Cellular Transport

Cellular Transport? Sounds like something off of a Syfi movie, doesn't it? But this ladies and gentlemen, is real!

There are four different types of Cellular Transport: diffusion, osmosis, facilitated diffusion, and active transport. The purpose for these things is so that a cell can keep sustaining life through all that it does.

Diffusion: Diffusion is when a cell moves molecules from an area of high density to lower density in order to keep a natural balance.

Osmosis: Osmosis is where water diffuses from an area of higher concentration to lower concentration until an equilibrium is reached. 

Facilitated Diffusion: Facilitated Diffusion helps different substances to cross the membrane of a cell through special transport proteins. This is because they cannot pass through the membrane on their own like substances that use Osmosis.

Diffusion, Osmosis, and Facilitated Diffusion are all considered Passive Transport. Passive transport does not require using metabolic energy in order to move things around. The substances always move DOWN, as in always to a less dense or less concentrated area.
Example: An example of passive transport would be where there is a high concentration of oxygen outside the cell and a lower concentration of oxygen inside the cell, there for the oxygen seeps through the lipid bilayer in order to oxygenate the cell.

Active Transport: Active Transport uses energy to move materials or substances UP to a more concentrated area where they would not normally be put but happen to be needed in order to keep a cell running. 
Example: An example of active transport is where the membrane of the cell is pumping ions in and out of the membrane in order go get it to transmit electrical pulses.

How can there be Active and Passive Transport if they both do the opposite things? 

Active and Passive Transport are both total opposites when it comes to how they do their jobs. They work against what the other does. But the cell needs both in order to keep working correctly or else it would either   take on too much of something, let go of too much of another, or even quit working. 

Why does Transport matter? If cells quit working because they do not have what they need then what ever they make up will quit working as well because it cannot get what it needs such as nutrition and energy in order to survive.