shapes of various cells in human body and plasma membrane
Answers
Answer:Cell- Number, Shape and Size
There are millions of living organisms around us. Each of them has different size and shape. Moreover, their organs also vary in size, shape and number of cells.
cell size
Cell Number
Our human body has trillions of cells. Surprisingly enough, each of these cells varies in shapes and sizes. There are several different groups of cells which perform a plethora of functions. Every organism that has more than one cell is known as the multi-cellular organism.
Even an organism that has billions of cells happens to begin its life with a single cell, that is a fertilized egg. This fertilized egg goes on to multiply, thereby increasing the number of cells as the development takes place. If an organism is a single-celled organism, then it would be a unicellular organism.
A single-celled organism is just as capable of performing all the requisite life functions. So, just like the multicellular organisms, the single-celled organisms also perform their functions but only using a single cell. Every single-celled organism such as an amoeba captures and digests food, respires, excretes, grows and reproduces.
The similar functions are performed in the multicellular organisms. However, in their case, these functions are performed by a group of specialised cells forming different tissues. These tissues, in turn, go on to form organs.
Learn more about Parts, Structure and Functions of Cell in more detail here.
Cell Shape
Usually, the cells are round, elongated or spherical. There are also some cells which are long and pointed on both the ends. Such cells exhibit spindle shape. In some cases, the cells are very long. Some may be branched like the neuron or the nerve cell. The nerve cell transfers and receives messages.
It, therefore, helps in coordinating and controlling the working of the different parts of the body. The components of the cell are enclosed in a membrane. This membrane provides shape to the cells of animals and plants. There is a cell wall surrounding them. The cell wall is an additional covering over the cell membrane in the plant cells. It offers rigidity and shape to the cells.
Cell Size
The cell size is variable. In the living organisms, the cell size may be as small as a millionth of a metre or may be as large as a few centimetres. Usually, all the cells are microscopic in size and aren’t visible to the naked eye. Thus, they need to be enlarged by a microscope for seeing.