AP BIOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. The first part states that all organisms are made of cells. The second part states that cells are the basic units of life.

Detailed explanation-3: -This means that cells form the parts or an organism and carry out all of the an organism’s processes, or functions.

Detailed explanation-4: -Virchow’s theory stated that just as animals are unable to arise without previously existing animals, cells are unable to arise without previously existing cells. The idea that new cells arose from pre-existing cells in both diseased and healthy tissue was not original.

Detailed explanation-5: -Credit for developing cell theory is usually given to two scientists: Theodor Schwann and Matthias Jakob Schleiden. While Rudolf Virchow contributed to the theory, he is not as credited for his attributions toward it.