In 1838, Matthias Schleiden, a German botanist, examined a large number of plants and observed that all plants are composed of different kinds of cells which form the tissues of the plant. At about the same time, Theodore Schwann (1839), a German Zoologist, studied different types of animal cells and reported that cells had a thin outer layer which is today known as the ‘plasma membrane’. He also concluded, based on his studies on plant tissues, that the presence of cell wall is a unique character of the plant cells. On the basis of this, Schwann proposed the hypothesis that the bodies of animals and plants are composed of cells and products of cells.
Development of Cell Theory
Scientists wanted to understand how plants and animals are built. By observing different plants and animals under microscopes, they discovered that cells are the basic building blocks of living organisms. Two important scientists, Matthias Schleiden and Theodor Schwann, helped develop the cell theory.
1. Matthias Schleiden (1838)
Matthias Schleiden was a German botanist. A botanist is a scientist who studies plants.
In 1838, Schleiden studied many different plants using a microscope. He observed that plants are made up of different kinds of cells. These cells are organised into groups that form tissues.
Think of a plant as a building made from tiny building blocks. The cells are the building blocks, and groups of cells form tissues that help the plant perform different jobs.
Remember
Matthias Schleiden (1838) — concluded that plants are composed of different kinds of cells.
2. Theodor Schwann (1839)
Theodor Schwann was a German zoologist. A zoologist is a scientist who studies animals.
In 1839, Schwann studied different types of animal cells. He observed that cells have a thin outer covering, now called the plasma membrane.
The plasma membrane acts like a boundary around the cell. It separates the inside of the cell from its surroundings and controls the movement of many substances into and out of the cell.
3. Cell Wall in Plant Cells
Schwann also considered Schleiden’s observations about plant tissues. Plant cells have a cell wall outside their plasma membrane. The cell wall provides support, protection, and shape to plant cells.
Animal cells do not have a cell wall. They have a plasma membrane as their outer boundary.
| Feature | Plant cell | Animal cell |
|---|---|---|
| Plasma membrane | Present | Present |
| Cell wall | Present | Absent |
4. Schwann’s Hypothesis
Based on his studies and Schleiden’s observations, Schwann proposed that the bodies of plants and animals are made up of cells and products of cells.
Products of cells are materials made by cells. For example, plant cells produce materials that contribute to structures such as the cell wall.
This idea became an important part of the development of cell theory, which explains the importance of cells in living organisms.
Important Facts for NEET
- Matthias Schleiden (1838): Studied plants and concluded that they are composed of cells.
- Theodor Schwann (1839): Studied animal cells and described the plasma membrane.
- Cell wall: Present in plant cells but absent in animal cells.
- Schwann’s hypothesis: Plants and animals are composed of cells and products of cells.