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Showing posts with the label Notes Botany Hons

Pleomorphism of Lysosomes

  Pleomorphism of Lysosomes Lysosomes show pleomorphism, which means they occur in many different forms according to their functional state. They are not always identical in shape, size, or contents. Their appearance changes depending on whether they are newly formed, involved in digestion, or storing undigested waste materials.  Lysosomes are membrane-bound organelles containing hydrolytic enzymes. These enzymes digest proteins, lipids, carbohydrates, nucleic acids, and other cellular materials. Since lysosomes perform different digestive functions inside the cell, they appear in different structural forms. This property is called pleomorphism.  The main pleomorphic forms of lysosomes are primary lysosomes, secondary lysosomes, autophagic vacuoles, and residual bodies. Primary lysosomes are newly formed lysosomes produced by the Golgi apparatus. They contain inactive hydrolytic enzymes and have not yet taken part in digestion. They are small, spherical vesicles surround...

Fungi: Characteristics

GENERAL CHARACTERISTICS OF FUNGI 1)They are cosmopolitan in distribution and can occur in any habitat where life  is possible. Some fungi occur in fresh or marine water, others are terrestrial  and still others are air borne. Many species are parasitic, infecting plants,  animals and human-beings. 2)The plant body of fungi typically consists of branched and filamentous hyphae,which form a net-like structure, known as mycelium. 3)The hyphae are aseptate and coenocytic (as in Phycomycetes) or septate and uni-. bi-or multinucleate (as in Ascomycetes, Basidiomycetes and  Deuteromycetes). 4) The septa usually have simple pores but in Basidiomycetes septa with dolipore occur. On both the sides of the dolipore, a double membranous structure -septal pore cap or parenthosome occurs. These septal pores form a valve like structure. 5) With the exception of slime molds, the protoplast remains surrounded by a distinct cell well. The main component of the cell wall is the fungal c...