Cell Action!

Introduction: Welcome to the most exciting part of this topic; all of the metabolic processes in the cell. Here you will see pictures of different types of diffusion. These include: facilitated transport, active transport, endocytosis, and exocytosis.

Again, definitions are from “Human Biology” by Mader, Sylvia S.

Facilitated Transport: A molecule is transported at a high rate from an area of higher concentration to lower.

Here is a picture from http://fig.cox.miami.edu/~cmallery/150/memb/c8x16types-transport.jpg

that shows facilitated, or passive, transport. It also has diffusion and active transport.

Active Transport: A molecule is moving from lower to higher concentration. This needs energy to happen.

http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0645.jpg

This website shows the active transport of the sodium-potassium pump.

Endocytosis: A portion of the cell membrane takes in substances and forms a pouch. The membrane pinches off to form an endocytic vesicle in side the cell.

Here is a great picture of endocytosis from

http://cache.eb.com/eb/image?id=4946&rendTypeId=4

Exocystosis: A vesicle fuses with the plasma membrane as secretion happens.

Here is a simple visual of exocytosis from http://www.linkpublishing.com/exocytosis5.jpg

Conclusion: For a little bit more information, diffusion is the random movement of molecules from high to low concentration. Osmosis is the diffusion of water across the cell membrane. Now that we have seen the cell in action, it is time to move on. Remember, back up top, the organization of a bunch of cells make a tissue? Well, we have a talked A BUNCH about cells, so now to tissues.