The endoplasmic reticulum (ER) is a large network of membrane-bound tubes and sheets. It looks like long tubules or round or oblong bags (vesicles). The ER membrane is similar in structure to the plasma membrane.There are two types of ER– rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). RER looks rough under amicroscope because …
Region between nucleus and cell membrane . A large region of each cell enclosed by the cell membrane. This region takes up very little stain. It is called the cytoplasm.The cytoplasm is the fluid content inside the plasma membrane. It also contains many specialised cell organelles. Each of these organelles performs a specific function for …
The nucleus has a double layered covering called nuclear membrane. The nuclear membrane has pores which allow the transfer of material from inside the nucleus to its outside, that is, to the cytoplasm.The nucleus contains chromosomes, which are visible as rod-shaped structures only when the cell is about to divide.Chromosomes contain information forinheritance of characters …
Plant cells, in addition to the plasma membrane, have another rigid outer covering called the cell wall. The cell wall lies outside the plasma membrane. The plant cell wall is mainly composed of cellulose. Cellulose is a complex substance and provides structural strength to plants.When a living plant cell loses water through osmosis there is …
SIZE OF THE CELLS : There is much variation in size, shape and number of cells in different organisms, and also in various parts of the body. Most of the cells are only a few micrometres in diameter and are visible only with the help of a microscope. SHAPE OF CELLS : Cells may be …
The cell has special components called organelles. How is a cell organised?If we study a cell under a microscope, we would come across three features in almost. every cell; plasma membrane, nucleus and cytoplasm. All activities inside the cell and interactions of the cell with its environment are possible due to these features..
Cells were first discovered by Robert Hooke in 1665. He observed the cells in a cork slice with the help of a primitive microscope.Leeuwenhoek (1674), with the improved microscope, discovered the free living cells in pond water for the first time. It was Robert Brown in 1831 who discovered the nucleus in the cell. Purkinje …
