Active+Transport

Active Transport is the process of letting molecules go through the membrane - which is different from the cell wall- and to the place where there is more concentration. However in some cases, cells use this process regardless of the concentration to maintain their regular condition. Just as people pump the air in order to fill their tires, cells do that similarly. Active transport is totally different from diffusion since diffusion does not require energy to move substances.

The picture above shows the concentration of both sides and different types of substances.

The picture above emphasizes the process of cells passing through a membrane.

The picture above simplifies the process of cells being attracted to the area with higer concentration.

Video - http://www.northland.cc.mn.us/biology/BIOLOGY1111/animations/active1.swf

Resources: http://staff.jccc.net/PDECELL/cells/activet.html http://encarta.msn.com/encyclopedia_1741500860/Plasma_Membrane.html#p11 http://www.college-cram.com/study/biology/presentations/368