Simple Diffusion: Passive Transport

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Simple diffusion
The simplest form of passive transport is simple diffusion. Simple diffusion does not require the cell to use the energy and does not require carrier protein to carry substances. Only small molecules can pass through simple diffusion such as carbon dioxide or oxygen. Smaller molecules diffuse faster than large molecules. Molecules in simple diffusion moving from high concentration grading to low concentration grading. In the end simple diffusion will cause concentration of the molecules to be the same and they will be in equilibrium. Carbon dioxide,oxygen and lipids enter and leave plasma by simple diffusion.

Facilitated diffusion

Figure 2. Facilitated diffusion

Some molecules can not pass through plasma membrane by …show more content…

Water molecules are usually small enough to pass through plasma membrane and they do not require carrier protein. Osmosis is type of passive transport as it does not require external energy. All cells get water via osmosis and osmosis regulates and balances amount of water in the cells. If water solutes in dissolved water is not equal, there will be a movement in our out of the cell and it depends if cell environment is hypotonic, isotonic or …show more content…

In order for molecules to moves from low concentration grading to high concentration grading it requires energy. ATP(adenosine triphosphate) is a common source of energy in the cell and it is produced by respiration. ATP undergoes a hydrolysis reaction, splitting into ADP and inorganic phosphate, this releases energy so that the solutes can be transported.Also it uses carries proteins, which are similar to facilitated diffusion carrier proteins, however active transport carrier proteins act as pumps. Active transport carrier proteins helps molecules to enter or exit the cell.
Active transport takes place in human body during digestive process. Active transport in the plant cell enables plants roots to absorb mineral ions.

Bulk Transport
The movement of larger molecules such as large proteins,across membrane is called bulk transport.Bulk transport requires energy. There are two types of bulk transport: exocytosis and

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