Home > Cell (biology)
Cells in culture, stained for keratinThe cell is the structural and functional unit of all living organisms. Some organisms, such as bacteria, are unicellular, consisting of a single cell. Other organisms, such as humans, are multicellular, (humans have an estimated 100,000 billion = 1014 cells).
The cell theory, first developed in the 19th century, states that all organisms are composed of one or more cells; all cells come from preexisting cells; all vital functions of an organism occur within cells and that cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
The word cell comes from the Latin cella, a small room. The name was chosen by Robert Hooke because of the likeness he saw between cork cells and small rooms.
1 Overview
1.1 Properties of cells
Each cell is a self-contained and self-maintaining entity: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these activities.
All cells share several abilities:
- Reproduction by cell division.
- Metabolism, including taking in raw materials, building cell components, creating energyThis article is about the scientific concept. Energy use by humans is discussed in other articles''. Energy generally and qualitatively speaking, is the property (or the quantity of the property) of doing things or supplying power. The expressions energy molecules and releasing byproducts. The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy is derived from metabolic pathwayIn biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell, catalyzed by enzymes, and resulting in either the formation of a metabolic product to be used or stored by the cell ( metabolic sink), or the initiation of anos.
- Synthesisnucleus of the cell light blue , genes (DNA, dark blue are transcribed into RNA. This RNA is then subject to post-transcriptional modification and control, resulting in a mature mRNA red that is then transported out of the nucleus and into the cytoplasm p of proteinmyoglobin, showing coloured alpha helices. This protein was the first to have its structure solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, which led to them receiving a Nobel Prize in Chemistry. A protein is a complex,s, the functional workhorses of cells, such as enzymeAn enzyme is a protein, or protein complex, that catalyzes a chemical reaction. Like any catalyst, enzymes work by lowering the activation energy of a reaction, thus allowing the reaction to proceed to its steady state or completion much faster than it ots. A typical mammalianSubclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorp cell contains up to 10,000 different proteinmyoglobin, showing coloured alpha helices. This protein was the first to have its structure solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, which led to them receiving a Nobel Prize in Chemistry. A protein is a complex,s.
- Response to external and internal stimuli such as changes in temperature, pH or nutrient levels.
- Traffic of vesicles.
