A cell is the basic structural and functional unit of living organisms. Cells vary widely in size, from 5 micrometers in sperm cells to 1 meter in nerve cells, and 120 micrometers in ovum cells. The shape of cells depends on their function, with human red blood cells being circular and biconcave to easily pass through capillaries, nerve cells being branched to conduct impulses, and white blood cells able to change shape to engulf microorganisms. The detailed internal structure of cells can only be seen with electron microscopes, which allow magnification of up to 500,000 times compared to 2000 times with compound microscopes.
2. What is cell?
- Cell is the basic Structural and
functional.
unit of living organisms.
- The smallest unit that can live on its
own.
3. Size Of Cell In Humans
Smallest cell
Sperm cell
Size: 5 µm
Longest cell
Nerve cell
Size: 1 m
Largest cell
Ovum cell
Size: 120 µm
4. Shape Of Cell
Cells vary in shape.
Variation depends mainly upon
the function of cells.
Some cells like Euglena and
Amoeba can change their shape,
but most cells have a fixed shape.
8. Structure Of Cell
The detailed structure of a cell has
been studied under compound
microscope and electron microscope.
Certain structures can be seen only
under an electron microscope.
The structure of a cell as seen under
an electron microscope is called
ultrastructure.
