Osmosis & Diffusion

Give an example of a material that needs to ENTER the cell.

-Oxygen molecules -Food molecules

What does a cell have that allows only some materials to travel through the cell membrane?

A selectively permeable membrane.

What is active transport?

Active transport is when a material is pushed through the cell membrane inside the cell using a transport protein. This does require cellular energy.

What is diffusion?

Diffusion is when molecules move from an area of higher concentration to one of a lower concentration so it is balanced.

What causes osmosis?

Diffusion.

What causes diffusion?

Molecules constantly bumping into one another, which causes them to push away from each other and move to an area of lower concentration.

What is osmosis?

Osmosis is when water molecules travel across a cell membrane, moving to an area of higher concentration to one of a lower concentration so there is a balanced amount of water inside and outside the cell.

What is passive transport?

Passive transport is when materials pass trough the cell membrane without using any of the cell's energy.

Give an example of a material that needs to EXIT the cell.

Waste materials

What causes active transport?

When a cell needs to let in a substance that has a higher concentration inside the cell than outside, the molecules must be moved in an opposite direction than how they would move for diffusion.