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Biology is the scientific study of life. [1] [2] [3] It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. [1] [2] [3] For instance, all organisms are composed of at least one cell that processes hereditary information encoded in genes, which
Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. [1] [2] All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. [3] Cell biology is the study of the structural and functional ...
In evolutionary biology, a spandrel is a phenotypic trait that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection. Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper " The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the ...
Cell Biology in "The Biology Project" of University of Arizona. Centre of the Cell online; The Image & Video Library of The American Society for Cell Biology Archived 2011-06-10 at the Wayback Machine, a collection of peer-reviewed still images, video clips and digital books that illustrate the structure, function and biology of the cell.
The ribosome has two binding sites for tRNA. They are the aminoacyl site (abbreviated A), and the peptidyl site/ exit site (abbreviated P/E). Concerning the mRNA, the three sites are oriented 5' to 3' E-P-A, because ribosomes move toward the 3' end of mRNA. The A-site binds the incoming tRNA with the complementary codon on the mRNA.
The green box (central) may represent an evolutionary grade (paraphyletic), a group united by conservative anatomical and physiological traits rather than phylogeny. The flanking red and blue boxes are clades (i.e., complete monophyletic subtrees). A grade is a taxon united by a level of morphological or physiological complexity.
Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct grade of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs—with a distinct type of construction, which is to say a ...