Lysosomes

Description: A membrane-bounded sac of hydrolytic enzymes found in the cytoplasm of eukaryotic cells.
lysosome.jpg

Function: Digests macromolecules by hydrolysis including proteins, polysaccharides, fats, and nucleic acids.
For an animated look at lysosomal function.
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter3/animation__lysosomes.html
A Look Inside A Lysosome
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.
electrogenic.jpg
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.

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.
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__phagocytosis.html

Lysosomal enzymes are also used to recycle a cell's own organic material in a process called autophagy.
autophagy.sa.may08.jpg
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.
peroxisomesfigure1.jpg


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.
http://www.univie.ac.at/ibmz/groups/hartigIm/peroxi.html
Note: Only look at biogenisis 1 and 2.

Function: Transfers hydrogen from various substrates to oxygen, producing hydrogen peroxide as a by-product.
What It Does For Plant Seeds.
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.
seed_growth.jpg
What It Does In The Liver.
Peroxisomes in the liver detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen, forming water.


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Mitochondriamitochondria2.jpg

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

protons.gif

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.

ATPanim.gif

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 dioxidechloroplasts.jpg
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.










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