Who was the first person to see cells under the microscope and give them a name

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The cell theory, or cell doctrine, states that all organisms are composed of similar units of organization, called cells. The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. The idea predates other great paradigms of biology including Darwin’s theory of evolution (1859), Mendel’s laws of inheritance (1865), and the establishment of comparative biochemistry (1940).

First Cells Seen in Cork

While the invention of the telescope made the Cosmos accessible to human observation, the microsope opened up smaller worlds, showing what living forms were composed of. The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. Hooke’s description of these cells was published in Micrographia. The cell walls observed by Hooke gave no indication of the nucleus and other organelles found in most living cells. The first man to witness a live cell under a microscope was Anton van Leeuwenhoek, who in 1674 described the algae Spirogyra. Van Leeuwenhoek probably also saw bacteria.

Formulation of the Cell Theory

In 1838, Theodor Schwann and Matthias Schleiden were enjoying after-dinner coffee and talking about their studies on cells. It has been suggested that when Schwann heard Schleiden describe plant cells with nuclei, he was struck by the similarity of these plant cells to cells he had observed in animal tissues. The two scientists went immediately to Schwann’s lab to look at his slides. Schwann published his book on animal and plant cells (Schwann 1839) the next year, a treatise devoid of acknowledgments of anyone else’s contribution, including that of Schleiden (1838). He summarized his observations into three conclusions about cells:

The cell is the unit of structure, physiology, and organization in living things.
The cell retains a dual existence as a distinct entity and a building block in the construction of organisms.
Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).

We know today that the first two tenets are correct, but the third is clearly wrong. The correct interpretation of cell formation by division was finally promoted by others and formally enunciated in Rudolph Virchow’s powerful dictum, Omnis cellula e cellula,: “All cells only arise from pre-existing cells”.

Modern Cell Theory

All known living things are made up of cells.
The cell is structural & functional unit of all living things.
All cells come from pre-existing cells by division. (Spontaneous Generation does not occur).
Cells contains hereditary information which is passed from cell to cell during cell division.
All cells are basically the same in chemical composition.
All energy flow (metabolism & biochemistry) of life occurs within cells.

As with the rapid growth of molecular biology in the mid-20th century, cell biology research exploded in the 1950’s. It became possible to maintain, grow, and manipulate cells outside of living organisms. The first continuous cell line to be so cultured was in 1951 by George Otto Gey and coworkers, derived from cervical cancer cells taken from Henrietta Lacks, who died from her cancer in 1951. The cell line, which was eventually referred to as HeLa cells, have been the watershed in studying cell biology in the way that the structure of DNA was the significant breakthrough of molecular biology.

In an avalanche of progress in the study of cells, the coming decade included the characterization of the minimal media requirements for cells and development of sterile cell culture techniques. It was also aided by the prior advances in electron microscopy, and later advances such as the development of transfection methods, the discovery of green fluorescent protein in jellyfish, and discovery of small interfering RNA (siRNA), among others.

The study of the structure and function of cells continues today, in a branch of biology known as cytology. Advances in equipment, including cytology microscopes and reagents, have allowed this field to progress, particularly in the clinical setting.

A Timeline

1595 – Jansen credited with 1st compound microscope
1655 – Hooke described ‘cells’ in cork.
1674 – Leeuwenhoek discovered protozoa. He saw bacteria some 9 years later.
1833 – Brown descibed the cell nucleus in cells of the orchid.
1838 – Schleiden and Schwann proposed cell theory.
1840 – Albrecht von Roelliker realized that sperm cells and egg cells are also cells.
1856 – N. Pringsheim observed how a sperm cell penetrated an egg cell.
1858 – Rudolf Virchow (physician, pathologist and anthropologist) expounds his famous conclusion: omnis cellula e cellula, that is cells develop only from existing cells [cells come from preexisting cells]
1857 – Kolliker described mitochondria.
1879 – Flemming described chromosome behavior during mitosis.
1883 – Germ cells are haploid, chromosome theory of heredity.
1898 – Golgi described the golgi apparatus.
1938 – Behrens used differential centrifugation to separate nuclei from cytoplasm.
1939 – Siemens produced the first commercial transmission electron microscope.
1952 – Gey and coworkers established a continuous human cell line.
1955 – Eagle systematically defined the nutritional needs of animal cells in culture.
1957 – Meselson, Stahl and Vinograd developed density gradient centrifugation in cesium chloride solutions for separating nucleic acids.
1965 – Ham introduced a defined serum-free medium. Cambridge Instruments produced the first commercial scanning electron microscope.
1976 – Sato and colleagues publish papers showing that different cell lines require different mixtures of hormones and growth factors in serum-free media.
1981 – Transgenic mice and fruit flies are produced. Mouse embryonic stem cell line established.
1995 – Tsien identifies mutant of GFP with enhanced spectral properties
1998 – Mice are cloned from somatic cells.
1999 – Hamilton and Baulcombe discover siRNA as part of post-transcriptional gene silencing (PTGS) in plants

References:

What is this incredible object? Would it surprise you to learn that it is a human cell? The cell is actually too small to see with the unaided eye. It is visible here in such detail because it is being viewed with a very powerful microscope. Cells may be small in size, but they are extremely important for life. Like all other living things, you are made of cells. Cells are the basis of life, and without cells, life as we know it would not exist. You will learn more about these amazing building blocks of life when you read this section.

Figure \(\PageIndex{1}\): Healthy human T-cell

If you look at a living matter with a microscope — even a simple light microscope — you will see that it consists of cells. Cells are the basic units of the structure and function of living things. They are the smallest units that can carry out the processes of life. All organisms are made up of one or more cells, and all cells have many of the same structures and carry out the same basic life processes. Knowing the structure of cells and the processes they carry out is necessary to understanding life itself.

The first time the word cell was used to refer to these tiny units of life was in 1665 by a British scientist named Robert Hooke. Hooke was one of the earliest scientists to study living things under a microscope. The microscopes of his day were not very strong, but Hooke was still able to make an important discovery. When he looked at a thin slice of cork under his microscope, he was surprised to see what looked like a honeycomb. Hooke made the drawing in the figure below to show what he saw. As you can see, the cork was made up of many tiny units, which Hooke called cells.

Soon after Robert Hooke discovered cells in cork, Anton van Leeuwenhoek in Holland made other important discoveries using a microscope. Leeuwenhoek made his own microscope lenses, and he was so good at it that his microscope was more powerful than other microscopes of his day. In fact, Leeuwenhoek’s microscope was almost as strong as modern light microscopes. Using his microscope, Leeuwenhoek was the first person to observe human cells and bacteria.

Figure \(\PageIndex{2}\): Robert Hooke sketched these cork cells as they appeared under a simple light microscope.

By the early 1800s, scientists had observed the cells of many different organisms. These observations led two German scientists, named Theodor Schwann and Matthias Jakob Schleiden, to propose that cells are the basic building blocks of all living things. Around 1850, a German doctor named Rudolf Virchow was studying cells under a microscope when he happened to see them dividing and forming new cells. He realized that living cells produce new cells through division. Based on this realization, Virchow proposed that living cells arise only from other living cells.

The ideas of all three scientists — Schwann, Schleiden, and Virchow — led to cell theory, which is one of the fundamental theories unifying all of biology. Cell theory states that:

All organisms are made of one or more cells.
All the life functions of organisms occur within cells.
All cells come from already existing cells.

Starting with Robert Hooke in the 1600s, the microscope opened up an amazing new world — the world of life at the level of the cell. As microscopes continued to improve, more discoveries were made about the cells of living things. However, by the late 1800s, light microscopes had reached their limit. Objects much smaller than cells, including the structures inside cells, were too small to be seen with even the strongest light microscope.

Then, in the 1950s, a new type of the microscope was invented. Called the electron microscope, it used a beam of electrons instead of light to observe extremely small objects. With an electron microscope, scientists could finally see the tiny structures inside cells. In fact, they could even see individual molecules and atoms. The electron microscope had a huge impact on biology. It allowed scientists to study organisms at the level of their molecules and led to the emergence of the field of cell biology. With the electron microscope, many more cell discoveries were made. Figure \(\PageIndex{3}\) shows how the cell structures called organelles appear when scanned by an electron microscope.

Figure \(\PageIndex{3}\): An electron microscope produced this image of the structures inside a cell.

Although cells are diverse, all cells have certain parts in common. These parts include a plasma membrane, cytoplasm, ribosomes, and DNA.

The plasma membrane (also called the cell membrane) is a thin coat of phospholipids that surrounds a cell. It forms the physical boundary between the cell and its environment, so you can think of it as the “skin” of the cell.
Cytoplasm refers to all of the cellular material inside the plasma membrane. The Cytoplasm is made up of a watery substance called cytosol and contains other cell structures such as ribosomes.
Ribosomes are structures in the cytoplasm where proteins are made.
DNA is a nucleic acid found in cells. It contains the genetic instructions that cells need to make proteins.

These parts are common to all cells, from organisms as different as bacteria and human beings. How did all known organisms come to have such similar cells? The similarities show that all life on Earth has a common evolutionary history.

https://bio.libretexts.org/link?16740#Explore_More

To learn more about cell theory, and its history, watch the video below.