Cell Membrane Transportation How do cells transport ions, materials, and solutes?

Solutes 1. A solute is anything that can be dissolved or mixed with water. Examples: Salt Sugar

Cell Membrane Transportation Mechanics There are four components contributing to solutes traveling through cell membranes 2. Energy Lipid Bilayer Proteins Osmotic Pressure

Lipid Bilayer Thin elastic structure 7.5-10 nanometers thick Cytoplasm Extracellular Fluid Thin elastic structure 7.5-10 nanometers thick Sheet of phospholipids and cholesterol, with some proteins

Lipid Bilayer - Diagram

Parts of the Membrane 3. Phospholipids- form the hydrophobic barrier around the cell Proteins- act as channels to let stuff in Antigen/ Marker- act as cell “name tags”

Lipid Bilayer - Permeability 4. Permeability- The ability to travel through the cell membrane 5. Selectively Permeable – membrane is specific about what does/doesn’t enter

Lipid BiLayer Some molecules easily cross cell membranes using their motion and no additional energy Water, oxygen, carbon dioxide Ions, larger polar molecules, and larger molecules (some proteins) cannot easily cross membrane and need energy to do make the journey

Diffusion 6. Diffusion- Movement of molecules across a membrane 7. Passive process – no energy required 8. Molecules always move from higher to lower concentrations (down concentration gradient) Movement until equal concentrations exist Larger molecules move more slowly

Diffusion Diffusion Animation

Factors Affecting Diffusion 9. Molecule size & Concentration gradient

Osmosis 10. Osmosis- The diffusion of water 11.

Osmosis- environments 12. Isotonic- neither cell nor solution gain/lose water 13. Hypotonic – causes net flow of water into cell 14. Hypertonic – causes net flow of water out of cell

Osmosis 15. 16. 17.

Active Transport - Definition 18. Active Transport- Molecules move against concentration gradient and Energy is required

Active Transport - Examples 19. Endocytosis – taking material into the cell & Exocytosis – taking material out of the cell

Active Transport - Endocytosis Low Density Lipoproteins (LDL) being brought into cellular lysosomes

Active Transport - Exocytosis Insulin granule being removed from the pancreas

Conclusion There are two main types of Diffusion Passive Transport- which requires no energy- Osmosis is an example of Passive Transport Active Transport- requires energy, makes solutes go against their concentration gradients.