Life

The living cell

In 1665, while observing a sliver of cork, Robert Hook discovered the cell, that extremely complex building block in multicellular beings. In fact, each one contains an incredible number of structures which can be observed through an electron microscope and each one of them performs specific biological and biochemical activities that make the cell into a perfectly organized living “factory”.One can see the cell’s evolution by watching unicellular organisms through the microscope. Within these cells one can see complex structures and organs which are similar to other multicellular organisms. As early as in 1940, following the invention of the electronic microscope, we knew of the existence of a much simpler form of life: the virus. In spite of its tiny size (only a few hundred millionths of a millimeter) and its simplicity compared to other unicellular organisms, it still has a nucleic acid. This nucleic acid known as DNA (deoxyribonucleic acid) is the basic building block of life and is responsible for the transmission of a being’s hereditary features. Many viruses contain this nucleic acid that is the same DNA that transmits hereditary features in extremely complex beings such as man. Viruses obviously do not represent life as it was created on Earth because they are parasites that need other plant or animal cells to live on. Nevertheless they show a connecting bridge between chemical and living substances. In 1967 two American scientists, Arthur Kronberg and Mehran Goulian, were able to synthesize, that is to produce artificially in a lab the DNA and joined it with protein molecules taken from a virus. As a result they created a new virus that could reproduce itself. Thus they had reached the moment when life begins.