Cell Transport

Diffusion

The net movement of particles from an area of high concentration to an area of low concentration

Is energy used in diffusion?

No (passive process)

Example of diffusion

Oxygen moving into the blood from the lungs: Carbon Dioxide moving out of cells

Factors affecting the rate of diffusion

1. Temperature (higher = faster)

2. Surface Area (larger = faster)

3. Concentration gradient (steeper gradient = faster)

Osmosis

The movement of water molecules across a partially permeable membrane from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution)

Effects on animal cells (osmosis)

too much water cause the swelling and bursting. Two little water causes shrinking.

Effects on plant cells (osmosis)

Too much water makes the cell turgid (firm). Two little water makes the cell flaccid, causing the membrane to pull away from the wall (plasmolysis)

Active transport

The movement of substances from an area of low concentration to an area of high concentration

Does active transport require energy?

Yes (active process), energy is released by the mitochondria.

Example of active transport

Absorption of mineral ions by plant root hair cells: absorption of glucose in the small intestine