AP BIOLOGY

Detailed explanation-1: -Cell theory also states that cells are the basic functional unit of living organisms and that all cells come from other cells. Although this knowledge is foundational today, scientists did not always know about cells. The discovery of the cell would not have been possible if not for advancements to the microscope.

Detailed explanation-2: -The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells).

Detailed explanation-3: -Rudolf Virchow, a German pathologist (1821–1902), famously wrote “omnis cellula e cellula”-all cells come from other cells-meaning that spontaneous generation of living things from inanimate matter does not occur over periods as short as our lifetimes.

Detailed explanation-4: -New cells are created from existing cells through a process referred to as the cell cycle. One cell can make a copy of itself and form two new daughter cells. There are two major tasks that have to happen every cell cycle. First, cells have to make an exact copy of their DNA.

Detailed explanation-5: -The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells. Rudolf Virchow later made important contributions to this theory.