Unit 2 & 3 - Cell Transport (Diffusion, Osmosis, Active Transport) Flashcards
What happens during diffusion?
Molecules move from an area of high concentration to and area of low concentraton.
They move down the concentration gradient
What type of process is diffusion and what does that mean?
Diffusion is a passive process, meaning it doesn’t require energy
Why does diffusion only happen in liquidsB and gases?
Because the particles in these substances are free to move around freely
How do molecules reach equilibrium?
When the molecules have diffused until they are evenly spaced apart
When is diffusion faster?
When:
- The temperature is warmer
- There’s a higher concentration area
- When the diffusion area is smaller
- There’s **more surface area **for diffusion to happen
What is Osmosis?
Osmosis is the diffusion of water molecules from a low concentration solution to a high concentration solution, through a partially-permeable membrane
What is a partially-permeable membrane?
A ppm has holes in it that permit water molecules through but are too small to allow larger molecules through
What sort of membrane are plant and animal cells surrounded by?
Pertially-permeable plasma membrane
What do plant cells have that offers support and protection?
A strong cell wall
Because animal cells dont have cell walls, how do they act differently to the gain and loss of water?
- In dilute solutions, osmosis causes the cell to _swell up and burst _
→This is called lysis
- In concentrated solutions, water loss causes the cells to shrink
→This is called crenation
What is Active Transport
Active transport is a method of transport for substances to get in and out of cells
Why is Active Transport different to Diffusion and Osmosis?
- It requires energy
- It goes against the concentration gradient (low to high)
How is Active Transport used by cells?
To concentrate substances inside cells or remove toxins
