Plant cells are classified into three types, based on the structure and function, viz. parenchyma, collenchyma and sclerenchyma. The parenchyma cells are living, thin-walled and undergo repeated cell division for growth of the plant. They are mostly present in the leaf epidermis, stem pith, root and fruit pulp. Mature collenchyma cells are living, and provide stretchable support to the plant. Lastly, sclerenchyma cells (e.g. fiber cells) are hard, non-living and give mechanical support to plants. Now, let us see the different parts of a plant cell with their significant roles.
1. Cell Wall
Cell wall is the outermost tough and rigid layer, which comprises cellulose, hemicellulose, pectin and at other times, lignin. As expected, it remains connected with the cell walls of other cells. The prime functions of cell wall are protection, giving structural support and helping in the filter mechanism.
2. Cell Membrane
Cell membrane, also called plasma membrane, is present inside the cell wall and surrounds the cytoplasm. It connects the intracellular components (organelles and cytoplasm) with the extracellular environment, and helps in protection and transportation. The cell membrane is permeable to specific substances only.
3. Plasmodesmata
Plasmodesma (plural plasmodesmata) is a small opening, which connects plant cells with each other. Present only in some types of algal cells and plants cells, this connecting channel enables transport of materials and allows communication between the cells. In a single plant cell, about 1,000-100,000 plasmodesmata are present.
4. Nuclear Membrane
The nuclear membrane and the nuclear envelope mean one and same thing. As the name reveals, it is the outer covering of the nucleus. It separates the cytoplasmic contents from the nuclear contents. Nonetheless, minute pores (nuclear pores) are present for exchanging materials between the nucleus and cytoplasm.
5. Nucleus
Nucleus is a