Category Archives for "Cell Biology"

Plastid : Types, Structure and Functions

Plastids are the cytoplasmic organelles which are associated with the special metabolic process of the plant cells. It is the second largest organelle of the cell which is bounded by a double unit membrane and may be colored or colorless. Mayer and Schimper first used the term plastid. Plastids are found in plant cells and […]

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Endoplasmic Reticulum : Types, Structure and Functions

All living organisms are composed of cells and cell products. Each eukaryotic cell contains several cytoplasmic organelles. Among the organelles, endoplasmic reticulum performs as intracellular transport system for various substances and also helps to exchange the materials between nucleus and cytoplasm.  Prokaryotic cells and RBC (red blood cell) do not have any endoplasmic reticulum.Endoplasmic reticulum […]

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Golgi Body : Structure and Functions

Golgi body is a flattened, membrane-bounded, parallely arranged sacs and other vesicles usually located near the nucleus in the cytoplasmic matrix of almost all eukaryotic cells. It is also known as Golgy complex, Golgi apparatus, Golgiosome, Lipochondria and in the plant cell, it is also called Dictyosome. Camillo Golgi first observed it in the nerve […]

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Mitochondria : Definition, Structure and Functions

Definition: The word mitochondria come from two Greek words, mito meaning thread and chondrion meaning granule. It has double membrane enclosed rounded or rod-like or filamentous bodies which generate chemical energy in the form of ATP. It is scattered throughout the cytoplasm in most of the cells.
History of Mitochondria: Scientist Kolliker (1850) first observed mitochondria in the striated muscle. Flemming (1882) named it as fila. Rechard Altmann (1897) referred to the mitochondria as Bioplasts. Carl Benda (1897) first called these organelles as mitochondria.
Distribution and occurrence: It is not found in the prokaryotic cell and matured circulated RBC. Generally they are evenly distributed in the cytoplasm. It is also found in the base of the proximal convoluted tubules of nephron. The number of mitochondria present in the cell depends on its activities. Plant cell contains less number of mitochondria than animal cell. A normal liver cell may contain 1000-1600 mitochondria while some oocytes may contain more than 300000 mitochondria. On the other hand, Microasterias algae contain only one mitochondrion
Structure of Mitochondria: Mitochondria have generally spherical or rod-shaped or filamentous structures. It is about 3.0-7.0 µm in length and 0.2-2.0 µm in diameter. It usually consists of two unit membranes, two chambers, mitochondrial matrixs and mitochondrial particles. Every mitochondria is bounded by the double membranes, the outer membrane and inner membrane. Each membrane is made up of lipo-protein and it is about 60 Angstrom thick. The outer membrane is smoothed and covers the mitochondria but the inner membrane remains folded inward at various points to form a number of incomplete partitions which are known as the cristae or mitochondrialis cristae. The two membranes remain 60-80 Angstroms apart from each other. The space between the two membranes is filled up with fluid.

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Cell Structure and Function

The cell is the structural and functional unit of life, which is also known as “building blocks of life.” The science which deals with the study of cells is called Cytology or cell biology. Robert Hooke first discovered the cells in 1665. Matthias Jakob Schleiden and Theodor Schwann first developed a cell theory in 1839. […]

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