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phosphofructokinase ... phyi-mchod

phosphofructokinase: enzyme that is important in regulating the process of fermentation, by which one molecule of the simple sugar glucose is broken down to two molecules of pyruvic acid. The enzyme, ...
phospholipid: any member of a large class of fatlike, phosphorus-containing substances that play important structural and metabolic roles in living cells. The phospholipids, with the sphingolipids, the glycolipids, and the lipoproteins, ...
phosphor: solid material that emits light, or luminesces, when exposed to radiation such as ultraviolet light or an electron beam. Hundreds of thousands of phosphors have been synthesized, each one having ...
phosphor bronze: alloy of copper and tin that contains a trace of phosphorus. See bronze.
phosphorescence: emission of light from a substance exposed to radiation and persisting as an afterglow after the exciting radiation has been removed. Unlike fluorescence, in which the absorbed light is spontaneously ...
phosphoric acid: the most important oxygen acid of phosphorus, used to make phosphate salts for fertilizers. It is also used in dental cements, in the preparation of albumin derivatives, and in the ...
phosphorite: rock with a high concentration of phosphates in nodular or compact masses. The phosphates may be derived from a variety of sources, including marine invertebrates ...
phosphorous acid: one of several oxygen acids of phosphorus, used as reducing agent in chemical analysis. It is a colourless or yellowish crystalline substance (melting point about 73° C, or 163° F) ...
phosphorus: nonmetallic chemical element of the nitrogen family (Group Va of the periodic table).
phosphorus cycle: circulation of phosphorus in various forms through nature. Of all the elements recycled in the biosphere, phosphorus is the scarcest and therefore the one most limiting in any given ecological ...
phosphorus deficiency: condition in which phosphorus is insufficient or is not utilized properly. Phosphorus is a mineral that is vitally important to the normal metabolism of numerous compounds and (in solution) an ...
phosphorylation: in chemistry, the addition of a phosphoryl group (PO₃^2-) to an organic compound. The process by which much of the energy in foods is conserved and made available to the ...
Photian Schism: a 9th-century-AD controversy between Eastern and Western Christianity that was precipitated by the opposition of the Roman pope to the appointment by the Byzantine emperor Michael III of the lay ...
photic zone: surface layer of the ocean that receives sunlight. The uppermost 80 m (260 feet) or more of the ocean, which is sufficiently illuminated to permit photosynthesis by phytoplankton and plants, ...
Photisarath: also spelled Phothisarath, Phothisarat, or Potisarat ruler (1520-47) of the Lao kingdom of Lan Xang whose territorial expansion embroiled Laos in the warfare that swept mainland Southeast Asia in the ...
Photius, Saint: patriarch of Constantinople (858-867 and 877-886), defender of the autonomous traditions of his church against Rome and leading figure of the 9th-century Byzantine renascence.
photo-ionization: the interaction of electromagnetic radiation with matter resulting in the dissociation of that matter into electrically charged particles. The simplest example, the photoelectric effect (q.v.), occurs when light shines on ...
Photo-Secession: the first influential group of American photographers that worked to have photography accepted as a fine art. Led by Alfred Stieglitz, the group also included Edward Steichen, Clarence H. White, ...
photocathode: an element of a photoelectric cell (q.v.) that emits electrons when struck by light, making possible the flow of electric current through the device. A substance often used for photocathodes ...
photochemical equivalence law: fundamental principle relating to chemical reactions induced by light, which states that for every quantum of radiation that is absorbed, one molecule of the substance reacts. A quantum is a ...
photochemical reaction: any type of chemical process initiated by the absorption of energy in the form of visible, infrared, or ultraviolet radiation. The immediate consequence of this absorption is called the primary ...
photocomposition: method of assembling or setting type by photographing characters on film from which printing plates are made. The characters are developed as photographic positives on film or light-sensitive paper from ...
photoconductivity: that portion of the ability of a material to allow an electric current to flow in it that is affected by exposure to light, frequently used to detect and measure ...
photocopying machine: any device for producing copies of text or graphic material by the use of light, heat, chemicals, or electrostatic charges. The need for a process other than wet photographic reproduction ...
photodisintegration: in physics, nuclear reaction in which the absorption of high-energy electromagnetic radiation (a gamma-ray photon) causes the absorbing nucleus to change to another species by ejecting a subatomic particle, such ...
photodynamism: conversion of certain substances in the skin of animals into other substances by the action of light. The resultant compounds may be beneficial (e.g., vitamin D), but in some cases ...
photoelasticity: the property of some transparent materials, such as glass or plastic, while under stress, to become doubly refracting (i.e., a ray of light will split into two rays at entry). ...
photoelectric cell: an electron tube with a photosensitive cathode that emits electrons when illuminated and an anode for collecting the emitted electrons. Various cathode materials are sensitive to specific spectral regions, such ...
photoelectric effect: phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a ...
photoengraving: any of several processes for producing printing plates by photographic means. In general, a plate coated with a photosensitive substance is exposed to an image, usually on film; the plate ...
photogram: shadowlike photographic image made on paper without the use of a negative or a camera. It is made by placing objects between light-sensitive paper or film and a light source. ...
photogrammetry: technique that uses photographs for mapmaking and surveying. As early as 1851 the French inventor Aime Laussedat perceived the possibilities of the application of the newly invented camera to mapping, ...
photography, history of: method of recording the image of an object through the action of light, or related radiation, on a light-sensitive material. The word, derived from the Greek photos ...
photography, technology of: equipment, techniques, and processes used in the production of photographs.
photoluminescence: emission of light from a substance as a result of absorption of electromagnetic radiation; such a substance is called a phosphor (q.v.), and the emitted light usually has a longer ...
photolysis: chemical process by which molecules are broken down into smaller units through the absorption of light.
photometer: device that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Such devices are generally transducers that convert an electric current ...
photometry: in astronomy, the measurement of the brightness of stars and other celestial objects (nebulae, galaxies, planets, etc.). Such measurements can yield large amounts of information on the objects' structure, temperature, ...
photomicrography: photography of objects under a microscope. Such opaque objects as metal and stone may be ground smooth, etched chemically to show their structure, and photographed by reflected light with a ...
photomontage: composite photographic image made either by pasting together individual prints or parts of prints, by successively exposing individual images onto a single paper, or by exposing the component images simultaneously ...
photomultiplier tube: electron multiplier tube that utilizes the multiplication of electrons by secondary emission to measure low light intensities. It is useful in television camera tubes, in astronomy to measure intensity of ...
photon: minute energy packet of electromagnetic radiation. The concept originated (1905) in Einstein's explanation of the photoelectric effect, in which he proposed the existence of discrete energy packets during the transmission ...
photoperiodism: the functional or behavioral response of an organism to changes of duration in daily, seasonal, or yearly cycles of light and darkness. Photoperiodic reactions can be reasonably predicted, but temperature, ...
photophore: light-emitting organ present in fireflies and certain other bioluminescent animals. Photophores are glandular in origin and produce light by a chemical reaction. Photophores vary in size and form but often ...
photoprotein: in biochemistry, any of several proteins that give off light upon combination with oxygen, hydrogen peroxide, or other oxidizing agents. Unlike the oxidation of luciferin, the production of light by ...
photoreception: any of the biological responses of organisms to stimulation by light. Most organisms, including humans, respond to visible light; some react to wavelengths of light not seen by humans; and ...
photorecovery: restoration to the normal state, by the action of visible light, of the deoxyribonucleic acid composing the hereditary material in animal skin cells and plant epidermal cells damaged by exposure ...
photosensitization: the process of initiating a reaction through the use of a substance capable of absorbing light and transferring the energy to the desired reactants. The technique is commonly employed in ...
photosphere: visible surface of the Sun, about 400 kilometres (250 miles) thick, from which is emitted most of the Sun's light that reaches the Earth directly. Light generated deeper in the ...
photosynthesis: the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, ...
photovoltaic effect: process in which two dissimilar materials in close contact produce an electrical voltage when struck by light or other radiant energy. Light striking crystals such as silicon or germanium, in ...
Phra Nakhon: section of Bangkok Metropolis, Thailand's capital and largest city, on the east bank of the Mae Nam (river) Chao Phraya. It was a changwat (province) until 1972, when it was ...
Phraates II: king of Parthia (reigned c. 138-128 BC), the son and successor of Mithradates I.
Phraates III: king of Parthia (reigned 70-58/57 BC), the son and successor of Sanatruces (Sinatruces).
Phraates IV: king of Parthia (reigned c. 37-2 BC) who murdered his father, Orodes II, and his brothers to secure the throne.
Phraates V: king of Parthia (reigned c. 2 BC-c. AD 4), the son and successor of Phraates IV.
Phrae: town in the mountainous northern region of Thailand. It is located on the Yom River and the Sukhothai-Nan road in a historic region with many temples and ruins. Teak lumbering ...
Phraortes: king of Media from 675 to 653 BC. Phraortes, who was known by that name as a result of the writings of the 5th-century-BC Greek historian Herodotus, was originally a ...
phrenology: the study of the conformation of the skull as indicative of mental faculties and traits of character, especially according to the hypotheses of Franz-Joseph Gall (1758-1828), a Viennese doctor, and ...
Phrygia: ancient district in west-central Anatolia, named after a people whom the Greeks called Phryges and who dominated Asia Minor between the Hittite collapse (12th century BC) and the Lydian ascendancy ...
Phrygian cap: soft felt or wool conical headdress fitting closely around the head and characterized by a pointed crown that curls forward. It originated in the ancient country of Phrygia in Asia ...
Phrygian language: ancient Indo-European language of west-central Anatolia, preserved in two distinct sets of texts. The first, representing Old Phrygian, consists of mostly cultic inscriptions on stone in an alphabet related to ...
Phrygian mode: in music, third of the eight medieval church modes. See church mode.
Phryne: famous Greek courtesan. Because of her sallow complexion she was called by the Greek name for "toad."
Phrynichus: Athenian poet of the Old Comedy.
Phrynichus: Athenian tragic poet, an older contemporary of Aeschylus. He was the earliest tragedian of whose work some conception can be formed.
Phrynichus Arabius: grammarian and rhetorician who produced Sophistike Paraskeue ("A Grounding in Sophistic"), of which a few fragments and a summary by Photius survive, and an Attikistes, extant in an abridged form, ...
phthalic acid: colourless, crystalline organic compound ordinarily produced and sold in the form of its anhydride. The annual production of phthalic anhydride exceeded 1,000,000 metric tons in the late 20th century; most ...
Phu Quoc Island: island in the Gulf of Thailand, belonging to Vietnam. Lying 7 miles (11 km) off the Cambodian coast south of Bok Kou (formerly Bokor) and 43 miles (69 km) west ...
Phuket: city and island, southern Thailand. The island lies in the Andaman Sea, off the west coast of peninsular Thailand. Phuket city, located in the southeastern portion of the island, is ...
Phulbani: city, central Orissa state, eastern India. It is located about 22 miles (35 km) southwest of the Mahanadi River. The city is relatively modern, although small in size. Its industries ...
phur-bu: (Tibetan: "peg," or "nail"), a ritual dagger used in the Tantric (esoteric) rites of Tibetan Buddhism to exorcise evil. The dagger has a three-sided blade and a hilt that terminates ...
Phuthaditjhaba: town, northeastern Free State province, South Africa. It was the capital of the territory formerly designated by South Africa as the nonindependent black state of Qwaqwa. Phuthaditjhaba lies near the ...
Phycomycetes: in general, any of the six classes of lower fungi, or algal fungi: Chytridiomycetes, Hyphochytridiomycetes, Plasmodiophoromycetes, Oomycetes, Zygomycetes, and Trichomycetes (qq.v.). The term had class rank in earlier classification systems.
Phyfe, Duncan: Scottish-born American furniture designer, a leading exponent of the Neoclassical style, sometimes considered the greatest of all American cabinetmakers.
phyi-mchod: in Tibetan Buddhist ceremonies, the eight offerings of external worship, presented before the tranquil deities. They are basically the eight ways of honouring a distinguished guest-by offering water for drinking, ...