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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Structure of Microspore (Pollen grains)-digieduco

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Structure of Microspore (Pollen grains):
Microspores or pollen grains are asexual reproductive units produced within anther lobes i.e. microsporangia.
Structure of Microspore (Pollen grains)-digieduco

They are of various forms-granular, ellipsoidal, circular, triangular, etc. The pollen grains have outer coat, called exine and inner coat, called intine : the exine is a tough. cutinised wall-layer resistive to mechanical injury, may be smooth but usually beset with spiny, warty. tubercular outgrowths-there may be other various markings on the exine. The intine is very thin, delicate, elastic and cellulosic wall layer. The dimension of pollen grains may be small or they are sometimes big enough to be seen with the naked eye. The pollen grains have small pores in the exine through which the pollen tube comes out during germination, these pores are known as germ pores or slits. A pollen grain before germination contains a single nucleus surrounded by cytoplasm.

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