Passive and Active Transport Cellular Transport Passive and Active Transport

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

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.

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.

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

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

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

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

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

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

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

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

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

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

Osmosis

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

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

Active Transport

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

Active Transport: Vesicles Exocytosis Endocytosis