1. Passive and Active Transport
Cellular Transport
Passive and Active Transport

2. Multicellular Organisms
Cells work together in order to make the organism function
Groups of cells have specialized function
Need to obtain the necessary molecules to function and release waste products or other molecules
Need to communicate in order to maintain function
Materials need to be able to move into and out of the cell
Cells Tissues Organs Organ Systems

3. It’s All About the Membrane
Lipid bilayer
Found around the cell, the nucleus, vacuoles, mitochondria, and chloroplasts.
Embedded with proteins and strengthened with cholesterol molecules.

4. Cell Membrane
Cells must keep the proper concentration of nutrients and water and eliminate wastes.
The cell membrane is selectively permeable
It will allow some things to pass through, while blocking other things.

5. Proteins in the Cell Membrane
Determine what particles can pass through the membrane
Serve as enzymes
May speed transport
Allow for larger molecules to pass

6. Concentration Gradient
Condition in which the concentrations of particles in 2 given areas are DIFFERENT
Molecules move down or with the concentration gradient, from an area of high concentration to low concentration

7. Dynamic Equilibrium
Condition in which the concentrations of solute particles (solid particles that dissolve in water) in a given area is equal throughout the entire area.
No concentration gradient remains
No NET movement, because movement is equal in all directions
Maintains HOMEOSTASIS for the cell

8. How do you know which way the molecules will travel?
By knowing the concentrations of solute and solvent on the inside and outside of the cell.
Solvent is water
Solute are the molecules dissolved in the water like salt
Solutions on the outside of a cell are described in three ways
Hypertonic
more dissolved solute
Hypotonic solutions
less dissolved solute
Isotonic solutions
the same amount of dissolved solute

9. VISUALIZE HYPERTONIC What will happen?
a) net movement of water _______of cell
b) cell will ________
c) solution is ____________to the cell
Cell with 2% solute, 98% solvent
Beaker with 10% solute, 90% solvent
H2O
H2O
H2O
BEFORE
AFTER

10. VISUALIZE HYPOTONIC What will happen?
a) net movement of water ________ cell
b) cell will ________
c) solution is _____________ to the cell
Cell with 5% solute, 95% solvent
Beaker with 2% solute, 98% solvent
H2O
H2O
H2O
BEFORE
AFTER

11. VISUALIZE ISOTONIC What will happen a) no net movement
Cell with 2% solute concentration, 98% solvent
Beaker = 2% solute, 98% solvent
What will happen
a) no net movement
b) cell won’t change in size
c) solution is _____________ to the cell

12. Transport: Two Main Categories
Passive Transport
No energy required; molecules move down the concentration gradient
Examples:
Diffusion
Osmosis
Facilitated Diffusion
Active Transport
Requires energy; molecules move up the concentration or are too large to move through the membrane without help
Endocytosis and Exocytosis

13. Diffusion
Movement of small molecules from an area of high concentration to an area of low concentration.
O2, CO2

14. Osmosis Diffusion of WATER across a selectively permeable membrane
Occurs until solute concentration is equal on both sides
Water moves to areas where there is more solute

15. Osmosis

16. Facilitated Diffusion
No energy
Use of embedded proteins to help the transport of larger molecules
Amino Acids, Glucose

17. Active Transport Energy is needed to move particles
Uses Carrier Proteins
Change shape with energy to open and close passages across the membrane
Molecules are moving AGAINST the concentration gradient
From low to high concentration

18. Active Transport

19. Active Transport: Vesicles
Movement of MACROMOLECULES into or out of the cell using vesicles
Vesicle bonds with cell membrane and encases or releases material
Starch, Proteins, Lipids
Endocytosis
Into the cell
Exocytosis
Out of the cell

20. Active Transport: Vesicles
Exocytosis
Endocytosis