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The term bioethics ( Greek bios, "life"; ethos, "moral nature, behavior" [ 1]) was coined in 1927 by Fritz Jahr in an article about a "bioethical imperative" regarding the use of animals and plants in scientific research. [ 2] In 1970, the American biochemist, and oncologist Van Rensselaer Potter used the term to describe the relationship ...
Biological applications of bifurcation theory provide a framework for understanding the behavior of biological networks modeled as dynamical systems. In the context of a biological system, bifurcation theory describes how small changes in an input parameter can cause a bifurcation or qualitative change in the behavior of the system.
An effector is the target acted on, to bring about the change back to the normal state. At the cellular level, effectors include nuclear receptors that bring about changes in gene expression through up-regulation or down-regulation and act in negative feedback mechanisms. An example of this is in the control of bile acids in the liver. [4]
Limiting factor. A limiting factor is a variable of a system that causes a noticeable change in output or another measure of a type of system. The limiting factor is in a pyramid shape of organisms going up from the producers to consumers and so on. A factor not limiting over a certain domain of starting conditions may yet be limiting over ...
The upper DNA molecule differs from the lower DNA molecule at a single base-pair location (a G/A polymorphism). In genetics and bioinformatics, a single-nucleotide polymorphism ( SNP / snɪp /; plural SNPs / snɪps /) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the ...
A number of examples of positive feedback systems may be found in physiology. One example is the onset of contractions in childbirth, known as the Ferguson reflex. When a contraction occurs, the hormone oxytocin causes a nerve stimulus, which stimulates the hypothalamus to produce more oxytocin, which increases uterine contractions.
Think of, say, intelligent design, Holocaust denial, ancient astronaut hypothesis, homoeopathy, the anti-vaccine movement, astrology, or climate change scepticism. Because there are different forms of pseudoscience, one cannot rule out the possibility that different criteria are needed to distinguish them from science.
Gene expression plays a crucial role in determining the phenotypes of organisms. The level of gene expression can affect the phenotype of an organism. For example, if a gene that codes for a particular enzyme is expressed at high levels, the organism may produce more of that enzyme and exhibit a particular trait as a result. On the other hand ...