transport of materials
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Transport of Materials. Passive Transport. Passive Transport. Movement of materials that does not require energy from the cell. Cell membranes are selectively permeable Allows only certain materials to pass through Particles move across a concentration gradient - PowerPoint PPT PresentationTRANSCRIPT
PASSIVE TRANSPORT Movement of materials that does not require
energy from the cell.
Cell membranes are selectively permeable Allows only certain materials to pass through
Particles move across a concentration gradient Move from an area of high concentration to an
area of low concentration.
SIMPLE DIFFUSION Movement of small particles directly through
the plasma membrane
Speed of diffusion depends on Temperature
Faster at higher temperatures Difference in concentrations
Faster with greater difference
Molecules move until dynamic equilibrium is reached State of balance where particles are equal in
concentration in all directions.
FACILITATED DIFFUSION Movement of larger molecules or charged
ions through protein channels Ions are molecules in which the total number of
electrons is not equal to the total number of protons, giving it a net positive or negative charge.
Essential chemicals travel this way glucose, sodium ions, chloride ions
FACILITATED DIFFUSION – CONT’D Pore proteins
Allows passage of small ions across concentration gradient
Carrier Proteins Special protein
gates openand closeto allow passage.
OSMOSIS Diffusion of water
Semi-permeable membrane prevents movement of solute molecules
Water molecules move to even out the concentrations
OSMOSIS CONT’D Osmosis occurs whenever there is a solute
concentration difference
Special terms used to compare solutions Isotonic - two solutions with the same solute
concentration Hypertonic – a solution with a higher solute
concentration Hypotonic – a solution with a lower solute
concentration.