Question

Compare the modern Cell Theory to the original Cell Theory

Answer 1

The original cell theory, established by Schleiden, Schwann, and Virchow, posited that all organisms are made of cells, cells are the basic unit of life, and all cells originate from existing cells. Modern cell theory builds on this by integrating knowledge about cell biochemistry, genetic information, and recognition of complex internal structures made possible through tools like the electron microscope.

Step-by-step explanation:

The original cell theory, formulated by Matthias Schleiden and Theodor Schwann, and later supplemented by Rudolf Virchow, states that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells. Modern cell theory, influenced by advancements and discoveries such as the invention of the electron microscope in the 1950s, has extended these principles to incorporate a deeper understanding of cellular biochemistry and genetic information within cells. While the core components remain the same, modern cell theory acknowledges the complexity of cells including the presence of organelles and the flow of genetic information.

The modern cell theory encompasses the following tenets:

1. All known living things are made up of cells.
2. The cell is the structural and functional unit of all living organisms.
3. All cells arise from pre-existing cells by division.
4. Energy flow (metabolism and biochemistry) occurs within cells.
5. Cells contain DNA which is found specifically in the chromosome and RNA is present in the cell cytoplasm.
6. All cells are basically the same in chemical composition and metabolic activities.
7. All basic chemical and physiological functions are carried out inside the cells (movement, digestion, reaction to stimuli etc.).
8. Cell activity depends on the activities of sub-cellular structures within the cell (organelles, nucleus, plasma membrane, etc.).

The original cell theory, which dates back to the mid-19th century, was based on the work by scientists like Robert Hooke, who coined the term 'cell', and the collective work of Schleiden, Schwann, and Virchow, which introduced the concept of cells as the fundamental unit of life and the idea that all cells come from pre-existing cells.

The discoveries leading to a better understanding of what we now call the cell theory have been monumental. Observations under the light microscope kicked off the journey, but it was the development of the electron microscope that revealed intricate details like organelles and complex biochemistry, leading to a revolution in cellular biology and significantly enhancing the understanding of cellular processes.

Answer 2

The statements of the old cell theory are:
1. All organisms are composed of cells
2. The cell is the basic unit of life
3. Cells are produced from existing cells

The modern cell theory's statements are:
1. The cell contains hereditary information which is passed to daughter cells
2. All cells are basically the same in composition and activity
3. All basic functions occur in cells
4. Cell activities depend on intracellular structures

As is visible from the statements, the old cell theory was not as detailed and lacked the understanding of the function, structure and behavior of cells that the current theory possesses. This difference has come about after years of research, through which scientists understood the functions of cells and elaborated on the theory's statements.