Diffusion Vs. Osmosis

Biology

Definitions

• Diffusion:– Movement of molecules

from a place where there is a large amount (high concentration) to a place where there is none or a smaller amount (low concentration).

• Osmosis:– Diffusion of water across a selectively permeable membrane

Diffusion Diagram

• High Concentration

• Low Concentration

EquilibriumDiffusionBeginning

Osmosis Diagram

• Selectively Permeable Membrane: Some substances can pass through and some cannot.

3 Types of Solutions where OSMOSIS can take place

• 1. ISOTONIC – amounts of water are equal inside and outside of the cell (EQUILIBRIUM)

93%

93 % 93 %

93%

93%

3 Types of Solutions where OSMOSIS can take place

• 2. HYPERTONIC – amount of water inside the cell is greater than outside of the cell. (CELL SHRINKS)

85%

85% 85%

85%

93%

3 Types of Solutions where OSMOSIS can take place

• 3. HYPOTONIC – amount of water inside the cell is less than outside of the cell. (CELL EXPANDS)

98%

98% 98%

98%

93%

Osmosis & Cell Wall

• Cell wall is a rigid membrane, how is it affected by osmosis?