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 th...
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Development of Male Gametophyte-digieduco

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Microgametogenesis i.e. the development of Male Gametophyte :Microspore i.e. pollen grain is the first cell of the male gametophyte germination starts within the microsporangium.
The nucleus divides to form a larger vegetative cell or tube cell and a smaller generative cell at one corner with the spore wall-later the generative cell loses contact with the spore wall and appears as a spindle-shaped, elliptical or lenticular cell.
Development of Male Gametophyte-digieduco

The next stage is the division of generative cell which may take place either in pollen grain or in the pollen tube that comes out through a germ pore after pollination. At the time of pollination, the pollen grain i.e. microspore may be either in two-celled or three-celled stage. In all cases however the generative cell divides into two male cells i.e. male gametes. The vegetative cell (sometimes called tube nucleus) lies either behind the male cells or near the tip of the pollen tube. Anyway, the vegetative cell has no important function, rather a degenerating structure.

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