Eukaryotic Cells

The cell is the basic unit of life. It is the smallest unit of living matter. Many cells together form the tissue, and many tissues together form the organs of the body. Generally, there are three types of cells; the eukaryotic cells which contain the nucleus i.e. plants and animal cells, the prokaryotic cells which lack the membrane bound nucleus i.e. bacteria and the archeans that possess qualities of both prokaryotes and eukaryotes. Prokaryotic cell size ranges between 1.1-1.5 µm wide and 2.0-6.0 µm wide. They can either be rod-shaped (Bacillus) or spherical shaped (Coccus).

A bacterial cell envelop consists of the cell wall, plasma membrane and the glycocalyx. The glycocalyx is a layer of polysaccharides that lies outside the cell wall in some bacteria. It aids against

There are two kids of ER; the rough ER which is studded with ribosomes that synthesize proteins and smooth ER that lacks ribosomes for lipid synthesis. The ribosomes are also found in all cells and are small bodies free or attached to ER. They are used for protein synthesis. The mitochondria are an organelle that carries out cellular respiration producing ATP molecules. The lysosome breaks down larger food molecules into small molecules, and also contains enzymes used to digest old cell parts. The peroxisome is a vesicle that is involved in fatty acid metabolism. The Golgi apparatus consists of stacks of flattened sacs that have a cis and trans face. They process, package and secrete modified proteins. The centrosome is a microtubule organizing center that lacks the centrioles. The centrioles are paired structures near the nucleus and are made of a cylinder of microtubule layers. They separate the chromosome pairs during mitosis. The microtubules are protein cylinders that aid movement of organelles. The actin filaments are protein fibers that play a role in cell division and