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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What is floral formula and floral diagram- digieduco

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Floral Formula : Floral formula is an expression summarising the information regarding the number of floral whorls and their respective floral members in different whorls, also their cohesion and adhesion through some symbols like K, C or P, A and G; K stands for calyx, C for corolla, P for perianth (when calyx and corolla are not distinguishable), A for androecium and G for gynoecium.
In a formula ‘( )’ indicates cohesion of members, indicates adhesion of members. The line above or below the gynoecium i.e. ‘G’ (or the number) is very significant e.g. G indicates inferior position of the ovary, Q indicates superior position of the ovary. a is the symbol of indefinite number of parts, e.g. A alpha i.e: stamens are many and free in an androecium whorl. If members of the same whorl are arranged in two or more series or whorls, then ‘+’ sign is put between them e.g. K2+2 i.e. the sepals in a calyx (K) whorl are 4 but arranged in two series or whorls(2 in outer and 2 in inner whorl). The symbol for actinomorphic (regular) flower is (+) while zygomorphic (irregular) is %.


Floral Diagram:
Floral diagram is a diagram illustrating the relative position and number of floral members in each whorl in relation to the inflorescence or mother axis. In a floral diagram everything regarding floral morphology except the thalamus , perigyny, hypogyny and epigyny can be represented.
What is floral formula and floral diagram- digieduco

In order to construct the floral diagram of a flower, the flower-bud should be Cut transversely and then examined carefully from the above with the help of a good hand lens. It will be observed that the floral leaves are arranged in successive circles or spirals. The aestivation of sepals and petals will be recognised easily. the stamens are represented by two-lobed or four-lobed small structures. The innermost circle represents the number and position of carpels. Upper black dot or a round represents the position of mother axis i.e. inflorescence axis.

In a floral diagram, the calyx whorl remains as outermost, then comes corolla whorl, next to that lies androecium and in the centre, the gynoecium lies. The portion of a flower lying towards the axis is called posterior region while portion away from and opposite to axis is called anterior region. Adhesion and cohesion of floral members may be represented by joining the parts simply or by connecting them with lines.

In a regular i.e. actinomorphic flower, the vertical line passing through the mother axis and the centre of the diagram is known as median plane-this line divides the flower into two equal halves i.e. right and left. The vertical line passing through the centre and connecting the median plane at right angle is known as lateral plane-this line divides the flower equally into posterior and anterior halves. Again, the two vertical lines that bisect the angles formed by the median and lateral planes are known as diagonal planes-each of these divides the flower diagonally into two equal halves.

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