www.saw.com www.stellarartwars.co.uk Metaphysics From Wikipedia, the free encyclopedia For other uses, see Metaphysics (disambiguation). Philosophy Left to right: Plato, Kant, Nietzsche Plato – Kant – Nietzsche Philosophers Aestheticians Epistemologists Ethicists Logicians Metaphysicians Social and political philosophers Traditions Analytic Continental Pragmatism Eastern Islamic Platonic Scholastic Periods Ancient Medieval Modern Contemporary Literature Aesthetics Epistemology Ethics Logic Metaphysics Political philosophy Branches Aesthetics Epistemology Ethics Legal philosophy Logic Metaphysics Political philosophy Social philosophy Lists Index Outline Years Problems Publications Theories Glossary Philosophers Portal icon Philosophy portal v t e Metaphysics is a traditional branch of philosophy concerned with explaining the fundamental nature of being and the world that encompasses it,[1] although the term is not easily defined.[2] Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:[3] Ultimately, what is there? What is it like? A person who studies metaphysics is called a metaphysicist[4] or a metaphysician.[5] The metaphysician attempts to clarify the fundamental notions by which people understand the world, e.g., existence, objects and their properties, space and time, cause and effect, and possibility. A central branch of metaphysics is ontology, the investigation into the basic categories of being and how they relate to each other. Another central branch of metaphysics is cosmology, the study of the origin, fundamental structure, nature, and dynamics of the universe. Some include Epistemology as another central focus of metaphysics, but this may be questioned. Prior to the modern history of science, scientific questions were addressed as a part of metaphysics known as natural philosophy. Originally, the term "science" (Latin scientia) simply meant "knowledge". The scientific method, however, transformed natural philosophy into an empirical activity deriving from experiment unlike the rest of philosophy. By the end of the 18th century, it had begun to be called "science" to distinguish it from philosophy. Thereafter, metaphysics denoted philosophical enquiry of a non-empirical character into the nature of existence.[6] Some philosophers of science, such as the neo-positivists, say that natural science rejects the study of metaphysics, while other philosophers of science strongly disagree. DNA From Wikipedia, the free encyclopedia (Redirected from Dna) For a non-technical introduction to the topic, see Introduction to genetics. For other uses, see DNA (disambiguation). The structure of the DNA double helix. The atoms in the structure are colour-coded by element and the detailed structure of two base pairs are shown in the bottom right. The structure of part of a DNA double helix Deoxyribonucleic acid (Listeni/diˌɒksiˌraɪbɵ.njuːˌkleɪ.ɨk ˈæsɪd/; DNA) is a molecule that carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses. DNA is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides. Each nucleotide is composed of a nitrogen-containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a monosaccharide sugar called deoxyribose and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. According to base pairing rules (A with T, and C with G), hydrogen bonds bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA. DNA stores biological information. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information. Biological information is replicated as the two strands are separated. A significant portion of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences. The two strands of DNA run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes biological information. Under the genetic code, RNA strands are translated to specify the sequence of amino acids within proteins. These RNA strands are initially created using DNA strands as a template in a process called transcription.

• published: 17 Jul 2015
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