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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Plastids-digieduco

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These are also protoplasmic bodies. denser than cytoplasm, variously shaped and are separated from the cytoplasm by definite membrane system. Plastids develop from similar primordial organelles. One type of plastids may change into other. On the basis of the presence or absence of pigments, plastids are classified into two major types such as non-pigmented and pigmented. Non-pigmented i.e. colourless plastids are called eucoplasts, found mainly in the cells of underground organs and in the meristematic cells. Leucoplasts include amyloplasts (which synthesize starch), elaioplasts (which synthesize fats and oils) and proteinoplasts (which synthesize protein).

Pigmented plastids consist of-

(a) Chloroplasts or green plastids-bear green pigment chlorophyll, found in the cells of green plant parts e.g., stem, leaves etc.

(b) Chromoplasts or coloured plastids other than green i.e. yellow, orange, red etc. and contain the pigment carotene, found in the cells of flowers, fruits etc. 

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