In organic chemistry, an alkane, or paraffin, is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula CnH2n+2. The alkanes range in complexity from the simplest case of methane, where n = 1, to arbitrarily large and complex molecules, like pentacontane or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an isomer of tetradecane.
Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH3(CH2)6CH3. Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in the octane rating scale.
Heptane or n-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and iso-octane which is expressed as the percentage of iso-octane in heptane, and is listed on pumps for gasoline (petrol) dispensed globally.
Decane is an alkane hydrocarbon with the chemical formula C10H22. Although 75 structural isomers are possible for decane, the term usually refers to the normal-decane ("n-decane"), with the formula CH3(CH2)8CH3. All isomers, however, exhibit similar properties and little attention is paid to the composition. These isomers are flammable liquids. Decane is present in small quantities (less than 1%) in gasoline (petrol) and kerosene. Like other alkanes, it is a nonpolar solvent, and does not dissolve in water, and is readily combustible. Although it is a component of fuels, it is of little importance as a chemical feedstock, unlike a handful of other alkanes.
Pentane is an organic compound with the formula C5H12—that is, an alkane with five carbon atoms. The term may refer to any of three structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, pentane means exclusively the n-pentane isomer, in which case pentanes refers to a mixture of them; the other two are called isopentane (methylbutane) and neopentane (dimethylpropane). Cyclopentane is not an isomer of pentane because it has only 10 hydrogen atoms where pentane has 12.
In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At its simplest, it's a useful way of converting alkanes, which are relatively inert and thus low-valued, to olefins, which are reactive and thus more valuable. Alkenes are precursors to aldehydes, alcohols, polymers, and aromatics. As a problematic reaction, the fouling and inactivation of many catalysts arises via coking, which is the dehydrogenative polymerization of organic substrates.
Herbivores are dependent on plants for food, and have coevolved mechanisms to obtain this food despite the evolution of a diverse arsenal of plant defenses against herbivory. Herbivore adaptations to plant defense have been likened to "offensive traits" and consist of those traits that allow for increased feeding and use of a host. Plants, on the other hand, protect their resources for use in growth and reproduction, by limiting the ability of herbivores to eat them. Relationships between herbivores and their host plants often results in reciprocal evolutionary change. When a herbivore eats a plant it selects for plants that can mount a defensive response, whether the response is incorporated biochemically or physically, or induced as a counterattack. In cases where this relationship demonstrates "specificity", and "reciprocity", the species are thought to have coevolved. The escape and radiation mechanisms for coevolution, presents the idea that adaptations in herbivores and their host plants, has been the driving force behind speciation. The coevolution that occurs between plants and herbivores that ultimately results in the speciation of both can be further explained by the Red Queen hypothesis. This hypothesis states that competitive success and failure evolve back and forth through organizational learning. The act of an organism facing competition with another organism ultimately leads to an increase in the organism's performance due to selection. This increase in competitive success then forces the competing organism to increase its performance through selection as well, thus creating an "arms race" between the two species. Herbivores evolve due to plant defenses because plants must increase their competitive performance first due to herbivore competitive success.
The furanocoumarins, or furocoumarins, are a class of organic chemical compounds produced by a variety of plants. Most of the plant species found to contain furanocoumarins belong to a handful of plant families. The families Apiaceae and Rutaceae include the largest numbers of plant species that contain furanocoumarins. The families Moraceae and Fabaceae include a few widely distributed plant species that contain furanocoumarins.
Raspberry ketone is a natural phenolic compound that is the primary aroma compound of red raspberries.
The harlequin cabbage bug, also known as calico bug, fire bug or harlequin bug, is a black stinkbug of the family Pentatomidae, brilliantly marked with red, orange, yellow and white markings. It is a major pest of cabbage and related crops in the Brassicaceae, as well as the ornamental flower cleome throughout tropical and North America, especially the warmer parts of the United States. Nymphs are active during the summer and in the tropics the bug can achieve three to six generations a year. In the northern range there is only one generation annually and the insects overwinter as adults in crop residues or field edges. Organic control involves hand-picking the insects off the plants and being especially careful to remove and destroy all the eggs, which are black-and-white striped, laid in clutches of twelve.
Phlorotannins are a type of tannins found in brown algae such as kelps and rockweeds or sargassacean species, and in a lower amount also in some red algae. Contrary to hydrolysable or condensed tannins, these compounds are oligomers of phloroglucinol (polyphloroglucinols). As they are called tannins, they have the ability to precipitate proteins. It has been noticed that some phlorotannins have the ability to oxidize and form covalent bonds with some proteins. In contrast, under similar experimental conditions three types of terrestrial tannins apparently did not form covalent complexes with proteins.
Formica obscuripes, the western thatching ant, is a species of ant in the family Formicidae. It is native to North America. It produces large mounds covered by small pieces of plant material. The number of adult workers per colony may be as high as 40,000. F. obscuripes feeds upon a number of insect species, consumes nectar from homopterous insects they tend, and occasionally eats plant tissue.
Bisabolenes are a group of closely related natural chemical compounds which are classified as sesquiterpenes. Bisabolenes are produced from farnesyl pyrophosphate (FPP) and are present in the essential oils of bisabol, and of a wide variety of other plants including cubeb, lemon, and oregano. Various derivates also function as pheromones in different insects, such as stink bugs and fruit flies. Bisabolenes are produced by several fungi, though their biological role in that group of organisms remains unclear.
Calliphara nobilis is a species of jewel bug found in Asia. Like all species of jewel bugs, it is phytophagous, feeding on the leaves, fruit and seeds of its host plants. This insect is notable for its multiple defense mechanisms: it is highly mobile and swarms disperse with a loud buzz when disturbed; it is aposematically colored, which serves as a warning to any would-be predators that it is unpalatable; and it possesses a robust chemical defense mechanism: it can secrete an irritating and toxic fluid from a pair of metathoracic scent glands when threatened.
Chemical defense is a strategy employed by many organisms to avoid consumption by producing toxic or repellent metabolites or chemical warnings which incite defensive behavioral changes. The production of defensive chemicals occurs in plants, fungi, and bacteria, as well as invertebrate and vertebrate animals. The class of chemicals produced by organisms that are considered defensive may be considered in a strict sense to only apply to those aiding an organism in escaping herbivory or predation. However, the distinction between types of chemical interaction is subjective and defensive chemicals may also be considered to protect against reduced fitness by pests, parasites, and competitors. Repellent rather than toxic metabolites are allomones, a sub category signaling metabolites known as semiochemicals. Many chemicals used for defensive purposes are secondary metabolites derived from primary metabolites which serve a physiological purpose in the organism. Secondary metabolites produced by plants are consumed and sequestered by a variety of arthropods and, in turn, toxins found in some amphibians, snakes, and even birds can be traced back to arthropod prey. There are a variety of special cases for considering mammalian antipredatory adaptations as chemical defenses as well.
Insects have a wide variety of predators, including birds, reptiles, amphibians, mammals, carnivorous plants, and other arthropods. The great majority (80–99.99%) of individuals born do not survive to reproductive age, with perhaps 50% of this mortality rate attributed to predation. In order to deal with this ongoing escapist battle, insects have evolved a wide range of defense mechanisms. The only restraint on these adaptations is that their cost, in terms of time and energy, does not exceed the benefit that they provide to the organism. The further that a feature tips the balance towards beneficial, the more likely that selection will act upon the trait, passing it down to further generations. The opposite also holds true; defenses that are too costly will have a little chance of being passed down. Examples of defenses that have withstood the test of time include hiding, escape by flight or running, and firmly holding ground to fight as well as producing chemicals and social structures that help prevent predation.
Tessaratomidae is a family of true bugs. It contains about 240 species of large bugs divided into 3 subfamilies and 56 genera.
Cosmopepla lintneriana, the twice-stabbed stink bug, is a species of insect in the family Pentatomidae. Cosmopepla lintneriana was first described in 1798 by Johan Christian Fabricius as Cimex carnifex, and then again in 1865 by Thomas Say as Cosmopepla bimaculata. Cosmopepla lintneriana is hosted by a variety of plants, including milk thistle, echinacea, asparagus, oats, mint and goldenrod, and is widespread throughout North America, from Canada to Mexico. Adult C. lintneriana are black with a red, orange, or yellow band across the pronotum and a short red stripe along the midline, and two red spots at the apex of the scutellum. Nymph coloration ranges from red to white with black markings that change as they grow.
Coridius janus, sometimes known as the red pumpkin bug, is a species of bug in the family Dinidoridae. It feeds by sucking on the sap on soft parts of plants especially in the cucurbit family and causes damage to crops.
Hydrocarbonoclastic bacteria are a heterogeneous group of prokaryotes which can degrade and utilize hydrocarbon compounds as source of carbon and energy. Despite being present in most of environments around the world, several of these specialized bacteria live in the sea and have been isolated from polluted seawater.
