side, there are more there to move across
