All the living organisms like plants, animals, humans are made up of cells. These cells grow and divide, function, repair and self destruct in a controlled manner so that the organism develops properly. A human body consists of 200 different kinds of specialized cells making up to around 1014 cells in total. Lot of important functions are carried out by specialized cells like nerve cells, blood cells, heart cells, epithelial, exocrine and endocrine cells.
The normal cells have certain important characteristics like cell reproduction, cell adhesion, cell destruction and cell specialization that are necessary for the proper functioning of tissues, organs and body systems. These cells reproduce correctly, stop reproduction and also self-destruct if necessary.
Cell reproduction is done in order to replace the damaged or aged cells with new ones. Cells divide and reproduce in two ways – Mitosis and Meiosis. Mitosis is a process of asexual reproduction that takes care of general growth and repair of the body. This process regenerates all cells except the sex cells by splitting into two identical copies of the original cell. Sex cells reproduce through Meiosis in which cells split to form new cells.
Cells have adhesion molecules on their surface that help them to adhere to the cell membranes of other cells. Cell adhesion helps cells to stay in their location. Normal cells have the ability to develop into specialized cells like heart cells, brain cells, lung cells etc. When cells get damaged or injured, they destruct themselves through a process called apoptosis and white blood cells dispose them.