Question

Who proposed a modification in the cell theory?
A. Schleiden and Schwann
B. Rudolf Virchow
C. Robert Hooke
D. Marcello Malpighi

Answer 1

Hint: Cell theory formed the basis of the structural organisation of an organisation how organisms are formed. It is a historic and universally accepted theory.

Complete answer: Initially, two scientists named Theodor Schwann and Matthias Jakob Schleiden formulated the cell theory for the first time in the year 1839. Schleiden suggested that a large number of plants are composed of different types of cells and these cells form tissues. Later Schwann suggested different types of animal cells and these cells have a thin outer layer which is known as plasma membrane today. The basic conclusions of their theory are All living organisms plants and animals based on their studies composed of cells and products of cells.
However, the cell theory was first given by Schleiden and Schwann failed to suggest how cells are formed. Therefore, later in the year 1855, a scientist named Rudolf Virchow modified this cell theory and stated that new cells are formed from the pre-existing cells i.e. Omnis cellula-e cellula. Thereby, he modified the cell theory and gave final shape to the cell theory. This was the final modification of the cell theory.
i. Robert Hooke in the year 1665 discovered the cell. With the advancement of the microscope, he saw small compartments in the dead cell walls of the plant cells cork. He published his work in his publication Micrographia. The later cell is recognised as the structural and fundamental unit of life.
ii. Marcello Malpighi was the first person to discover capillaries in animals. He was the one who discovered a link between arteries and veins. He discovered all these in a fishtail. His discovery was an important contribution to the field of physiology.

Additional information: Postulates of cell theory are;
i. All living organisms are composed of the cell.
ii. A new cell arises from preexisting cells.
iii. The cell is the structural and functional unit of life.
So, the correct answer is option B.

Note: Cell theory was important for understanding cells because they form the basis of life. Cell theory helped in knowing the structure of different cells and how they formed the basis of life and cell theory helped in knowing single-celled and multicellular organisms.