B3 - Movement into and out of cells Flashcards
What is DIFFUSION? [2]
The net (overall) movement of particles from a region of their higher concentration to a region of their lower concentration as a result of their random movement.
What does PASSIVE PROCESS mean and is diffusion a passive process? [2]
- It means it does NOT require energy
- Yes
What are 4 factors that affect the rate of diffusion? [4]
- Diffusion distance
- Concentration gradient
- Surface area
- Temperature
How does the diffusion distance affect the rate of diffusion? [1]
- The shorter distance the faster the rate of diffusion as it takes less time to travel a short distance
How does the concentration gradient affect the rate of diffusion? [1]
- The greater the difference in concentration between two regions, the faster the net movement of particles and so the faster the rate of diffusion
- The steeper the concentration gradient the faster.
How does the surface area affect the rate of diffusion? [1]
- The greater the surface area that the particles have to diffuse across, the faster the rate of diffusion.
- More space for diffusion and more particles can move in a given period of time so faster diffusion rate.
How does the temperature affect the rate of diffusion? [1]
- The higher the temperature the more KINETIC ENERGY the particles have so the faster the rate of diffusion.
What is OSMOSIS? [2]
The movement of WATER from a higher water potential to a lower water potential across a partially permeable membrane.
What does a partially permeable membrane mean? [1]
A selective membrane which only allows certain particles to pass through.
What is osmosis all about? [1]
WATER!!
When animal cells take in water by osmosis what can happen? [2]
- They swell and burst
- This is because no cell walls
- This is called LYSIS
What happens to plant cells when they take in water by osmosis? [1]
They become FIRM or TURGID
What is TURGOR PRESSURE? [1]
When the pressure inside the cell increases.
What happens to plant cells when they lose water by osmosis? [1]
- They become SOFT or FLACCID
- The plant WILTS
What is a PLASMOLYSED CELL? [1]
When the cell contents collapse away from the cell wall.
When animal cells lose water by osmosis what can happen? [2]
- Become crinkled
- This is called CRENATED CELL
What is ACTIVE TRANSPORT? [2]
The movement of substances from an area of low concentration to an area of high concentration.
In active transport are the particles moving up or down the concentration gradient? What does this mean? [2]
- Moving UP the concentration gradient
- This means it requires ENERGY
Why does active transport require carrier proteins? [1]
Requires carrier proteins in the cell membrane to get substances across the membrane.
In what form of energy does active transport require? [1]
ATP
What do cells that carry out a lot of active transport contain lots of? [1]
Mitochondria
