Argument
Cell (biology)
Overview
The cell is the basic structural and functional unit of all forms of life or organisms. The term comes from the Latin word cellula meaning 'small room'. A biological cell basically consists of a semipermeable cell membrane enclosing cytoplasm that contains genetic material. Most cells are only visible under a microscope. Except for highly-differentiated cell types (examples include red blood cells and gametes) most cells are capable of replication, and protein synthesis. Some types of cell are motile. Cells emerged on Earth about four billion years ago.
All organisms are grouped into prokaryotes and eukaryotes. Prokaryotes are single-celled and include archaea and bacteria. Eukaryotes can be single-celled or multicellular. Single-celled eukaryotes include most protists, some species of fungi (yeasts), and some species of algae. Multicellular eukaryotes include animals, plants, some species of fungi, and some species of algae. All multicellular organisms are made up of many different types of cell. The diploid cells that make up the body of an animal or plant are known as somatic cells, which excludes the haploid gametes.
Prokaryotes lack a membrane-bound nucleus and have a nucleoid instead. In eukaryotic cells, the nucleus is enclosed in the nuclear membrane. Eukaryotic cells contain other membrane-bound organelles such as mitochondria, which provide energy for cell functions, and chloroplasts, in plants that create sugars by photosynthesis. Other membrane-less organelles may be proteinaceous, such as the ribosomes present (though different) in both groups. A unique membrane-bound prokaryotic organelle, the magnetosome has been discovered in magnetotactic bacteria.
Cells were discovered by Robert Hooke in 1665, who named them after their resemblance to cells in a monastery. Cell theory, developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all organisms, and that all cells come from pre-existing cells.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
In the original texts
Passages from public-domain books where Cell (biology) is discussed.
§ 74c. With the hypothesis, now general, that the nucleus or kernel of a cell is its essential part, there has not unnaturally grown up the dogma that it is always present; but there is reason to think that the evidence is somewhat strained to justify this dogma. In the first place, beyond the cases in which the nucleus, though ordinarily invisible, is said to have been rendered visible by a re-agent, there are…
Herbert Spencer, The Principles of Biology, Volume 1
names the idea; a chapter is titled for it; states what it is; opens on it
The process of aggregation is a vital one; by which I mean that the contents of the cells must be alive and uninjured to be thus affected, and they must be in an oxygenated condition for the transmission of the process at the proper rate. Some tentacles in a drop of water were strongly pressed beneath a slip of glass; many of the cells were ruptured, and pulpy matter of a purple colour, with granules of all sizes…
Charles Darwin, Insectivorous Plants
names the idea; a chapter is titled for it; opens on it
But, as we sometimes see half an anther or a small portion of a filament becoming petali-form, or parts or mere stripes of the calyx assuming the colour and texture of the corolla, it is probable that with petals the gemmules of each cell are not aggregated together into a compound gemmule, but are free and separate. Even in so simple a case as that of a perfect cell, with its protoplasmic contents, nucleus…
Charles Darwin, The Variation of Animals and Plants under Domestication
names the idea; states what it is; opens on it
There is, however, among the cells one central or pontifical one to which _our_ consciousness is attached. But the events of all the other cells physically influence this arch-cell; and through producing their joint effects on it, these other cells may be said to 'combine.' The arch-cell is, in fact, one of those 'external media' without which we saw that no fusion or integration of a number of things can occur. The…
William James, The Principles of Psychology, Volume 1
names the idea; states what it is
The influence of atomicity was not limited to chemistry. The living cell is to biology what the electron and the proton are to physics. Apart from cells and from aggregates of cells there are no biological phenomena. The cell theory was introduced into biology contemporaneously with, and independently of, Dalton’s atomic theory. The two theories are independent exemplifications of the same idea of ‘atomism.’ The…
Alfred North Whitehead, Science and the modern world
names the idea; states what it is
Philosophers who discussed Cell (biology)
Related ideas
- Animal
- Homeostasis
- Latin
- Life
- Virus
- Abiogenesis
- Molecule
- Organism
- Mutation
- Microorganism
- Species
- Oxygen
- Pharmacology
- Humboldt University of Berlin
- Pathogen
- Nature (journal)
- DNA
- RNA world
Place in the tradition
Part of Holism.