Cellular transport

• All cells have a cell membrane
• It controls what enters and exits the cell to maintain an internal balance called homeostasis
• Provides protection and support for the cell
• Structure of cell membrane = lipid bilayer
• Phosphate head is polar (water loving)
• Fatty acid chains non-polar (water fearing)
• Proteins are embedded in membrane
• Have ppores which are slectivley permeable: allows some molecules in and keeps other mollecules out.

Passive transport

• Cell doesn't use energy (e.g diffusion, facilitated diffusion, osmosis)
• Molecules move randomly
• Molecules spread out from a high concenttration to a low concentration

Diffusion

• Random movement of particles from high to low concentration
• Diffusion continues untill all molecules are evenly spread and equilibrium is reached. (NOTE: molecules will still move, just evenly)

Facilitated diffusion

• Diffusion of specific particles through transport proteins found in the membrane.
• Transport larger or charged molecules

Osmosis

• Diffusion of water through a partial permeable membrane.
• From high water potential to a low water potential

Active transport

• Uses energy
• movement from a low concentration to a high concentration

Protein pumps

• Transport proteins that require energy to do work (e.g sodium/potassium pumps are important in nerve responses)

Endocytosis

• Taking bulky material into a cell
• In-folds around the "food" particle and forms food vacuole and digests food.

Exocytosis

• Forces material out of cell in bulk. Cell changes shape which requires energy.

Hypotonic: the solution has a lower concentration of the solutes and a higher concentration of water than inside the cell. (Low solute; high water)

RESULT: Water moves from the solution to inside the cell; cell swell and bursts (cytolysis)

Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water inside the cell (High solute;low water)

RESULT:Wter moves from inside the cell into solution; cell shrinks (plasmolysis)

Isotonic:The concentration of solutes in the solution is equal to the concentration of solutes inside the cell

RESULT: Water moves equally in both direction and cell remains sam size. (Dynamic equilibrium)