1. Betsy Sanford 7th Grade Life Science
Cell Transport
Betsy Sanford
7th Grade Life Science

2. Cell Transport
Cells need to obtain materials such as food, oxygen and water for growth, development, and repair
Cells need to remove wastes like excess water and carbon dioxide from chemical activities

3. Cell Membrane
Selectively permeable (semi-permeable, porous, has holes)
Allows materials to pass in and out of the cell
Helps cell maintain internal balance (homeostasis)
Fluid Mosaic Model

7. Passive Transport No energy needed
Happens automatically due to the natural motion of molecules
Molecules move from high concentrations to low concentrations

8. Passive Transport
Moving toward equal distribution of molecules in a space
Molecules will move until the available space is evenly filled (balanced)
2 types: diffusion and osmosis

11. Diffusion Any type of molecule (solid, liquid, gas)
Molecules move from areas of high density to areas of low density
Example: the molecules of the spilled perfume spreading throughout a room
BrainPOP – Diffusion

14. Osmosis
Always and only the movement of water molecules across a cell membrane
Water may be moving into the cell or out of the cell to achieve balance with the surrounding environment

15. Osmosis in Red Blood Cells
1. Distilled (pure) water on the outside. Cells are not pure water. Water will move into the cell until the cell bursts.
2. Normal red blood cells have a balance of water on the inside with the environment on the outside.
3. When red blood cells are placed in salt water, water will exit the cell to balance with the environment. Cells will shrink.

19. Active Transport Energy is needed to move molecules
Molecules are being moved to areas that are already concentrated
Like trying to add more to an overstuffed suitcase
2 types: endocytosis and exocytosis

21. Endocytosis The use of energy to move materials into the cell
Endo = enter

25. Exocytosis The use of energy to move materials out of the cell
Exo = exit

30. Cell Transport BrainPOP – Passive Transport
BrainPOP - Active Transport
Amoeba Sisters’ Cell Transport