Transport

**__ Cell Transport and Plasma Membrane __**
section created by eshani bhatt

** What is Cell Transport? **
Cell transport is the movement of molecules going in and out of the cell. These movements will effect the way the cell functions. Cell transport is an important factor because it will determine if a cell will live or die.

// To learn about the two types of cell transport, it's helpful to know about **diffusion**. Diffusion is is process by which substances intermingle by the natural movement of their particles. // **Passive Transport**: This is the transport of a substance caused by diffusion. Energy is **not** required for this to take place. **Facilitated Diffusion** is the process of diffusion and is a form of passive transport where molecules diffuse across membranes with the help of transport proteins. **Active Transport:** This is the transport of a substance caused by diffusion. Energy **is** needed for this to take place. The answer is Osmosis! **Osmosis** refers to a process by which molecules of a **solvent** tend to pass through a **semipermeable membrane** from a less concentrated area of the **solution** to a highly concentrated area in the solution. This then equalizes the concentrations on each side of the cell membrane. solvent: the liquid in which the solute is dissolved in. **solute**: what is dissolved into the solvent. **solution**: the liquid mixture in which the solute is dissolved into the. **semipermeable membrane**: this only lets in certain substances but not others. (also known as the plasma membrane)
 * Two Categories of Cell Transport: Passive and Active **
 * Different Types of Cell Transport **
 * Simple Diffusion: ** this term refers to a process where a substance passes through a membane without the aid of an integral protein membrane (an assembly of proteins attached to cell membrane). Simple diffusion is the movement of substances from an area of high concentration to an area of low concentration. This type of diffusion does not require energy, so therefor it is ** passive. **
 * What else is there besides diffusion? **
 * Related Terms: **

The plasma membrane is made up of lipids and pro teins that create a barrier of the cytoplasm of the cell and encloses the vacuole. Its main job is to regulate what enters and exits the cell. The plasma membrane consists of two phospholipid bilayers, proteins, and cholesterol. Every living cell has a plasma membrane as a part of its structure. In plant cells, the plasma membrane is the inner layer that provides protection and support to the cell. The cell membrane lines the plant cell wall and is the final filtration system for molecules being transported in and out of the cell. Molecules can enter and exit the cell through process like osmosis and diffusion. This also applies to prokaryotic cells. The plasma membrane is necessary for the life of a cell because without it, bacteria, viruses, and other harmful substances can enter it and shorten its life. A cell can be killed very easily, and if that were to happen without plasma membranes, than life would be unable to sustain itself on earth.
 * What is the Plasma membrane? **

Endocytosis and Exocytosis! **Endocytosis** is the consumption of matter by a living cell from its membrane to form a **vacuole**. During endocytosis, phagocytosis takes place by the cell me mbrane. **Phagocytosis** is refers to the ingestion of bacteria with phagocytes. Also, pinocytosis occurs, where the ingestion of liquid into a cell by the budding of small vesicles from a cell membrane happens. **Exocytosis** is the process of cell transport by which. the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane within the cell membrane. ** vacuoles ** : sac-like structures that store materials such as water, salts, proteins, and carbohydrates. **phagocytes**: type of cell in the body that ingests bacteria
 * What falls under **** "Active Transport"? **
 * Related Terms: **

http://www.youtube.com/watch?v=1ZFqOvxXg9M&feature=fvw
 * Animation showing Passive and Active Transport: **


 * __Helpful Terms for this chapter:__ **
 * cell membrane ** : thin flexible barrier that cell is surrounded by
 * cell wall ** : supporting later around the membrane
 * lipid bilayer ** : the composition of cell membranes is the lipid bilayer, and double layered sheet
 * concentration: ** mass of the solute in a given volume of solution, or mass/volume
 * diffusion: ** when particles move from an area where they are more concentrated to an area when they are less concentrated
 * equilibrium ** : when the concentration of the solute is the same throughout the system
 * osmosis: ** the diffusion of water through a selectively permeable membrane
 * isotonic: ** when the solutions are of the same strength
 * hypertonic: ** when the solution is “above strength”
 * hypotonic: ** when the solution is “below strength”
 * facilitated ** diffusion: molecules that cannot diffuse across the cell membranes lipid bilayer on their on move through the protein channels instead.
 * Active transport: ** requires energy. The active transport of ions across a cell membrane is general carried out by transport proteins.
 * Phagocytosis: ** extensions of cytoplasm surround a particle and package it within a food molecule
 * Endocytosis ** : process of taking material into the cell by the means of pockets of the cell membrane. The pocket breaks loose from the outer potion of te ell membrane and forms a vacuole within the cytoplasm.
 * Pinocytosis ** : where many cells take up liquid from the surrounding environment. Tiny pickets form along the cell membrane, fill with liquid, and punch off to form vacuoles from within the cell.
 * Exocytosis ** : the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell. The removal of water by means of a contactile vacuole is one example of this type of active transport.

** Here are a couple of websites that might help you further understand the concept of cell transport! **
** diffusion: ** http://edtech.clas.pdx.edu/osmosis_tutorial/diffusion1.html
 * cell membrane ** : http://www.ibiblio.org/virtualcell/textbook/chapter3/cms1.htm
 * active transport: ** http://bcs.whfreeman.com/thelifewire/content/chp05/0502002.html

-class notes -Prentice Hall Biology text book, chapter 7
 * General Information Sources **

Google Image Result for Http://www.biology.arizona.edu/Cell_Bio/problem_sets/membranes/graphics/Active_Transport.gif."// Google//. Web. 13 Jan. 2011. .__
 * Works Cited **

"Google Image Result for Http://www.daviddarling.info/images/active_transport.jpg."// Google//. Web. 13 Jan. 2011. .

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