Cell TransportMoving Materials Into and Out of the Cell

Transport through the cell membraneExtracellular fluid ~ The fluid that surrounds

cells. (Interstitial fluid)Intracellular fluid ~ The fluid inside of a cell.

(Cytosol)

Plasma MembraneRegulates what enters and leaves the cell and

also provides protection and support.

Phospholipid bilayer

Plasma MembraneSemi-permeable or selectively permeable

Proteins – channels and pumps that help to move material across the cell membrane.

Carbohydrates – act like chemical identification cards

SolutionSolvent – substance that contains

substances; responsible for doing the dissolving

Solute – substance dissolved in the solvent

Ex: salt water Salt = solute water = solvent

ConcentrationCytoplasm contains a solution of may

different substances in water

Amount of substances vs amount of water

Concentration gradient – drives diffusion and osmosis

Hypotonic, Hypertonic, IsotonicHypotonic – lower concentration of solutes

Hypertonic – higher concentration of solutes

Isotonic – concentration is the same

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Isotonic solution ~ The concentration of dissolved salts in the intracelluar fluid is the same as it is in the extracellular fluid.

Note that normal red blood cells look a bit like Cheerios. They are round and flat with a dent in

the middle.

Hypertonic solution ~ The concentration of dissolved materials is greater in the

extracellular fluid than it is in the intracellular fluid.

Plasmolysis ~ Cell shriveling due to a decrease in internal pressure.

Hypotonic solution ~ The concentration of dissolved materials in the intracellular

fluids is greater than that in the extracellular fluid.

Cytolysis ~ Cell bursting due to internal pressure.

Dynamic equilibriumThe point at which concentrations of a

molecule or compound is equal both inside and outside.

Passive TransportPassive transport is the movement of

materials through the cell membrane that does not require the use of energy.Diffusion ~ The movement of particles from an

area of high concentration to low concentrationOsmosis ~ The diffusion of water through a

semi-permeable membrane. In the case of cells, this will be the cell membrane.

Passive DiffusionMovement of substances is through the cell

membrane from a high concentration to low concentration

Osmosis is a type of passive diffusion where water molecules across the cell membrane

Facilitated DiffusionSubstances cross the cell membrane through

protein channels (specifically designed for that substance)

No energy is used

http://www.youtube.com/watch?v=AYNwynwaALo

Active TransportMovement of substances into and out of the

cell using energy

Protein pumps are necessary; changes in protein shapes is vital for this to occur

Active TransportRequires the use of cell energy (ATP)

Endocytosis: process of taking material into the cell by folding of the cell membrane.Phagocytosis: “cell eating”Pinocytosis: cell takes in liquid from outside

the cell

Active TransportExocytosis: release of materials from the cell

Membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell

Videos!!Plasma Membrane:

http://www.youtube.com/watch?v=owEgqrq51zY&feature=related

Facilitated diffusion: http://www.youtube.com/watch?v=s0p1

ztrbXPY&NR=1Active Transport:

http://www.youtube.com/watch?v=STzOiRqzzL4