does not require the uses of chemical energy (ATP)

ex. osmosis, diffuseion and facilitated transport

is a physical quantity that describes which direction  and at what rate the pressure changes the most rapidly around a particular location; from an area of high pressure to low pressure area

Greater the surface area of the cell the more efficient the cell can move things in and out of the cell 

                   Surface area = ratio

                      volume   

involved in the passage of molecules through the membrane; has a channel that allows a substance to simply move through the membrane.

eg. moves hydrogen ions

ATP would not be produced without this plow

Cystic firosis

Involved in the passage of molecules through the membrane; combine with a substance (Na⁺ and K⁺ ions across nerve cell membranes) and help move it across the membrane

are glycoproteins; among other functions, these proteins help the body recogniae when it is being invaded by a pathogen and an immunal reaction can occur.

MHC (major histocompatibility complex) forein MHC are attacted by white blood cellsl; why organ transplants can be rejected

a certain shape allows a specific molecule to bind to it; binding of molecules causes proteins to change its shape; brings about a cellular response

ex. insulin for liver storing glucose

Carry out metabolic reactions directly; without the presence of enzymes, some are attached to various membranes of the cell, the cell would never be able to preform metabolic reactions necessary for its proper funceion.