Cell membrane function and difference-digieduco

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  Functions of cell membrane : (a) The proteins and enzymes present in the cell membrane helps in the transport of certain substances like sugar, sodium and other ions etc. across the cell membrane. (b) Cell membrane protects the internal structures of the cell and different organelles of the cytoplasm. (c) It maintains the shape of the cell. (d) It acts as a selective permeable membrane because it allows to pass certain substances while others are not, hence it helps in the transport of selective materials from and to the cells. (e) The membranes on the cytoplasmic organelles and nucleus most probably formed from the plasma membrane. (f) Other important functions of cell membrane of the cells are endocytosis and exocytosis . Endocytosis is the process by which materials are transported into the cells by the formation of vesicles. It includes two processes-phagocytosis (cell eating) and pinocytosis (cell drinking). The reverse process of endocytosis is exocytosis. During this p
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Multiple or composite fruits-digieduco

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Multiple or composite fruits are the products of whole inflorescence together with its component parts.


There are two types as follows :
Multiple or composite fruits-digieduco

(i) Sorosis-Examples are the fruits of Ananas comosus (Pine apple, Bromeliaceae). Artocarpus heterophyllus (Jack fruit, Moraceae), Moms indica (Moraceae) etc.

In Ananas comosus there is a crown of sterile leafy bracts at the apex of the fruit ; the surface of the fruit is represented by polygonal areas, each of which is the united ovary of the component flower of the inflorescence spike. The rachis, perianth and bracts become fleshy and succulent forming the edible parts of ,the fruit. In Artocarpus heterophyllus the rachis is club shaped; not fleshy ; the edible Juicy ovaries of fertile flowers and bracts become succulent -at the axils of bracts there are fleshy perianth (calyx) which also forms the edible part.

In mulberry (Morus indica), dry achenes are enclosed by fleshy perianths
Multiple or composite fruits-digieduco

(ii) Syconus-It deveIops from the hypanthodium infiorescence. The fleshy rachis of the inflorescence becomes succulent enclosing the minute achenes, each of which is developed from female flowers of the hypanthodium-so it is a multiple or composite fruit.

In Ficus benghalensis and other Ficus sp, the hollow pear-shaped receptacle becomes fleshy which encloses a number of fruits or achenes developin g from female flowers closed within the receptacle. In Dorstenia the coenanthium develops achenes on the open receptacle forming Syconus type of multiple fruit. 

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