cell: the structural and functional unit of life
Cell is a unit of structure and function. All living things are made up of cells These are also units of function, reproduction, growth, respiration, excretion etc. Cell is small mass of protoplasm. It contains nucleus. cytoplasm and cell membrane Cell Discovery Cell was discovered by Robert Hook in 1665 A D A French biologist, New Jordon, did good research in this field According to him all cells have living contents and he named it sarcade, in 1835. Then, two German botanists, Mathias Schleiden and Theodor Schwau, in 1938 and 1939, gave the theory that cell was the basic structural unit of all living things Another scientist Rudolf Virchow said Omina cellulla is kind of cellula which means all cells are from the cells Pinocytuvesivle, Mitocondria, Chromosomes, Nuclear membrane, Nucleous, Nuleoplasm, Golgi bodies, Reticulum Endoplasm, Ribosomes, Centrioles, Lysosomes and Cell membrane. There are unicellular plants and animals, for example plant euglena and animal amoeba There are multicellulaer organisms and plants as well The man, snake, bird, housefly, etc, consist of millions and billions of cells Similarly rice, wheat, cotton, rose etc, all consist of million and billions of cells Animal Cell Animal cell bears an oval shape. The nucleus is surrounded by cytoplasm. Cell is surrounded by a thin layer called Cell membrane. It the work of cell membrane to control the movement of substances in and out of the Cell Nucleus controls all the activities of the cell Every cell is filled with a living material which is said to be cytoplasm Nucleus is a large spherical structure With the help of nuclear membrane, different substances diffuse in and out of the nucleus The nucleoplasm is thick and transparent, present in the nucleus. It contains a network of line thread called the chromosomes. In the cell, chromosomes usually occur in pains. There are 46 chromosomes in man, 68 in horse, 24 in and 32 in earthworm Nucleus is also present in the nucleolus, its function is synthesis of ribosome Ribosome is small spherical organ suspended throughout the cytoplasm Five to ten ribosomes make clusters Ln the cytoplasm, there are large structures called mitochondria. Each mitochondrion is covered by a double membrane and they are placed where is produced and respiratory process carried Golgi bodies make plasma membra required for daughter cells during the cell division Lysosoem contain digestive or hydrolytic enzymes. It has various morphological shapes intermally their structure is same There are three different types of cells Somatic Cells (2) Stem Cells (3) Germ Cells.