3-hidroxi-3-metilglutaril-coencima ALos terpenos son el principal constituyente de los aceites esenciales de algunas plantas y flores, como el limonero y el naranjo. Los esteroides y esteroles son producidos a partir de terpenos precursores. Se tdrpenos clasifica en:. El pirofosfato de geranilo terpenos y esteroides wikipedia precursor de los monoterpenos. Por esta ruta se sintetizan principalmente sesquiterpenos, triterpenos y politerpenos.
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Los terpenos son el principal constituyente de los aceites esenciales de algunas plantas y flores, como el limonero y el naranjo. Los esteroides y esteroles son producidos a partir de terpenos precursores.
Se los clasifica en:. El pirofosfato de geranilo es precursor de los monoterpenos. Por esta ruta se sintetizan principalmente sesquiterpenos, triterpenos y politerpenos. Por esta ruta se sintetizan sobre todo monoterpenos, diterpenos y carotenoides. Algunos terpenos que se consideran como nutrientes: In its pure form it is a volatile liquid.
Isoprene is produced by plants, and its polymers are the main component of natural rubber. Williams named the compound in after obtaining it from thermal decomposition of natural rubber, isoprene is produced and emitted by many species of trees. Yearly production of emissions by vegetation is around million metric tons, half from tropical broadleaf trees. Isoprene is made through the methyl-erythritol 4-phosphate pathway in the chloroplasts of plants, one of the two end products of MEP pathway, dimethylallyl pyrophosphate, is catalyzed by the enzyme isoprene synthase to form isoprene.
This has led to the hypothesis that isoprene may protect plants against heat stress, emission of isoprene is also observed in some bacteria and this is thought to come from non-enzymatic degradations from DMAPP. Isoprene emission in plants is controlled both by the availability of substrate and by enzyme activity, isoprene is the most abundant hydrocarbon measurable in the breath of humans. The estimated production rate of isoprene in the body is 0.
Isoprene is common in low concentrations in many foods, isoprene emission appears to be a mechanism that trees use to combat abiotic stresses. In particular, isoprene has been shown to protect against moderate heat stress and it may also protect plants against large fluctuations in leaf temperature.
Isoprene is incorporated into and helps stabilize cell membranes in response to heat stress, isoprene also confers resistance to reactive oxygen species. The amount of isoprene released from isoprene-emitting vegetation depends on mass, leaf area, light. This is thought to add resistance to harsh environments in which many Archaea are found. The isoprene skeleton can be found in naturally occurring compounds called terpenes, terpenes can be viewed as multiples of isoprene subunits, and this perspective is the cornerstone of the isoprene rule.
Pinaceae — The Pinaceae are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales, Pinaceae are supported as monophyletic by their protein-type sieve cell plastids, pattern of proembryogeny, and lack of bioflavonoids. The family often forms the dominant component of boreal, coastal, one species, Pinus merkusii, grows just south of the equator in Southeast Asia.
Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California. Members of the family Pinaceae are trees growing from 2 to m tall, mostly evergreen, resinous, monoecious, with subopposite or whorled branches, the embryos of Pinaceae have three to 24 cotyledons.
The female cones are large and usually woody, 2—60 cm long, with spirally arranged scales. The male cones are small,0. Analysis of Pinaceae cones reveals how selective pressure has shaped the evolution of variable cone size, variation in cone size in the family has likely resulted from the variation of seed dispersal mechanisms available in their environments over time.
All Pinaceae with seeds weighing less than 90 mg are seemingly adapted for wind dispersal, pines having seeds larger than mg are more likely to have benefited from adaptations that promote animal dispersal, particularly by birds. Pinaceae that persist in areas where tree squirrels are abundant do not seem to have evolved adaptations for bird dispersal, boreal conifers have many adaptions for winter. Classification of the subfamilies and genera of Pinaceae has been subject to debate in the past, Pinaceae ecology, morphology, and history have all been used as the basis for methods of analyses of the family.
An publication divided the family into two subfamiles, using the number and position of resin canals in the primary region of the young taproot as the primary consideration. In a publication, the family was divided into two based on the occurrence and type of long—short shoot dimorphism. A more recent classification divided the subfamilies and genera based on the consideration of features of ovulate cone anatomy among extant, below is an example of how the morphology has been used to classify Pinaceae.
Sieve element plastids of Gymnospermae, their ultrastructure and relation to systematics, D. The dispersal of winged fruits and seeds differing in autorotative behavior, a. Hidrocarburo — In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon, and thus are group 14 hydrides.
Hydrocarbons from which one atom has been removed are functional groups. Aromatic hydrocarbons, alkanes, alkenes, cycloalkanes and alkyne-based compounds are different types of hydrocarbons, the classifications for hydrocarbons, defined by IUPAC nomenclature of organic chemistry are as follows, Saturated hydrocarbons are the simplest of the hydrocarbon species. Saturated hydrocarbons are the basis of petroleum fuels and are found as linear or branched species.
Substitution reaction is their characteristics property, hydrocarbons with the same molecular formula but different structural formulae are called structural isomers. As given in the example of 3-methylhexane and its higher homologues, chiral saturated hydrocarbons constitute the side chains of biomolecules such as chlorophyll and tocopherol. Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms and those with double bond are called alkenes.
Those with one double bond have the formula CnH2n and those containing triple bonds are called alkyne. Hydrocarbons can be gases, liquids, waxes or low melting solids or polymers, in terms of shells, carbon consists of an incomplete outer shell, which comprises 4 electrons, and thus has 4 electrons available for covalent or dative bonding. Some hydrocarbons also are abundant in the solar system, lakes of liquid methane and ethane have been found on Titan, Saturns largest moon, confirmed by the Cassini-Huygens Mission.
Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon compounds, hydrocarbons are a primary energy source for current civilizations. The predominant use of hydrocarbons is as a fuel source. In their solid form, hydrocarbons take the form of asphalt, mixtures of volatile hydrocarbons are now used in preference to the chlorofluorocarbons as a propellant for aerosol sprays, due to chlorofluorocarbons impact on the ozone layer.
Methane and ethane are gaseous at ambient temperatures and cannot be liquefied by pressure alone. Propane is however easily liquefied, and exists in propane bottles mostly as a liquid, butane is so easily liquefied that it provides a safe, volatile fuel for small pocket lighters. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms, Atoms are very small, typical sizes are around picometers. Atoms are small enough that attempting to predict their behavior using classical physics - as if they were billiard balls, through the development of physics, atomic models have incorporated quantum principles to better explain and predict the behavior.
Every atom is composed of a nucleus and one or more bound to the nucleus. The nucleus is made of one or more protons and typically a number of neutrons. Protons and neutrons are called nucleons, more than The protons have an electric charge, the electrons have a negative electric charge.
If the number of protons and electrons are equal, that atom is electrically neutral, if an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion. The electrons of an atom are attracted to the protons in a nucleus by this electromagnetic force. The number of protons in the nucleus defines to what chemical element the atom belongs, for example, the number of neutrons defines the isotope of the element.
The number of influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the changes observed in nature. The idea that matter is made up of units is a very old idea, appearing in many ancient cultures such as Greece.
The word atom was coined by ancient Greek philosophers, however, these ideas were founded in philosophical and theological reasoning rather than evidence and experimentation.
As a result, their views on what look like. They also could not convince everybody, so atomism was but one of a number of competing theories on the nature of matter. It was not until the 19th century that the idea was embraced and refined by scientists, in the early s, John Dalton used the concept of atoms to explain why elements always react in ratios of small whole numbers.
Carbono — Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds, three isotopes occur naturally, 12C and 13C being stable, while 14C is a radioactive isotope, decaying with a half-life of about 5, years.
Carbon is one of the few elements known since antiquity, Carbon is the 15th most abundant element in the Earths crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is the second most abundant element in the body by mass after oxygen. The atoms of carbon can bond together in different ways, termed allotropes of carbon, the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form, for example, graphite is opaque and black while diamond is highly transparent.
Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known, graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials, all carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form.
The largest sources of carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil. For this reason, carbon has often referred to as the king of the elements. The allotropes of carbon graphite, one of the softest known substances, and diamond. It bonds readily with other small atoms including other carbon atoms, Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds.
Carbon also has the highest sublimation point of all elements, although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature. Carbon is the element, with a ground-state electron configuration of 1s22s22p2. Its first four ionisation energies, Carbons covalent radii are normally taken as Carbon compounds form the basis of all life on Earth. It is a member of the group on the periodic table and is a highly reactive nonmetal.
By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide.
Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion.
One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone.
In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it.
Accounts of these and other experiments and ideas were published in in his work Tractatus duo in the tract De respiratione.