Download File osmosis @ diffusion guided notes 6b

Osmosis and Diffusion
Cells have structures that protect their contents from the world outside.
All cells are surrounded by a cell membrane that separates the cell
from the outside environment. The cell membrane is selectively
permeable
Selectively Permeable - some substances can _____________ the
membrane while others _________________________________
Substances can move into and out of a cell be one of ______methods:
1. Diffusion
2. Osmosis
3. Active ________________Diffusion – is the process by which _________________________ of
__________________________ to an area of lower concentration –
diffusion is the main method by which small molecules move across the cell
membrane!
What causes diffusion?
Molecules are always moving and as a result, they bump into each other
(collide). When collisions occur, molecules move push away from one another
and spread out. Eventually, they will spread out evenly throughout the area.
Osmosis – is the diffusion of water molecules through a
_______________________________ – cells cannot function properly
without water, so many cellular processes depend on osmosis
**In osmosis, water molecules move by diffusion from an area of
high concentration (a lot of H2O molecules) to an area of low
concentration (few H2O molecules)**