Топ-100 ★ Life - Life, Biological organisation, Carbon-based life, Chi
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★ Life - Life, Biological organisation, Carbon-based life, Chirality, Coleridges theory of life, extension ..




                                               

Life

Life is a characteristic that distinguishes individuals who have biological processes such as signaling and self-sustaining processes from those that do not, either because these functions have ceased, or because they never had such functions and are inanimate. There are various forms of life, such as plants, animals, fungi, Protista, archaea, and bacteria. Biology is the science concerned with the study of life. Currently there is no consensus on the definition of life. One of the most popular definitions is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to the environment, respond to stimuli, reproduce and develop. Other definitions sometimes include such cell-free viruses and viroid. Abiogenesis is the natural process of life arising from nonliving matter such as simple organic compounds. The prevailing scientific hypothesis is that the transition from inanimate to living beings not an isolated event, but a process of gradual increase of difficulty. Life on Earth first appeared to 4.28 billion years ago, soon after the formation of the ocean 4.41 billion years ago, soon after the formation of the Earth 4.54 billion years ago. The earliest known life forms are microorganisms bacteria. Researchers generally believe that the current life on Earth descends from an RNA world, RNA although life may not be the first life on earth. Classic 1952 the experiment the Miller–Urey and similar studies have shown that most amino acids, the chemical components of proteins in all living organisms, can be synthesized from inorganic compounds under conditions designed to replicate those of the early Earth. Complex organic molecules occur in the Solar system and in interstellar space, and these molecules can be provided source material for the development of life on Earth. Since its original inception, life on Earth has changed the environment on a geological time scale, but it is also adapted to survive in the ecosystems and conditions. Some microorganisms, called extremophiles, can thrive in physical or geochemical extreme conditions that are detrimental to most other life forms on Earth. Cell is structural and functional unit of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed in a membrane and contain many biomolecules, such as proteins and nucleic acids. Cells reproduce by cell division in which parent cell divides into two or more daughter cells. In the past there have been many attempts to define what is meant by "life" through outdated concepts such as odic force, hylomorphism, spontaneous generation and vitalism, which is already refuted by biological discoveries. Aristotle was the first person to classify organisms. Later, Carl Linnaeus introduced his binomial nomenclature for the classification of species. The result was a new groups and categories of life detected, such as cells and microorganisms, causing dramatic changes in the structure of relationships between living organisms. Although currently known only on Earth, life can not be limited, and many scientists suggest the existence of extraterrestrial life. Artificial life is a computer simulation or human-made reconstruction of any aspect of life, which is often used to study systems associated with natural life. Death is the cessation of all biological functions that maintain the organism, and as such, it is the end of his life. Extinction is a term that describes the dying out of a group or taxon, usually species. Fossils are the preserved remains or traces of living organisms.

                                               

Biological organisation

Biological organization is the hierarchy of complex biological structures and systems that define life using a local approach. The traditional hierarchy, as described below, extends from atoms to biospheres. At higher levels this scheme is often called the concept of environmental organizations, or as a field, a hierarchical environment. Each level in the hierarchy represents an increase in organizational complexity, with each "object" primarily consists of the previous levels of the base. The basic principle of the organization is the concept of emergence - the properties and functions found at a hierarchical level, there is no relationship at lower levels. Biological organization of life is the basis for many research areas, especially in the field of medicine. Without this necessary degree of organization, it would be much harder and probably impossible - to apply the study of the effects of various physical and chemical phenomena to diseases and physiological functioning of the body. For example, in areas such as cognitive and behavioral neuroscience could not exist if the brain is not composed of specific types of cells, and basic concepts of pharmacology could not exist if it was not known that changes at the cellular level can affect the entire body. These applications apply to environmental levels. For example, DDTs direct insecticidal action takes place at the subcellular level, but affects higher levels up to several ecosystems. Theoretically, a change in one atom could change the entire biosphere.

                                               

Carbon-based life

Carbon is the main component of all known forms of life on Earth, is approximately 45-50% of the dry biomass. Carbon compounds occur in nature in great abundance on Earth. Complex biological molecules almost always consist of atoms of carbon bonded with other elements, especially oxygen and hydrogen and also nitrogen, phosphorus and sulfur. Because it is lightweight and relatively small in size, the carbon molecules of enzymes is easy to manipulate. It is often assumed in astrobiology that if life exists elsewhere in the Universe, it will also be carbon-based. Critics refer to this assumption as carbon chauvinism.

                                               

Chirality

Chirality is a property of asymmetry important in several branches of science. The word "chirality" comes from the Greek χειρ, "hand", a familiar chiral object. Object or system is chiral if it differs from its mirror image, that is, it can not be imposed on him. Conversely, the mirror image achiral object, such as a sphere, cannot be separated from the object. A chiral object and its mirror image are called enantiomorphs Greek "opposite forms" or, when referring to molecules, enantiomers. Not a chiral object is called achiral sometimes amphichiral and can be superimposed on its mirror image. The term was first used by Lord Kelvin in 1893 in the second Robert Boyle lecture at the Oxford University Junior scientific club which was published in 1894: I call any geometrical figure or group of points chiral and say it has chirality, if its image in a plane mirror, ideally realized, cannot be brought to coincide with itself. Human hands are perhaps the most universally recognized example of chirality. The left hand is not superimposable mirror image of the right hand, no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide in all axes. This difference in symmetry becomes obvious if someone attempts to shake the hand of the person using your left hand, or left hand glove is placed on right hand. In mathematics chirality is the property of a shape that is not identical to its mirror image.

                                               

Coleridge's theory of life

Romance rose largely because attempts to understand not only inertia, but also a vital character. Romantic works in the field of art and romance of medicine were a response to a General lack of application of the method of inertial science to uncover the fundamental laws and principles of operant life of nature. German romantic science and medicine aim to understand the nature and principle of life, identified John hunter, in contrast to matter itself using Johann Friedrich Blumenbachs Bildungstrieb and romantic medicine Lebenskraft, as well as Roschlaubs development of the Brunonian system of medicine, the system of John brown, in his excitement theory of life, working also from Schellings Naturphilosophie, Goethes work in morphology, and the first dynamic concept of physiology Richard Saumarez. However, it is in Samuel Taylor Coleridge, which we find life and life of nature most intensely and comprehensively studied, especially in its hints towards a more comprehensive theory of life, providing the basis for romantic philosophy, science, and medicine. Work is the key to understanding the relationship of romantic literature, and science.

                                               

Life extension

Life extension is the idea of extending human life, either modestly due to improvements in medicine – or drastically due to the increase in the maximum lifespan beyond it, as a rule, settled the limit of 125 years. The ability to achieve such radical changes, however, do not currently exist. Some researchers in this area, and "life promoters", "immortalists" or "longevists" those who wish to achieve longer lives themselves believe that future breakthroughs in tissue rejuvenation, stem cells, regenerative medicine, molecular repair, gene therapy, pharmaceuticals, and organs such as a replacement artificial organs or xenotransplantations will eventually enable humans to have an indefinite life agerasia through complete rejuvenation to a healthy young condition. Ethical implications if the life extension is a possibility, will be discussed by experts in bioethics. Sale allegedly anti-aging products such as supplements and hormone replacement is a lucrative global industry. For example, in the industry that promotes the use of hormones as treatment for consumers to slow or reverse the aging process in the U.S. market amounted to about $ 50 billion of revenue per year in 2009. The use of such products has not been proven to be effective or safe.

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