Robert hooke saw the first cork cells in 1665. he also coined the word "cell" at the same time. during the next 150 years, scientists developed cell theory. they discovered cell organelles and described the cell as the basic unit of all life. one point of cell theory was not accepted until the early 1900's. that point was the cells give rise to other cells. for much of this time, many scientists still believed that cells just appeared. that idea was called spontaneous generation. people believed that living cells to develop from non-living things, like meat or soup. why did it take over 150 years for the scientific community to accept the last point of cell theory: cells give rise to other cells?

The answer to the question: Why did it take over 150 years for the scientific community to accept the last point of cell theory: cells give rise to other cells?, would be, that microscopic technology had not been advanced enough for scientists to be able to disprove Hooke´s observations, that gave support to the idea of spontaneous generation of cells, until Anton van Leeuwenhoek, through his own observations of sexual cells, and how they combined and divided, put forth the beginnings of what would later be termed as Cell Theory. Later on, it is scientists such as Schwann and Schleiden, as well as Rudolf Virchow, in 1839, that managed to finally establish this Cell Theory thanks to the advancement in microscopic technology.

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.