Plasma membrane is the outer covering of cell protoplast in eukaryotes and prokaryotes, it forms a barrier between the internal component of cell and external environment. The plasma membrane allows the movement of substance inside the cell or between the cell.Complete Answer:
The plasma membrane is the important part of all the cells, in case it gets ruptured or breaks down the protoplasmic content gets dispersed in the surrounding medium by which the cell is unable to exchange material with surrounding, and soon it will die.
The plasma membrane is a lipid bilayer with integral protein arranged in a mosaic manner. It shows fluidity which is important to allow interaction of molecules within the membrane and also help in cell growth, secretion, cell division, and the formation of the intercellular junction. Plasma membrane shows the different types of modification which allow performing a special type of function in the cell. Additional information:
Microvilli is an outermost out fold of plasma membrane present on that cell which functions for absorption. The number of microvilli on the surface of a cell depends upon its function, normally it ranges between 1000 to 2000 microvilli per cell.
Pores are the infolding of the plasma membrane which allow the movement of substance between the cells and between cell and surrounding.
Intercellular junction forms a connection between adjacent cells, the intercellular junction is of various types like interdigitation which is finger-like folds to help fit adjacent cells together. It also provides a large surface area for the exchange of material.
Intercellular bridges allow rapid conduction of stimuli between adjacent cells.
Tight junctions present in animal cells which hold the adjacent cell together in a series of networks. It is present in those cells of epithelia where filtration occurs through the cell.
Gap junction is the cytoplasmic connection between adjacent cells through connections.
Desmosomes present in the adjacent cell where circular thickening present inside the cell, in these regions several tonofibrils are embedded which keep the cell firmly together.
Zonula adherens are desmosomes without tonofibrils occurring on the inner surface of the membrane containing microfilament.
Plasmodesmata are protoplasmic bridges that mostly occur in the plant cell. It is present in the areas where pits and pores are present which allow the movement of substances between cells.So, the correct answer is ‘(a) Protoplasmic content will be dispersed in the surrounding medium’.Note:
The plasma membrane also shows cell movement with the help of cilia and flagella. It also helps certain cells in performing movement by forming pseudopodia in Amoeba and undulations in fibroblasts.