2009-Mitochondria,+Chloroplast,+Lysosome,+and+Perioxisome

**__Lysosomes__**
__Description:__ A membrane-bounded sac of hydrolytic enzymes found in the cytoplasm of eukaryotic cells.

__Function:__ Digests macromolecules by hydrolysis including proteins, polysaccharides, fats, and nucleic acids. [] __Membrane__ The lysosome is a membrane sac that allows the regulation of pH for the enzymes it contains. The intereior of the lysosome is kept at an optimal pH of 5, perfect for lysosomal enzymes. How does the lysosome mantian this optimum pH you might ask? Well the answer to that question is found by taking a closer look at the membrane of this organelle. As you can see illustrated above the lysosome uses a series of proton pumps in it's membrane to maintain the optimal pH balance. By pumping hydrogen cations the proton pump is lowering the pH of the lysosome interior therefore causing the enzymes to be more active.
 * For an animated look at lysosomal function.**
 * A Look Inside A Lysosome**

__Lysosomal Enzymes__ The enzymes that are found in lysosomes are mainly used in the process of phagocytosis, breaking down substances brought in from outside the cell. []

Lysosomal enzymes are also used to recycle a cell's own organic material in a process called autophagy. __Cell Destruction__ At the end of a cell's life the lysosomes serve an important function in destroying the dead cell. Certian chemical signals are sent to the lysosomes telling them to release all of their digestive enzymes, and therefore causing the cell to digest itself.

__Peroxisomes__
__Description:__ A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide.

Peroxisomes differ from lysosomes in that they do not bud from the endomembrane system, instead they bud from incorporating proteins and lipids made in the cytosol. When peroxisomes reach a certian size they split in two. [] Note: Only look at biogenisis 1 and 2.

__Function:__ Transfers hydrogen from various substrates to oxygen, producing hydrogen peroxide as a by-product. Specialized peroxisomes called glyoxysomes are found in the fat-storing tissues of plant seeds. The enzymes in these peroxisomes start the conversion of fatty acids to sugar which the young plant can use for energy until it can produce it's own. Peroxisomes in the liver detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen, forming water.
 * What It Does For Plant Seeds.**
 * What It Does In The Liver.**



__Mitochondria[[image:mitochondria2.jpg align="right"]]__
__Description:__ The Mitochondria is an organelle in eukaryotic cells that serves as the site of cellular respiration. Mitochondria is the powerhouse of a cell __Function:__ breaks down carbohydrates, fats, and protein to make ATP. ATP powers all of the cells activity. The Mitochondrion synthesize ATP in a 2 step process.

__Step 1:__ The inter-membrane fills with protons, this is called the proton gradient. this is filled by NADH feeding electrons into electron feeding system

[[image:protons.gif width="354" height="208"]]
__Step 2:__ After the proton gradient is full, the ATP synthase enzyme complex lets the protons through the membrane to bond the ADP with another phosphate to make ATP.

[[image:ATPanim.gif width="347" height="213"]]
__What is the Proton Gradient?__ The Proton Gradient is when the protons that result from the production of NADH stay in the intermembrane of the mitochondria. Once the gradient is full, the ATP synthase enzyme complex bringsd the protons through the membrane and the protons link ADP and another phosphate group to create ATP. ATP is used to power all of the cells functions.

__Chloroplasts__
__Description:__ Chloroplast is an organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide __Function:__ Chloroplasts create ATP through photosynthesis, the process of using light to synthesize organic molecules from carbon dioxide and water. Chloroplasts have chlorophyll, chlorophyll traps light energy to use for photosynthesis, chlorophyll also. The products of Photosynthesis are glucose and oxygen.

For a simple animation of photosynthesis, click here

Chloroplast are part of the group called plastids, plastids are a family of organelles that all hold specific information. Chromoplasts hold the yellow and orange pigments that give color to fruit and flowers. Leucoplasts store oil, starch, and protein. and Chloroplasts preform Photosynthesis and give plants their green pigment.



"Animation of ATP synthesis in Mitochondria." //Homepages Web Server - UITS - University of Connecticut//. Web. 29 Oct. 2009. .

"Cell Organelles: Mitochondria." //Home of CELLS alive!// Web. 29 Oct. 2009. .

"Functions of mitochondria | epilepsy.com." //Epilepsy and seizure information for patients and health professionals | epilepsy.com//. Web. 29 Oct. 2009. .

//The kitchen garden//. Web. 29 Oct. 2009. . //Molecular Expressions: Images from the Microscope//. Web. 29 Oct. 2009. .

"Peroxisome." Web. 29 Oct. 2009. .

"A Proton Gradient Powers the Synthesis of ATP." //NCBI HomePage//. Web. 29 Oct. 2009. .