Sunday, September 16, 2012

Term 3


We learnt the structure of cells in this term. Although i have learnt it during primary 6 but this is more of a more detailed and "inside: of an animal cell and a plant cell. For example more detailed parts inside parts.
Like ribosomes, which is for the synthesis of proteins. 

Ribosomes

The ribosome is a large complex of RNA and protein which catalyzes protein translation, the formation of proteins from individual amino acids using messenger RNA as a template.This process is known as translation. Ribosomes are found in all living cells.





And also mitochondria, which is for the release of energy.
It helps in respiration, and it releases energy!

     


Mitochondria

In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle found in most eukaryotic cells.These organelles range from 0.5 to 1.0 micrometer (μm) in diameter. Mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signalingcellular differentiationcell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several human diseases, including mitochondrial disorders and cardiacdysfunction, and may play a role in the aging process. The word mitochondrion comes from the Greek μίτος mitos, thread, + χονδρίον chondrion, granule.
Several characteristics make mitochondria unique. The number of mitochondria in a cell varies widely by organism and tissue type. Many cells have only a single mitochondrion, whereas others can contain several thousand mitochondria. The organelle is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, the intermembrane space, the inner membrane, and the cristae and matrix. Mitochondrial proteins vary depending on the tissue and the species. In humans, 615 distinct types of proteins have been identified from cardiac mitochondria, whereas in Murinae (rats), 940 proteins encoded by distinct genes have been reported. The mitochondrial proteome is thought to be dynamically regulated. Although most of a cell's DNA is contained in the cell nucleus, the mitochondrion has its own independent genome. Further, its DNA shows substantial similarity to bacterial genomes.


       

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