There are different types of movements that cross the cell membrane. One of the transports is a passive transport which consists of movements across the cell membrane which does not require any energy and depends on the permeability of the cell membrane. There are 3 different main roles in passive transport which are called Diffusion, Osmosis and finally facilitated diffusion. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essayThere are different working roles in passive transport, for example in Diffusion the movements of each molecule from the region range from high concentration to low concentration. Another diffusion called "facilitated diffusion" this process does not require ATP but requires the cell membrane for example proteins are called called carrier proteins this transports each molecule across the cell membrane starts from an area of ​​high concentration to a low concentration. Osmosis is a movement of water across a semipermeable membrane towards a solute of very high concentration. In this transport, there is a solution called "hypotonic solution" which contains a high concentration of a solute in relation to the solution inside the cell, for example the “cytoplasm”, a cell is placed in the hypertonic solution, the water will diffuse out of the cell, causing the cell to shrivel. Another solution contains a solution that has a lower salt concentration than the normal cell, the cell will be placed in the hypotonic solution, this means that water will diffuse into the cell causing the cell to swell and this may prevent the cell from exploding . An isotonic solution that has the same concentration of salt as normal cells found in the body and blood, for example when the cell is placed in an isotonic solution the water diffuses in and out of the cell at the same rate, the fluids it is surrounded in the body cell it will be isotonic. In all solutions listed (isotonic, hypotonic, hypertonic) the water will move through the cell and through the special protein coated channels, this means that the total concentration of all dissolved solution is not equal on both sides, this will have a net movement of water molecules in and out of the cell, whether there is a net movement of water in or out of the cell and also in which direction it moves depending on the environmental solutions of the cell which is isotonic, hypotonic or hypertonic. Cell membranes are permeable to water, meaning that the environment the cell will be exposed to can have a dramatic effect on the cell. By moving other substances in and out of the cell, for example “Endocytosis-Endo within the cytotic cell this is a process in which substances, for example proteins, enter the cell without passing through the cell membrane, another process is called “Exocytosis-Exo come out of cytosis the cell is a process where a substance exists from the cell without having to pass through the cell membrane, there are examples of proteins that include enzymes, hormones and antibodies. Finally, there is transport called active transport that requires the cell to use energy that is used to form ATP. The transport act will create a charge gradient in the cell membrane, one of the examples is the mitochondria, the hydrogen ion will pump the hydrogen ions into the intermembrane space which is part of the organelle used to produce ATP. Active transport will keep unwanted ions or molecules that are outside the cell and will be able to.