cells. It is optically inactive (isotropic). Plasmodesmata and Pits Plasmodesmata act as a channel between the protoplasm of adjacent cells through which many substances pass through. Moreover, at few regions, the secondary wall layer is laid unevenly whereas the primary wall and middle lamellae are laid continuously such regions are called pits .
The Pits of adjacent cells are opposite to each other. Each pit has a pit chamber and a pit membrane. The pit membrane has many minute pores and thus they are permeable. The pits are of two types namely simple and bordered pit.
Middle lamella Primary wall S S Cell Lumen S Portion enlarged with adjacent cells Secondary wall Middle lamella Primary wall S Cell Lumen S S Secondary wall T.S. of a Plant cell (details of cell wall) Figure . : Plant cell wall Function of Cell Membrane The functions of the cell membrane is enormous which includes cell signalling, transporting nutrients and water, preventing unwanted substances entering into the cell, and so on. Cytoplasm Cytoplasm is the main arena of various activities of a cell.
It is the semifluid gelatinous substance that fills the cell. It is made up of eighty percent water and is usually clear and colourless. The cytoplasm is sometimes described as non nuclear content of protoplasm. The cytoplasm serves as a molecular soup where all the cellular organelles are suspended and bound together by a lipid bilayer plasma membrane.
It constitutes dissolved nutrients, numerous salts and acids to dissolve waste products. It is a very good conductor of electricity. It gives support and protection to the cell organelles. It helps movement of the cellular materials around the cell through a process called cytoplasmic streaming .
Further, most cellular activities such as many metabolic pathways including glycolysis and cell division occur in cytoplasm. . Cell Organelles . .
Endomembrane System System of membranes in a eukaryotic cell, comprises the plasma membrane, nuclear membrane, endoplasmic reticulum, golgi apparatus, lysosomes and vacuolar membranes (tonoplast). Endomembranes are made up of phospholipids with embedded proteins that