Friday, 21 August 2015

Eucaryotic cell

A cell is an organised mass of protoplasm surrounded by a protective and selectively permeable membrane. protoplasm of cell is called protoplast. It is made up of cytoplasm, nucleus and vacuoles. Electron microscope has shown that cytoplasm has a complex organisation formed of cytoplasmic matrix and cell organelles. Genetic material or DNA is organised into chromosomes and chromotin.
                                      In the cytoplasm matrix large number of cell organelles like endoplasmic reticulum, plastids, mitochondria, Golgi bodies, centrioles, lysosomes, sphaerosomes, peroxisomes, vacuoles etc. are present. doubling membrane coverings occurs around plastids and mitochondria. Single membrane covering is found over endoplasmoc reticulum, Golgi bodies, lysosomes, sphaerosomes, peroxisomes and vacuoles. Organelles without a membrane covering are ribosomes.

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