CELLULAR TRANSPORT

MOLECULAR MOVEMENT

_______________ - the random motion of molecules

_______________ - the random motion of molecules from a region of higher concentration to a region of lower concentration.

_______________ - refers to the difference between the high and low concentrations.

Diffusion rates may be affected by: concentration, temperature, and pressure

DIFFUSION THROUGH A MEMBRANE

Membranes are _______________ - they allow only certain substances to pass through

STRUCTURE OF THE MEMBRANE

The membrane is composed of a _______________ with some proteins embedded in and through. (the Fluid Mosaic Model)

OSMOSIS

_______________ - the diffusion of water through a selectively permeable membrane

The cell has no control over osmosis. Water flows in and out of cells until it reaches _________________ (equal concentrations). Then it continues to flow both directions in equal amounts.

Osmosis depends on the concentration gradient on each side of the membrane which is determined by the concentration of solutes dissolved in the water.

_______________ - have equal concentrations of solutes inside and outside the cell

_______________ - have lower concentrations of solutes outside the cell.

_______________ cause water to flow into the cell.

Plant cells build up pressure called _______________.

Animal cells have no cell walls and may lyse or burst. Other animal cells may pump out excess water through _______________.

Distilled water has no solutes and is therefore _______________ to all cells.

_______________ - have higher concentrations of solutes outside the cell.

Hypertonic solutions cause water to flow _______________ of a cell. (like putting salt on a snail)

Drinking sea water is dangerous to because of this.

_______________ - does not require any energy to be used from the cell.

Osmosis and diffusion take place without cell energy.

_______________uses special protein molecules called carrier molecules to help substances through the membrane from high concentration to low concentration.

_______________ - requires cell energy and moves materials against the concentration gradient. Carrier molecules are used to help substances through the membrane.

BULK TRANSPORT - methods of moving large objects or quantities through the membrane

_______________ - bulk transport into the cell

_______________ - movement of large particles or solids into the cell

_______________ - movement of small particles or liquids into the cell

_______________ - movement of materials out of the cell