Olympiad tasks in chemistry. Chlorophyll References
Chlorophyll is the term used to refer to several closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants. The name comes from the Greek words χλωρός, chloros ("green") and φύλλον, phyllon ("leaf"). Chlorophyll is an extremely important biomolecule, critical to the process of photosynthesis, which allows plants to absorb light energy. Chlorophyll absorbs light most intensely in the blue part of the electromagnetic radiation spectrum, as well as in the red part. On the other hand, chlorophyll does not absorb well the green and near-green parts of the spectrum that it reflects, which is why chlorophyll-containing tissues have a green color. Chlorophyll was first isolated and named by Joseph Bieneme Cavantou and Pierre Joseph Pelletier in 1817.
Chlorophyll and photosynthesis
Chlorophyll is vital for photosynthesis, which allows plants to absorb light energy. Chlorophyll molecules are specifically located in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. In these complexes, chlorophyll performs two main functions. The function of the vast majority of chlorophyll (up to several hundred molecules in a photosystem) is to absorb light and transfer light energy by resonant energy transfer to a specific chlorophyll pair in the reaction center of photosystems. The two currently accepted units of photosystems are photosystem II and photosystem I, which have their own distinct reaction centers called P680 and P700, respectively. These centers are named by the wavelength (in nanometers) of their maximum absorption in the red spectrum. The identity, functionality and spectral properties of chlorophyll in each photosystem are different and are determined by each other and the protein structure surrounding them. Once extracted from the protein in a solvent (such as acetone or methanol), the chlorophyll pigments can be separated into chlorophyll a and b. The function of the chlorophyll reaction center is to absorb light energy and transfer it to other parts of the photosystem. The absorbed photon energy is transferred to the electron in a process called charge separation. Removing an electron from chlorophyll is an oxidation reaction. Chlorophyll donates a high-energy electron to a series of molecular intermediates called the electron transport chain. The charged chlorophyll reaction center (P680+) is then reduced back to the ground state by accepting the electron separated from the water. The electron that reduces P680+ ultimately comes from the oxidation of water to O2 and H+ through several intermediates. During this reaction, photosynthetic organisms such as plants produce O2 gas, which is the source of virtually all O2 in the Earth's atmosphere. Photosystem I usually works in series with photosystem II; thus, P700+ of photosystem I is usually reduced when it accepts an electron, through a variety of intermediates in the thylakoid membrane, with the help of electrons that ultimately come from photosystem II. Electron transfer reactions in thylakoid membranes are complex, and the source of electrons used to reduce P700+ can vary. The electron flow that is generated by the chlorophyll reaction center pigments is used to pump H+ ions across the thylakoid membrane, setting up the chemiosmotic potential, used primarily in the production of ATP (stored chemical energy), or in the reduction of NADP+ to NADPH. NADP is a versatile agent used to reduce CO2 into sugars, as well as in other biosynthetic reactions. RC chlorophyll-protein complexes are capable of directly absorbing light and separating charges without the help of other chlorophyll pigments, but the probability of this at a given light intensity is low. Thus, other chlorophylls of the photosystem and antenna pigment proteins cooperatively absorb and transfer light energy to the reaction center. Besides chlorophyll a, there are other pigments called accessory pigments that take place in these antenna pigment-protein complexes.
Chemical structure
Chlorophyll is a chlorin pigment that is structurally similar to and produced through the same metabolic pathway as other porphyrin pigments such as heme. At the center of the chlorin ring is a magnesium ion. This was discovered in 1906 and was the first time magnesium was found in living tissue. The chlorine ring can have several different side chains, typically including a long phytol chain. There are several different forms that occur in nature, but the most common form in land plants is chlorophyll a. Following initial work done by German chemist Richard Willstätter from 1905 to 1915, Hans Fischer determined the general structure of chlorophyll a in 1940. By 1960, when most of the stereochemistry of chlorophyll a was known, Woodward published a complete synthesis of the molecule. In 1967, the last remaining stereochemical explanation was given by Ian Fleming, and in 1990 Woodward et al published an updated synthesis. Chlorophyll e was announced to be present in cyanobacteria and other oxygenic microorganisms that form stromatolites in 2010. The molecular formula C55H70O6N4Mg and the structure of (2-formyl)-chlorophyll were deduced from NMR, optical and mass spectra.
Chlorophyll content measurement
Light absorption measurements are complicated by the solvent used to extract chlorophyll from the plant material, which affects the values obtained. In diethyl ether, chlorophyll a has approximate absorption maxima of 430 nm and 662 nm, while chlorophyll b has approximate maxima of 453 nm and 642 nm. The absorption peaks of chlorophyll a are 665 nm and 465 nm. Chlorophyll fluoresces at 673 nm (maximum) and 726 nm. The peak molar absorption coefficient of chlorophyll a exceeds 105 M-1 cm-1, and is one of the highest for small molecules of organic compounds. In 90% acetone-water, the peak absorption wavelengths of chlorophyll a are 430 nm and 664 nm; peaks for chlorophyll b – 460 nm and 647 nm; peaks for chlorophyll c1 – 442 nm and 630 nm; peaks for chlorophyll c2 – 444 nm and 630 nm; peaks for chlorophyll d are 401 nm, 455 nm and 696 nm. By measuring the absorption of light in the red and far-red spectra, it is possible to estimate the concentration of chlorophyll in the leaf. Fluorescence emission coefficient can be used to measure chlorophyll content. By exciting chlorophyll a fluorescence at a lower wavelength, the ratio of chlorophyll fluorescence emission at 705 nm +/- 10 nm and 735 nm +/- 10 nm can provide a linear relationship of chlorophyll content compared to chemical tests. The F735/F700 ratio provided an r2 correlation value of 0.96 compared to chemical tests ranging from 41 mg m-2 to 675 mg m-2. Gitelzon also developed a formula to directly read chlorophyll content in mg m-2. The formula provided a reliable method for measuring chlorophyll content from 41 mg m-2 to 675 mg m-2 with an r2 correlation value of 0.95.
Biosynthesis
In plants, chlorophyll can be synthesized from succinyl-CoA and glycine, although the immediate precursor to chlorophyll a and b is protochlorophyllide. In angiosperms, the final step, the conversion of protochlorophyllide to chlorophyll, is light dependent, and such plants are pale when grown in the dark. Non-vascular plants and green algae have an additional enzyme that is independent of light and are able to turn green in the dark. Chlorophyll binds to proteins and can transfer absorbed energy in the right direction. Protochlorophyllide occurs primarily in free form and, under light conditions, acts as a photosensitizer, producing highly toxic free radicals. Therefore, plants require an effective mechanism to regulate the amount of chlorophyll precursor. In angiosperms, this is done at the step of aminolevulinic acid (ALA), one of the intermediates in the biosynthetic pathway. Plants that feed on ALA accumulate high and toxic levels of protochlorophyllide; Mutants with a damaged regulatory system do the same.
Chlorosis
Chlorosis is a condition in which leaves produce insufficient chlorophyll, causing them to turn yellow. Chlorosis can be caused by a nutritional deficiency of iron, called ferric chlorosis, or by a lack of magnesium or nitrogen. Soil pH sometimes plays a role in nutrition-induced chlorosis; Many plants are adapted to grow in soils with certain pH levels and their ability to absorb nutrients from the soil may be affected by this. Chlorosis can also be caused by pathogens, including viruses, bacteria and fungal infections, or by sucking insects.
Additional light absorption of anthocyanins with chlorophyll
Anthocyanins are other plant pigments. The absorption pattern responsible for the red color of anthocyanins may complement the green chlorophyll in photosynthetically active tissues such as young leaves of Quercus coccifera. It may protect the leaves from attack by herbivores that may be attracted to the green color.
Uses of chlorophyll
Culinary use
Chlorophyll is registered as a food additive (colorant), and its number is E140. Chefs use chlorophyll to color various foods and drinks green, such as pasta and absinthe. Chlorophyll is not soluble in water and is first mixed with a small amount of vegetable oil to obtain the desired solution.
Benefit for health
Chlorophyll helps strengthen the blood-forming organs, ensuring the prevention of anemia and an abundance of oxygen in the body. Its antioxidant activity has beneficial effects on various medical conditions such as cancer, insomnia, dental disease, sinusitis, pancreatitis and kidney stones. Chlorophyll promotes normal blood clotting, wound healing, hormonal balance, deodorization and detoxification of the body and promotes digestive health. It has beneficial effects on oxidation and inflammatory diseases such as arthritis and fibromyalgia. It exhibits anti-aging and antimicrobial properties and helps strengthen the body's immune system.
General
Chlorophyll is a food product containing a large amount of nutrients. It is a good source of vitamins such as vitamin A, vitamin C, vitamin E, vitamin K and beta-carotene. It is rich in antioxidants, vital minerals such as magnesium, iron, potassium, calcium and essential fatty acids.
Red blood cells
Chlorophyll helps in repairing and replenishing red blood cells. It works at the molecular and cellular levels and has the ability to regenerate our body. It is rich in living enzymes that help purify the blood and increase the blood's ability to carry more oxygen. It is a blood builder and is also effective against anemia, which is caused by a deficiency of red blood cells in the body.
Cancer
Chlorophyll is effective against cancer, such as human colon cancer, and stimulates the induction of apoptosis. It provides protection against a wide range of carcinogens found in the air, cooked meats and grains. Research has shown that chlorophyll helps in inhibiting the gastrointestinal absorption of harmful toxins, also known as aflatoxins, in the body. Chlorophyll and its derivative chlorophyllin inhibit the metabolism of these procarcinogens, which can damage DNA and also lead to liver cancer and hepatitis. Further studies conducted in this regard demonstrate the chemo-preventive effect of chlorophyll, attributing to it antimutagenic properties. Another study showed the effectiveness of dietary chlorophyll as a phytochemical that reduces tumorigenesis.
Antioxidant
Chlorophyll has strong antioxidant activity, along with significant amounts of essential vitamins. These effective radical scavengers help neutralize harmful molecules and protect against the development of various diseases and damage resulting from oxidative stress caused by free radicals.
Arthritis
The anti-inflammatory properties of chlorophyll are beneficial in treating arthritis. Research has shown that chlorophyll and its derivatives interfere with the growth of inflammation caused by exposure to bacteria. This protective nature of chlorophyll makes it a powerful ingredient for preparing phytosanitary products to treat painful medical conditions such as fibromyalgia and arthritis.
Detoxification
Chlorophyll has cleansing properties that help in detoxifying the body. The abundance of oxygen and healthy blood flow due to chlorophyll in the body helps get rid of harmful impurities and toxins. Chlorophyll complexes with mutagens and has the ability to bind and flush toxic chemicals and heavy metals such as mercury from the body. It promotes liver detoxification and revitalization. It is also effective in reducing the harmful effects of radiation and helps eliminate pesticides and drug deposits from the body.
Anti-aging
Chlorophyll helps fight the effects of aging and support tissue health, due to its richness in antioxidants and the presence of magnesium. It stimulates anti-aging enzymes and promotes healthy, youthful skin. In addition to this, Vitamin K present in it cleanses and rejuvenates the adrenal glands and improves the adrenal gland functions in the body.
Digestive system
Chlorophyll promotes healthy digestion by maintaining intestinal flora and stimulating intestinal motility. It acts as a natural remedy for the gastrointestinal tract and helps in repairing damaged intestinal tissues. Diets that are deficient in green vegetables and contain primarily red meat pose an increased risk of colon disorders. According to research, chlorophyll facilitates colon cleansing by inhibiting cytotoxicity caused by dietary heme and preventing the proliferation of colonocytes. It is effective in relieving constipation and reducing discomfort caused by gas.
Insomnia
Chlorophyll has a calming effect on the nerves and helps in reducing symptoms of insomnia, irritability and general nervous fatigue of the body.
Antimicrobial properties
Chlorophyll has effective antimicrobial properties. Recent research has shown that the healing effect of an alkaline chlorophyll solution in combating a disease called Candida Albicans, an infection caused by an overgrowth of Candida yeast, is already present in small amounts in the human body.
Immunity
Chlorophyll helps strengthen cell walls and the body's overall immune system due to its alkaline nature. Anaerobic bacteria, which contribute to the development of disease, cannot survive in the alkaline environment of chlorophyll. Along with this, chlorophyll is an oxygenator that encourages the body's ability to fight disease and increases energy levels and speeds up the healing process.
Deodorizing properties
Chlorophyll exhibits deodorizing properties. It is effective in combating bad breath and is used in mouthwashes. Poor digestive health is one of the main causes of bad breath. Chlorophyll does double duty by eliminating bad breath and throat while also promoting digestive health by cleansing the colon and blood flow. The deodorizing effect of chlorophyll is also effective on wounds that have an unpleasant odor. It is administered orally to patients suffering from colostomy and metabolic disorders such as trimethylaminuria to reduce fecal and urinary odor.
Wound healing
Research shows that topical application of chlorophyll solutions is effective in treating wounds and burns. It helps reduce local inflammation, strengthens body tissues, helps kill germs and increases cell resistance against infections. It prevents bacterial growth by disinfecting the environment, making it hostile to bacterial growth, and speeds up healing. Chlorophyll is also very effective in treating chronic varicose ulcers.
Acid-base ratio
Consuming foods rich in chlorophyll helps balance the acid-base balance in the body. The magnesium present in it is a powerful alkali. By maintaining appropriate alkalinity and oxygen levels in the body, chlorophyll prevents the development of an environment for the growth of pathogenic microorganisms. Magnesium, present in chlorophyll, also plays an important role in maintaining cardiovascular health, kidney, muscle, liver and brain function.
Strong bones and muscles
Chlorophyll helps form and maintain strong bones. The central atom of the chlorophyll molecule, i.e. Magnesium plays an important role in bone health, along with other essential nutrients such as calcium and vitamin D. It also contributes to muscle tone, contraction and relaxation.
Blood clotting
Chlorophyll contains vitamin K, which is vital for normal blood clotting. It is used in naturopathy to treat nosebleeds and for women suffering from anemia and heavy menstrual bleeding.
Stones in the kidneys
Chlorophyll helps prevent the formation of kidney stones. Vitamin K is present as chlorophyll ester compounds in urine and helps in reducing the growth of calcium oxalate crystals.
Sinusitis
Chlorophyll is effective in treating various respiratory infections and other diseases such as colds, rhinitis and sinusitis.
Hormonal balance
Chlorophyll is useful in maintaining sexual hormonal balance in men and women. Vitamin E present in chlorophyll helps stimulate the production of testosterone in men and estrogen in women.
Pancreatitis
Chlorophyll is administered intravenously in the treatment of chronic pancreatitis. According to a study conducted in this regard, it helps in reducing fever and reduces abdominal pain and discomfort caused by pancreatitis without causing any side effects.
Oral hygiene
Chlorophyll helps in treating dental problems such as pyorrhea. It is used to treat symptoms of oral infection and soothe sore and bleeding gums.
Sources of chlorophyll
It is not very difficult to include chlorophyll in your daily diet, as almost all green plants are rich in chlorophyll a, and many vegetables, which are an integral part of our food, contain chlorophyll a as well as chlorophyll b. Consuming vegetables such as arugula, wheatgrass, leeks, green beans and dark green leafy vegetables such as parsley, cabbage, watercress, Swiss chard and spinach provide natural chlorophyll to the body. Other sources include kale, blue green algae such as chlorella and spirulina. Cooking destroys the chlorophyll and magnesium in food, so raw or steamed vegetables are healthier.
Cautions
Despite clinical use for many years, the toxic effects of natural chlorophyll at normal doses were not known. However, chlorophyll may cause some discoloration of the tongue, urine, or stool when administered orally. Along with this, chlorophyll can also cause a mild burning or itching sensation when applied topically. In rare cases, an overdose of chlorophyll can lead to diarrhea, abdominal cramps and diarrhea. With such symptoms, it is advisable to seek medical help. Pregnant or breastfeeding women should avoid using commercially available chlorophyll or chlorophyll supplements due to a lack of evidence of safety.
Drug interactions
Patients undergoing guaiac occult blood testing should avoid the use of oral chlorophyllin as it may result in a false-positive result.
Summary
Chlorophyll provides the energy of the sun in a concentrated form to our body and is one of the most beneficial nutrients. It increases energy levels and enhances overall well-being. It is also beneficial for obesity, diabetes, gastritis, hemorrhoids, asthma and skin diseases such as eczema. It helps in treating rashes and fighting skin infections. Consuming chlorophyll prophylactically also prevents the adverse effects of surgery and is recommended to be administered before and after surgery. Its magnesium content helps in maintaining blood flow in the body and maintains normal blood pressure levels. Chlorophyll generally improves cellular growth and restores health and vitality in the body.
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List of used literature:
Meskauskiene R; Nater M; Goslings D; Kessler F; op den Camp R; Apel K. (23 October 2001). "FLU: A negative regulator of chlorophyll biosynthesis in Arabidopsis thaliana". Proceedings of the National Academy of Sciences. 98(22):12826–12831. Bibcode:2001PNAS...9812826M. doi:10.1073/pnas.221252798. JSTOR 3056990. PMC 60138free to read. PMID 11606728
Adams, Jad (2004). Hideous absinthe: a history of the devil in a bottle. United Kingdom: I.B.Tauris, 2004. p. 22. ISBN 1860649203.
The main pigment of green plants is the chlorophyll molecule, which is involved in the process of light absorption. Higher plants contain two forms of chlorophyll: chlorophyll a and chlorophyll b. The structure of chlorophyll a (Fig. 40) was established by Wilyptetter and Fischer and confirmed in 1960 by Woodward, who carried out the complete synthesis of chlorophyll a.
The chlorophyll molecule is based on a flat porphyrin ring, in the center of which there is a magnesium atom ion, coordinately connected to the nitrogen atoms of the porphyrin ring.
The flat structure of the porphyrin ring is due to conjugated double and single bonds of electrons between the carbon and nitrogen atoms. These electrons are “delocalized,” that is, they are evenly distributed along the “periphery” of the porphyrin ring (the dotted area in Fig. 40). Changing the state of motion of electrons in the ring requires relatively little energy. Therefore, the light absorption spectrum of the chlorophyll molecule lies in the red region. The electric dipole moment of the transition to the excited state is in the plane of the porphyrin ring.
In addition to the porphyrin ring, the chlorophyll molecule has a long hydrophobic chain - a “tail”, which includes 20 carbon atoms. This side chain is a phytol alcohol residue. Chlorophyll b differs from chlorophyll a in that in the latter the - group is replaced by the - CHO group. Thus, chlorophyll b contains one more oxygen atom and two less hydrogen atoms than chlorophyll a.
The absorption spectra of both forms of chlorophyll are shown in Fig. 41. The maxima of the absorption bands of chlorophyll a lie in the wavelength regions K and 700 nm (red) and K and 440 nm (violet), the maxima of the absorption bands of chlorophyll b are in the wavelength regions of 660 and 460 nm.
The maximum intensity of sunlight reaching the earth's surface occurs in the blue-green and green wavelength regions (450-550 nm). It turns out that it is in these areas that the absorption of light by chlorophyll molecules is minimal.
Chlorophyll a is found in all green plants and algae. Chlorophyll b is absent in many algae. These algae sometimes contain other varieties of chlorophyll: c and d. Photosynthetic bacteria do not produce oxygen and do not contain chlorophyll. They usually contain a special type of chlorophyll - bacteriochlorophyll.
As mentioned above, in addition to chlorophyll molecules, many photosynthetic cells also contain pigment molecules,
Rice. 40. Structural formulas of chlorophyll a and chlorophyll b.
absorbing light in other areas of the spectrum and giving organisms different colors. These molecules expand the spectral region of light used in photosynthesis. In addition, carotenoids protect chlorophyll from irreversible photo-oxidation by oxygen.
The structural formulas of one of the carotenes and phycocyanobilin are shown in Fig. 42. Carotenes have long polyisoprene chains of conjugated double and single bonds. At each end of the molecule there are cyclohexane rings. Phycocyans, which are part of blue-green algae, contain four pyrole rings. They can form complexes with specific proteins.
In Fig. Figure 43 shows a diagram of the first energy levels of the chlorophyll a molecule. In the ground state the molecule has zero spin. All excited states with zero spin are called singlet (S). A molecule can also have excited states with a spin of one (in units of h). They are called triplet (T). Lifetime of the first singlet state. Lifetime of a zero triplet state.
Rice. 41. Light absorption spectra of chlorophyll a (1) and chlorophyll b (2).
Under the influence of light, only transitions to singlet excited states occur in the molecule. If chlorophyll molecules, when absorbing light, go into excited states with energies exceeding the energy of the first excited state, then due to non-radiative processes in 10-12 - 10-13 s they go into the first singlet excited state, giving up excess energy to the solvent.
From the single-state state, a transition occurs over time to the ground state with the emission of light (nm). This phenomenon is called fluorescence. There is also a small probability of a non-radiative transition of a molecule from an excited state to a triplet excited state. Due to the weak interaction of spin with an electromagnetic wave, the lifetime of the triplet state with respect to light emission X 930 nm during the transition to the ground singlet state is relatively long. The long lifetime of the triplet state is due to the unlikely process of changing the spin of the molecule from one to zero.
Solutions containing pigment molecules of only one type (chlorophyll b, chlorophyll a, carotenoids, etc.) at low temperatures have characteristic fluorescence spectra corresponding to quantum transitions of electrons from the lowest singlet excited states to the ground singlet state of the molecule. Along with the main radiation, weak, slowly decaying and longer wavelength radiation is observed, corresponding to transitions from the lowest triplet states of these molecules to the ground singlet state.
Due to the fact that electronic transitions in pigment molecules are accompanied by changes in many low-frequency vibrational states of molecules and the environment, their absorption and luminescence bands have a significant width.
When studying the fluorescence of pigments included in the composition
Rice. 42. Structural formulas of photosynthetic pigments: a - beta-caratine; b - phycocyanobilin.
chloroplasts, only chlorophyll a fluorescence is observed. The shorter wavelength fluorescence of chlorophyll 6 and other pigment molecules is not detected even when the chloroplast is illuminated with light with a wavelength that matches the wavelength of the absorption spectrum of the corresponding pigment.
Thus, the bulk of pigment molecules act as light-harvesting systems (antennas). Pigment molecules in chloroplasts form ensembles of ordered molecules.
The properties of chloroplast fluorescence noted above indicate that in such ensembles there is a relatively rapid (10-11 - 10-12 s) migration of singlet excitation energy along the pigment molecules to the chlorophyll a molecules.
Quantum theory of systems of weakly interacting identical molecules shows that, as a result of the resonant interaction between excited and unexcited molecules, collective currentless excited states arise in the system - excitons, transferring excitation from one place in the system to another. Resonant interaction decreases relatively slowly with increasing distance (as ) and can appear even at distances of the order of 50 A.
When an exciton, moving through a system of pigment molecules, reaches a chlorophyll a molecule, which has a lower excitation level, it transfers it to an excited state,
Rice. 43. Scheme of singlet (S t) and triplet (71,) energy levels of the chlorophyll a molecule.
Straight lines correspond to absorption, wavy arrows - fluorescence; numbers indicate wavelengths in nanometers.
giving excess energy to the thermal reservoir. Such a small loss of energy eliminates the reverse transfer of excitation energy from chlorophyll a molecules to pigment light-harvesting molecules.
The chlorophyll a molecule, having received energy from light-harvesting molecules, releases it in the form of light emission - fluorescence. This phenomenon has been well studied in the study of the luminescence of molecular crystals containing impurity molecules with an excitation energy lower than the excitation energy of the molecules of the main substance, and is called sensitized luminescence.
For some time it was believed that the molecules that receive excitation energy from light-harvesting molecules are special molecules of chlorophyll a. It has now been established (see section 17.2) that this role is played in chloroplasts and chromatophores by special photosynthetic reaction centers, which include several chlorophyll molecules. These molecules in the reaction center form a kind of complex, acting as a single whole with its own spectrum of excited states. Moreover, the energy of the lowest of them is less than the energy of an individual chlorophyll molecule. It has been established that the number of reaction centers in the membrane is significantly less than the number of light-harvesting molecules (1/400).
Photosynthetic reaction centers (exciton traps) are part of photosynthetic systems (PS), in which the light reactions of photosynthesis are carried out. Photosynthetic systems, along with reaction centers that perceive light energy, contain a number of other molecules - enzymes, proteins, lipids, lipoproteins, which are involved in the organization of the photosynthetic system and in its performance of the light part of biochemical reactions. Photosynthetic systems are relatively rigidly embedded in thylakoid membranes.
From the point of view of studying the primary processes of photosynthesis at the molecular level, of particular interest is the study of the organization of pigment layers and the structure of photosynthetic systems, in particular the study of the reaction centers included in their composition.
Chlorophyll A vs B
Plants and algae are living organisms that can create their own food, and animals get their food from these plants. This process of creating food is called photosynthesis and uses chlorophyll. Chlorophyll is a green pigment in plants and algae that is essentially used in photosynthesis. It absorbs light and energy from the blue and red portions of the electromagnetic spectrum, but does not absorb the green portion that gives chlorophyll in plants their green color Light and energy are then transferred to the reaction centers of two photosystems, Photosystem I and Photosystem II. These photosystems have reaction centers, P680 and P700, that absorb and use the energy they receive from other chlorophyll pigments. Photosynthesis uses two types of chlorophyll, chlorophyll a and b, to produce energy. Chlorophyll A Chlorophyll a absorbs energy from blue-violet and orange-red light wavelengths at 675 nm. It reflects green light, which gives chlorophyll its green appearance. It is very important in the energy phase of photosynthesis because chlorophyll a molecules are needed before photosynthesis can continue. This is the primary photosynthetic pigment. This is the reaction center of the antenna array, which consists of basic proteins that bind chlorophyll a to carotenoids. Organisms, particularly oxygen photosynthetic organisms, use chlorophyll a and use various enzymes for biosynthesis. Chlorophyll B Chlorophyll b absorbs energy from green light wavelengths at 640 nm. This is an auxiliary pigment that collects energy and transfers it to chlorophyll a. It also regulates antenna size and is more absorbable than chlorophyll a. Chlorophyll b complements chlorophyll a. Its addition to chlorophyll a increases the absorption spectrum by increasing the range of wavelengths and expanding the spectrum of absorbed light. When there is little light, plants produce more chlorophyll b than chlorophyll a to increase its ability to photosynthesize. This is necessary because chlorophyll a molecules capture a limited wavelength, so accessory pigments such as chlorophyll b are needed to capture a wider range of light. It then passes the trapped light from one pigment to another until it reaches chlorophyll a at the reaction center. Chlorophyll a cannot function effectively without the help of chlorophyll b, and chlorophyll b cannot efficiently produce enough energy on its own. These two types of chlorophylls are therefore very important in the process of photosynthesis. They work best together. Summary 1. Chlorophyll a is the main photosynthetic pigment, and chlorophyll b is an auxiliary pigment that accumulates energy and transfers it to chlorophyll a. 2. Chlorophyll a absorbs energy from blue-violet and orange-red light wavelengths, and chlorophyll b absorbs energy from green light wavelengths. 3. Chlorophyll a absorbs energy at 675 nm, while chlorophyll b absorbs energy at 640 nm. 4. Chlorophyll b is more absorbent, but chlorophyll a is not. 5. Chlorophyll a is the reaction center of the antenna lattice of the main proteins, and chlorophyll b regulates the size of the antenna.
Lecture outline:
4. Chlorophyll biosynthesis
6. Carotenoids
7. Phycobilins
1. Photosynthesis pigments. Chlorophylls
In order for light to have an effect on a plant organism and, in particular, to be used in the process of photosynthesis, it must be absorbed by photoreceptor pigments. Pigments- These are colored substances. Pigments absorb light of a specific wavelength. The unabsorbed parts of the solar spectrum are reflected, which determines the color of the pigments. Thus, the green pigment chlorophyll absorbs red and blue rays, while green rays are mainly reflected. The visible part of the solar spectrum includes wavelengths from 400 to 700 nm. Substances that absorb the entire visible part of the spectrum appear black.
The composition of pigments depends on the systematic position of the group of organisms. Photosynthetic bacteria and algae have a very diverse pigment composition (chlorophylls, bacteriochlorophylls, bacteriorhodopsin, carotenoids, phycobilins). Their set and ratio are specific to different groups and largely depend on the habitat of the organisms. Photosynthetic pigments in higher plants are much less diverse. Pigments concentrated in plastids can be divided into three groups: chlorophylls, carotenoids, phycobilins.
The most important role in the process of photosynthesis is played by green pigments - chlorophylls. French scientists P.Zh. Pelletier and J. Caventou (1818) isolated a green substance from leaves and called it chlorophyll (from the Greek “chloros” - green and “phyllon” - leaf). Currently, about ten chlorophylls are known. They differ in chemical structure, color, and distribution among living organisms. All higher plants contain chlorophylls A And b. Chlorophyll With found in diatoms, chlorophyll d- in red algae. In addition, four bacteriochlorophylls are known (a, b, c And d), contained in the cells of photosynthetic bacteria. The cells of green bacteria contain bacteriochlorophylls With And d, in the cells of purple bacteria - bacteriochlorophylls A And b. The main pigments, without which photosynthesis does not occur, are chlorophylls for green plants and bacteriochlorophylls for bacteria.
For the first time, an accurate idea of the pigments of green leaves of higher plants was obtained thanks to the work of the largest Russian botanist M.S. Colors (1872-1919). He developed a chromatographic method for separating substances and isolated the leaf pigments in their pure form. The chromatographic method for separating substances is based on their different adsorption abilities. This method has been widely used. M.S. The color passed the extract from the leaf through a glass tube filled with powder - chalk or sucrose (chromatographic column). The individual components of the pigment mixture differed in the degree of adsorbability and moved at different speeds, as a result of which they concentrated in different zones of the column. By dividing the column into separate parts (zones) and using the appropriate solvent system, each pigment could be isolated. It turned out that the leaves of higher plants contain chlorophyll A and chlorophyll b, as well as carotenoids (carotene, xanthophyll, etc.). Chlorophylls, like carotenoids, are insoluble in water, but highly soluble in organic solvents. Chlorophylls A And b vary in color: chlorophyll A has a blue-green tint, and chlorophyll b- yellow-green. Chlorophyll content A the leaf contains about three times more chlorophyll b.
2. Chemical properties of chlorophyll
According to the chemical structure, chlorophylls are esters of dicarboxylic organic acid - chlorophyllin and two residues of phytol and methyl alcohols. The empirical formula is C 55 H 72 O 5 N 4 Mg. Chlorophyllin is a nitrogen-containing organometallic compound related to magnesium porphyrins.
In chlorophyll, the hydrogen of the carboxyl groups is replaced by the residues of two alcohols - methyl CH 3 OH and phytol C 20 H 39 OH, therefore chlorophyll is an ester. On Figure 1, A the structural formula of chlorophyll is given A.
Chlorophyll b differs in that it contains two less hydrogen atoms and one more oxygen atom (instead of the CH 3 group, the CHO group (Fig. 1, B) . In this regard, the molecular weight of chlorophyll A - 893 and chlorophyll b- 907. In 1960 R.B. Woodward carried out the total synthesis of chlorophyll.
At the center of the chlorophyll molecule is a magnesium atom, which is connected to four nitrogen atoms of pyrrole groups. The pyrrole groups of chlorophyll have a system of alternating double and single bonds. That's what it is chromophore a group of chlorophyll that determines the absorption of certain rays of the solar spectrum and its color. The diameter of the porphyrin core is 10 nm, and the length of the phytol residue is 2 nm.
Figure 1 – Chlorophylls A And b
The distance between the nitrogen atoms of the pyrrole groups in the chlorophyll nucleus is 0.25 nm. Interestingly, the diameter of a magnesium atom is 0.24 nm. Thus, magnesium almost completely fills the space between the nitrogen atoms of pyrrole groups. This gives the core of the chlorophyll molecule additional strength. Also K.A. Timiryazev drew attention to the similarity of the chemical structure of two important pigments: green - leaf chlorophyll and red - blood hemin. Indeed, if chlorophyll belongs to magnesium porphyrins, then hemin belongs to iron porphyrins. This similarity is not accidental and serves as another proof of the unity of the entire organic world.
One of the specific features of the structure of chlorophyll is the presence in its molecule, in addition to four heterocycles, of another cyclic group of five carbon atoms - cyclopentanone. The cyclopentane ring contains a keto group, which is highly reactive. There is evidence that as a result of the enolization process, water is added to the chlorophyll molecule at the site of this keto group.
The chlorophyll molecule is polar, its porphyrin core has hydrophilic properties, and its phytol end has hydrophobic properties. This property of the chlorophyll molecule determines its specific location in the membranes of chloroplasts. The porphyrin part of the molecule is associated with protein, and the phytol chain is immersed in the lipid layer.
Chlorophyll extracted from the leaf reacts easily with both acids and alkalis. When interacting with alkalis, saponification of chlorophyll occurs, resulting in the formation of two alcohols and an alkaline salt of chlorophyllin acid. In an intact living leaf, phytol can be cleaved from chlorophyll under the influence of the enzyme chlorophyllase. When interacting with a weak acid, the extracted chlorophyll loses its green color and the compound pheophytin is formed, in which the magnesium atom in the center of the molecule is replaced by two hydrogen atoms.
Chlorophyll in a living intact cell has the ability to undergo reversible photooxidation and photoreduction. The ability for redox reactions is associated with the presence in the chlorophyll molecule of conjugated double bonds with mobile
π-electrons and nitrogen atoms with lone electrons. The nitrogen of the pyrrole cores can be oxidized (donate an electron) or reduced (gain an electron).
Studies have shown that the properties of chlorophyll found in the leaf and extracted from the leaf are different, since in the leaf it is complexed with protein. This is proven by the following data:
The absorption spectrum of chlorophyll present in the leaf is different compared to extracted chlorophyll.
Chlorophyll cannot be extracted with absolute alcohol from dry leaves. Extraction is successful only if the leaves are moistened or water is added to the alcohol, which destroys the bond between chlorophyll and protein.
Chlorophyll isolated from a leaf is easily destroyed under the influence of a wide variety of influences (increased acidity, oxygen and even light).
Meanwhile, chlorophyll in the leaf is quite resistant to all of the above factors. It should be noted that although the prominent Russian scientist V.N. Lyubimenko proposed calling this complex chloroglobin, by analogy with hemoglobin, the connection between chlorophyll and protein is of a different nature than between hemin and protein. Hemoglobin is characterized by a constant ratio - for 1 protein molecule there are 4 hemin molecules. Meanwhile, the ratio between chlorophyll and protein is different and undergoes changes depending on the type of plants, the phase of their development, and environmental conditions (from 3 to 10 molecules of chlorophyll per 1 molecule of protein). The connection between protein molecules and chlorophyll is carried out through unstable complexes formed by the interaction of the acidic groups of protein molecules and the nitrogen of pyrrole rings. The higher the content of dicarboxylic amino acids in the protein, the better their complexation with chlorophyll (T.N. Godney). Proteins associated with chlorophyll are characterized by a low isoelectric point (3.7-4.9). The molecular weight of these proteins is about 68 kDa. At the same time, chlorophyll can also interact with membrane lipids.
An important property of molecules chlorophyll is their ability to interact with each other. The transition from the monomeric to the aggregated form arose as a result of the interaction of two or more molecules when they were close to each other. During the formation of chlorophyll, its state in a living cell naturally changes. At the same time, its aggregation occurs (A.A. Krasnovsky). It has now been shown that chlorophyll in plastid membranes is in the form of pigment-lipoprotein complexes with varying degrees of aggregation.
3. Physical properties of chlorophyll
As already noted, chlorophyll is capable of selective absorption of light. The absorption spectrum of a given compound is determined by its ability to absorb light of a certain wavelength (certain color). In order to obtain the absorption spectrum of K.A. Timiryazev passed a beam of light through a chlorophyll solution. Some of the rays were absorbed by chlorophyll, and upon subsequent transmission through a prism, black bands were discovered in the spectrum. It has been shown that chlorophyll at the same concentration as in the leaf has two main absorption lines in red and blue-violet rays . At the same time, chlorophyll A in solution has an absorption maximum of 429 and 660 nm, while chlorophyll b- 453 and 642 nm. However, it must be taken into account that the absorption spectra of chlorophyll in a leaf vary depending on its state, the degree of aggregation, and adsorption on certain proteins. It has now been shown that there are forms of chlorophyll that absorb light at wavelengths of 700, 710 and even 720 nm. These forms of chlorophyll, which absorb long-wavelength light, are especially important in the process of photosynthesis.
Chlorophyll has the ability to fluoresce. Fluorescence is the glow of bodies, excited by illumination and lasting a very short period of time (10 8 -10 9 s). The light emitted during fluorescence always has a longer wavelength compared to that absorbed. This is due to the fact that part of the absorbed energy is released in the form of heat. Chlorophyll has red fluorescence.
4. Chlorophyll biosynthesis
The synthesis of chlorophyll occurs in two phases: dark - to protochlorophyllide and light - the formation of chlorophyllide from protochlorophyllide (Fig. 2). The synthesis begins with the conversion of glutamic acid to δ-aminolevulinic acid. 2 molecules of δ-aminolevulinic acid condense into porphobilinogen. Next, 4 molecules of porphobilinogen are converted into protoporphyrin IX. After this, magnesium is incorporated into the ring and protochlorophyllide is obtained. In light and in the presence of NADH, chlorophyllide is formed: protochlorophyllide + 2H + + hv →chlorophyllide
Figure 2 - Scheme of chlorophyll biosynthesis
Protons attach to the fourth pyrrole ring in the pigment molecule. At the last stage, the interaction of chlorophyllide with phytol alcohol occurs: chlorophyllide + phytol → chlorophyll.
Since the synthesis of chlorophyll is a multistage process, various enzymes are involved in it, apparently making up a multienzyme complex. It is interesting to note that the formation of many of these enzyme proteins is accelerated by light. Light indirectly accelerates the formation of chlorophyll precursors. One of the most important enzymes is the enzyme that catalyzes the synthesis of δ-aminolevulinic acid (aminolevulinate synthase). It is important to note that the activity of this enzyme also increases in light.
5. Conditions for the formation of chlorophyll
Studies of the influence of light on the accumulation of chlorophyll in etiolated seedlings made it possible to establish that chlorophyll appears first in the greening process A. Spectrographic analysis shows that the process of chlorophyll formation occurs very quickly. Yes, already after
1 min after the start of illumination, the pigment isolated from etiolated seedlings has an absorption spectrum coinciding with the absorption spectrum of chlorophyll A. According to A.A. Shlyka, chlorophyll b formed from chlorophyll A.
When studying the influence of light quality on the formation of chlorophyll, in most cases the positive role of red light was revealed. Light intensity is of great importance. The existence of a lower limit of illumination for the formation of chlorophyll was shown in experiments by V.N. Lyubimenko for barley and oat sprouts. It turned out that illumination with a 10 W electric lamp at a distance of 400 cm was the limit below which the formation of chlorophyll stopped. There is also an upper limit of illumination, above which the formation of chlorophyll is inhibited.
Seedlings grown in the absence of light are called etiolated. Such seedlings are characterized by a changed shape (elongated stems, undeveloped leaves) and a weak yellow color (they have no chlorophyll). As mentioned above, the formation of chlorophyll in the final stages requires light.
Since the time of J. Sachs (1864), it has been known that in some cases chlorophyll is formed in the absence of light. The ability to form chlorophyll in the dark is characteristic of organisms at the lower stage of the evolutionary process. Thus, under favorable nutritional conditions, some bacteria can synthesize bacteriochlorophyll in the dark. Cyanobacteria, when provided with sufficient organic matter, grow and form pigments in the dark. The ability to form chlorophyll in the dark has also been found in such highly organized algae as Characeae. Deciduous and liver mosses retain the ability to form chlorophyll in the dark. In almost all types of conifers, when seeds germinate in the dark, the cotyledons turn green. This ability is more developed in shade-tolerant species of coniferous trees. As the seedlings grow in the dark, the resulting chlorophyll is destroyed, and on the 35-40th day the seedlings die in the absence of light. It is interesting to note that conifer seedlings grown from isolated embryos in the dark do not form chlorophyll. However, the presence of a small piece of uncrushed endosperm is sufficient for the seedlings to begin to turn green. Greening occurs even if the embryo comes into contact with the endosperm of another species of coniferous tree. In this case, a direct correlation is observed between the value of the redox potential of the endosperm and the ability of seedlings to turn green in the dark.
It can be concluded that, in evolutionary terms, chlorophyll was originally formed as a by-product of dark metabolism. However, later in the light, plants with chlorophyll received a greater advantage due to the ability to use the energy of sunlight, and this feature was consolidated by natural selection.
The formation of chlorophyll depends on temperature. The optimal temperature for chlorophyll accumulation is 26-30°C. Only the formation of chlorophyll precursors (dark phase) depends on temperature. In the presence of already formed chlorophyll precursors, the greening process (light phase) proceeds at the same speed, regardless of temperature.
The rate of chlorophyll formation is influenced by water content. Severe dehydration of seedlings leads to a complete cessation of chlorophyll formation. The formation of protochlorophyllide is especially sensitive to dehydration.
Also V.I. Palladium drew attention to the need for carbohydrates for the greening process to occur. This is precisely why the greening of etiolated seedlings in the light depends on their age. After 7-9 days of age, the ability to form chlorophyll in such seedlings drops sharply. When sprayed with sucrose, the seedlings begin to turn intensely green again.
Mineral nutrition conditions are of utmost importance for the formation of chlorophyll. First of all, you need a sufficient amount of iron. With a lack of iron, the leaves of even adult plants lose color. This phenomenon is called chlorosis. Iron is an important catalyst for the formation of chlorophyll. It is necessary at the stage of synthesis of δ-aminolevulinic acid, as well as the synthesis of protoporphyrin. Of great importance for ensuring the synthesis of chlorophyll is the normal supply of plants with nitrogen and magnesium, since both of these elements are part of chlorophyll. With a lack of copper, chlorophyll is easily destroyed. This is apparently due to the fact that copper promotes the formation of stable complexes between chlorophyll and the corresponding proteins.
A study of the process of chlorophyll accumulation in plants during the growing season showed that the maximum chlorophyll content is confined to the beginning of flowering. It is even believed that increased chlorophyll production can be used as an indicator indicating that plants are ready to flower. Chlorophyll synthesis depends on the activity of the root system. Thus, during grafting, the chlorophyll content in the scion leaves depends on the properties of the root system of the rootstock. It is possible that the influence of the root system is due to the fact that hormones (cytokinins) are formed there. In dioecious plants, female leaves are characterized by a high chlorophyll content.
6. Carotenoids
Along with green pigments, chloroplasts and chromatophores contain pigments belonging to the group of carotenoids. Carotenoids are yellow and orange pigments of an aliphatic structure, derivatives of isoprene. Carotenoids are found in all higher plants and many microorganisms. These are the most common pigments with a variety of functions. Carotenoids containing oxygen are called xanthophylls. The main representatives of carotenoids in higher plants are two pigments -
β- carotene(orange) C 40 H 56 and xanthophyll(yellow) C 40 H 56 O 2. Carotene consists of 8 isoprene residues (Fig. 3).
Figure 3 – Structure of β-carotene
When the carbon chain is broken in half and an alcohol group is formed at the end, carotene is converted into 2 molecules of vitamin A. Noteworthy is the similarity in the structure of phytol, an alcohol that is part of chlorophyll, and the carbon chain connecting the ionone rings of carotene. It is assumed that phytol arises as a product of hydrogenation of this part of the carotenoid molecule. The absorption of light by carotenoids, their color, as well as the ability to undergo redox reactions are due to the presence of conjugated double bonds, β-carotene has two absorption maxima, corresponding to wavelengths of 482 and 452 nm. Unlike chlorophylls, carotenoids do not absorb red rays and do not fluoresce. Like chlorophyll, carotenoids in chloroplasts and chromatophores are found in the form of water-insoluble complexes with proteins.
The very fact that carotenoids are always present in chloroplasts suggests that they take part in the process of photosynthesis. However, not a single case has been observed where this process occurs in the absence of chlorophyll. It has now been established that carotenoids, absorbing certain parts of the solar spectrum, transfer the energy of these rays to chlorophyll molecules. Thus, they contribute to the use of rays that are not absorbed by chlorophyll.
The physiological role of carotenoids is not limited to their participation in the transfer of energy to chlorophyll molecules. According to a Russian researcher
DI. Sapozhnikov, in the light the interconversion of xanthophylls occurs (violaxanthin turns into zeaxanthin), which is accompanied by the release of oxygen. The action spectrum of this reaction coincides with the absorption spectrum of chlorophyll, which made it possible to suggest its participation in the process of water decomposition and oxygen release during photosynthesis.
There is evidence that carotenoids perform a protective function, protecting various organic substances, primarily chlorophyll molecules, from destruction in light during the process of photo-oxidation. Experiments conducted on corn and sunflower mutants showed that they contain protochlorophyllide (a dark precursor of chlorophyll), which turns into chlorophyll in light A, but is destroyed. The latter is due to the lack of the ability of the studied mutants to form carotenoids.
A number of researchers indicate that carotenoids play a role in the sexual process in plants. It is known that during the flowering period of higher plants, the content of carotenoids in leaves decreases. At the same time, it grows noticeably in the anthers, as well as in the petals of flowers. According to P. M. Zhukovsky, microsporogenesis is closely related to the metabolism of carotenoids. Immature pollen grains are white in color, while ripe pollen is yellow-orange. A differentiated distribution of pigments is observed in the germ cells of algae. Male gametes are yellow in color and contain carotenoids. Female gametes contain chlorophyll. It is believed that it is carotene that determines sperm motility. According to V. Mevius, mother cells of the Chlamydomonas algae form sex cells (gametes) initially without flagella; during this period they cannot yet move in water. Flagella are formed only after the gametes are illuminated by long-wave rays, which are captured by a special carotenoid - crocetin.
Formation of carotenoids. The synthesis of carotenoids does not require light. During the formation of leaves, carotenoids are formed and accumulated in plastids even during the period when the leaf primordium is protected in the bud from the action of light. At the beginning of illumination, the formation of chlorophyll in etiolated seedlings is accompanied by a temporary drop in the content of carotenoids. However, then the content of carotenoids is restored and even increases with increasing light intensity. It has been established that there is a direct correlative relationship between the content of protein and carotenoids. The loss of protein and carotenoids in cut leaves occurs in parallel. The formation of carotenoids depends on the source of nitrogen nutrition. More favorable results on the accumulation of carotenoids were obtained when plants were grown on a nitrate background compared to ammonia. Lack of sulfur sharply reduces the content of carotenoids. The Ca/Mg ratio in the nutrient medium is of great importance. A relative increase in calcium content leads to increased accumulation of carotenoids compared to chlorophyll. An increase in magnesium content has the opposite effect.
7. Phycobilins
Phycobilins are red and blue pigments found in cyanobacteria and some algae. Research has shown that red algae and cyanobacteria along with chlorophyll A contain phycobilins. The chemical structure of phycobilins is based on four pyrrole groups. Unlike chlorophyll, phycobilins have pyrrole groups arranged in an open chain (Fig. 4) . Phycobilins are represented by pigments: phycocyanin, phycoerythrin And allophycocyanin. Phycoerythrin is an oxidized phycocyanin. Red algae mainly contain phycoerythrin, while cyanobacteria contain phycocyanin. Phycobilins form strong compounds with proteins (phycobilin proteins). The connection between phycobilins and proteins is destroyed only by acid. It is assumed that the carboxyl groups of the pigment bind to the amino groups of the protein. It should be noted that, unlike chlorophylls and carotenoids located in membranes, phycobilins are concentrated in special granules (phycobilisomes), closely associated with thylakoid membranes.
Figure 4 – Chromophore group of phycoerythrins
Phycobilins absorb rays in the green and yellow parts of the solar spectrum. This is the part of the spectrum that lies between the two main absorption lines of chlorophyll. Phycoerythrin absorbs rays with a wavelength of 495-565 nm, and phycocyanin - 550-615 nm. A comparison of the absorption spectra of phycobilins with the spectral composition of light in which photosynthesis occurs in cyanobacteria and red algae shows that they are very close. This suggests that phycobilins absorb light energy and, like carotenoids, transfer it to the chlorophyll molecule, after which it is used in the process of photosynthesis.
The presence of phycobilins in algae is an example of the adaptation of organisms in the process of evolution to the use of areas of the solar spectrum that penetrate through the thickness of sea water (chromatic adaptation). As is known, red rays, corresponding to the main absorption line of chlorophyll, are absorbed when passing through the water column. Green rays penetrate most deeply and are absorbed not by chlorophyll, but by phycobilins.
PHOTOSYNTHESIS (12 hours)
This is chlorophyll. With its help, vegetation acquires the appropriate color. Even at school, children are taught that this substance plays an important role in the process of photosynthesis. Thus, plants cannot exist without it.
But recently it is believed that this pigment can be used for human health. There is information that is sold in pharmacies; purchasing it is not difficult. It is believed that it can help in the treatment of many diseases. But does this substance actually have healing properties?
It has already been said that chlorophyll is the green pigment of a plant, giving it its corresponding color. This is an important element in the life of vegetation, required for photosynthesis. Chlorophyll has a special chemical composition: a magnesium atom is surrounded by atoms of nitrogen, hydrogen, carbon and oxygen.
Almost a hundred years ago, Hans Fischer made an amazing discovery. He noticed that the chemical structures of chlorophyll and hemoglobin were similar. The difference is that instead of magnesium, hemoglobin contains iron. Because of this, the pigment chlorophyll began to be called the blood of plants. Many scientists became interested in this substance and began to study it. Some people wanted to use it in medicine.
Uses of chlorophyll
The green pigment of the plant is today used as a food additive. It is better known as the E-140. With its help, they replace the dyes that are used for chlorophyll. A derivative of chlorophyll is trisodium salt. It is used in the food industry as a dye, called E-141.
Scientists could not realize that the structure of hemoglobin is so similar to chlorophyll. Because of this, it is used not only for dietary supplements. Today, green pigment extract is produced. It is called liquid chlorophyll and is used in medicine as a healing agent. But is it really useful?
Promises of manufacturers regarding liquid chlorophyll
Today, liquid chlorophyll is attracting interest. The plant contains a green pigment that is used for this dietary supplement. The product has attracted people who want to improve their health. The manufacturer who produces it believes that the drug has a beneficial effect on the body, since the structure of the pigment is very similar to hemoglobin.
Buyers are told that liquid chlorophyll has the following properties:
- Removes waste and toxins from the body.
- Regulates the level of hormones that are in the blood.
- With it, the acid-base balance will always be normal.
- The blood is saturated with minerals, nutrients, and vitamins.
- Tissue regeneration occurs faster.
- Immunity improves.
- It can help in some gynecological pathologies.
Experts' opinion
This dietary supplement is presented as an origin that is capable of providing extraordinary healing effects. With its help, you can treat diseases, as well as engage in prevention. But what do experts think about this?
Doctors' opinions were divided:
- Opponents suggest that using liquid chlorophyll is pointless due to the fact that the substance is not able to be fully absorbed in the human body. They also refute theories about healing properties.
- But there are experts who confirm some of the medicinal properties of the drug. They noticed that it really removes toxins and strengthens the immune and cardiovascular systems.
There is no clear opinion. Because of this, each person decides for himself whether he needs this remedy. But, besides this, the green pigment of the plant is needed to purify the air, which is important for human life.
Photosynthesis
One thing is certain: chlorophyll can help saturate the air with oxygen. Photosynthesis is a complex process that involves plants and solar energy. A chemical reaction occurs through which oxygen appears from carbon dioxide. Only this process of life activity of everything on the planet uses the energy of the sun.
Photoautotrophs capture sunlight. This process occurs in plants, some algae and unicellular organisms. Despite the fact that photosynthesis is carried out by lower life entities, half of the work falls on plants.
Terrestrial representatives of vegetation receive water through their roots, which is necessary for this process. There are small holes on the surface of the leaves through which carbon dioxide enters. In the process of all this, oxygen is released. Without chlorophyll, this process is impossible, since it is this green pigment of the plant that absorbs solar energy.
Although there is also non-chlorophyll photosynthesis. It has been seen in salt-loving bacteria that harbor a light-sensitive violet pigment. The latter is capable of absorbing light. But this is an isolated case. Chlorophyll is mainly involved.
Properties of chlorophyll discovered by science
The green pigment has begun to be closely studied in science. Liquid chlorophyll has been proven to promote cell regeneration. But it was still not possible to make a powerful antibiotic, so tablets were preferred.
But research in dentistry has made great progress. Having become interested in the healing properties of chlorophyll, they studied it and noticed a positive effect on the oral cavity. Robert Nahr invented a program that could help fight tooth decay. A toothpaste was released that contained chlorophyll. As you know, this green pigment is actively involved in photosynthesis, through which oxygen is produced. And this is a powerful agent that eliminates bacteria, including those that cause caries. Because of this, the paste has earned recognition, as it showed excellent results.
There were also positive studies that revealed that the pigment fights pancreatitis if taken orally.
So, chlorophyll plays an important role in the life of not only plants, but also all people. With its help, photosynthesis occurs and the oxygen needed by humans is released. Also, liquid chlorophyll began to be used in medicine. Many studies have shown good results.
