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What Is Chitin In Biology

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Regulation Of Chitin Degradation

Carbohydrates: Chitin | A-level Biology | OCR, AQA, Edexcel

Due to the vital role of chitin in insect development, its degradation must be as tightly regulated as its synthesis. By monitoring transcripts or enzyme activities, it has been shown that the expression or activity of integumental chitinases is restricted to periods of molt and pupation whereas that of gut chitinases is induced by feeding . Interestingly, chitinase expression in the molting fluid is delayed compared with –N-acetylglucosaminidase expression. In epidermal cells, 20-hydroxyecdysone stimulates the secretion of the molting fluid containing chitinolytic enzymes and proteases, indicating that this hormone may also be involved in regulating enzyme expression and activity.

In the course of the molting process, the ecdysteroid titer increases continuously and reaches its maximum shortly before apolysis. Juvenile hormone allows larval molting in response to ecdysteroids but prevents the switching of gene expression necessary for metamorphosis. Therefore,the delayed chitinase expression may be caused by differential sensing of hormone titers during molting. Both secretion and activation of chitinolytic enzymes are clearly controlled by ecdysteroids. Concordantly, Kimura showed some 30 years ago that the activity of molting fluid enzymes can be stimulated by ecdysteroid injections.

Production Of Chitin Sheets

Chitin sheets are excellent for use in biomedical devices due to their biodegradability and lack of toxicity. These sheets can be prepared by simple procedures. A solution of -chitin, in saturated calcium chloride dihydratemethanol solvent system, is dropped into excess of distilled water with gentle mixing to desolubilize the -chitin the obtained chitin hydrogel is decanted several times with distilled water and filtered. -Chitin sheets are obtained after the evaporation of water.

Due to the loose crystalline structure of -chitin, it can be highly swollen in water by vigorous mixing using a suitable blender and forms a hydrogel. A suspension will be formed by the addition of excess water to the -chitin hydrogel which is then filtered to form the -chitin sheets.

ROY L. WHISTLER, in, 1993

Chitin Structure And Complexes

Chitin is mainly composed of N-acetyl-d-glucosamine residues, which are attached by –glycosidic linkage . Important functional groups of chitin are listed in Table 1. Chitin is recognized as widely distributed in exoskeleton of invertebrates and cell wall of fungi. Chitin and cellulose are structurally analogous, where in the former the hydroxyl group of glucose moiety is replaced by the acetamide group. However, degree of acetylation in the polysaccharide molecule depends on the source and chitin isolation process. At least, one out of six GlcNAc molecules remains deacetylated in native chitin . It is observed that length of the yeast chitin is only with 100 GlcNAc residues, whereas the crab chitin contains 50008000 GlcNAc residues. Chitin polymer is labile to alkali. It was observed that the length of the chitin chain was decreased upon hot alkali treatment during the deproteinization step of chitin isolation . Each polymeric chitin chain is associated with neighboring chain by hydrogen bond, where amino group of one molecule makes bond with carbonyl group of the adjacent one.

Fig. 1. Linear structure of chitin.

Table 1. List of Functional Groups Inferred from FTIR

Functional Group
NH stretching
CH stretching
CO stretching
NH bending
CH bending
CN stretching
CO of polysaccharides and glucosamine rings CO stretching

A. Van Huis, F.V. Dunkel, in, 2017

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Is Chitin A Protein

Chitin is not a protein, but is similar to protein in that they are both polymers. Protein is made up of amino acids, while chitin is made up of amino sugars. So chitin wouldn’t be considered a source of protein.

Still though, chitin acts somewhat similar to certain proteins. For example, Keratin is the protein in the human body that helps to form hair and nails. However, instead of creating hair or nails, chitin generates a hard outer shell or armor in organisms for protection. Its main function in animals is primarily to hydrate and protect soft tissue.

How Can I Add Chitin To My Diet


Adding chitin to your diet is easy, just add edible crickets to your salads, roasted mealworms to your omelettes and use insects powder like cricket powder for baking , adding to shakes and generally sprinkling it on anything you want.

FUN FACT: Chitin is the second most abundant natural carbohydrate on earth after cellulose.

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Health Effects In Humans

Humans and other mammals do not produce chitin. However, they have an enzyme called chitinase that degrades it. Chitinase is present in human gastric juice, so chitin is digestible. Chitin and its degradation products are sensed in the skin, lungs, and digestive tract, initiating an immune response and potentially conferring protection against parasites. Allergies to dust mites and shellfish are often due to a chitin allergy.

Chemistry Physical Properties And Biological Function

The structure of chitin was determined by Albert Hofmann in 1929. Hofmann hydrolyzed chitin using a crude preparation of the enzyme chitinase, which he obtained from the snail Helix pomatia.

Chitin is a modified polysaccharide that contains nitrogen it is synthesized from units of N-acetyl–glucosamine -2-deoxy-D-glucose). These units form covalent –linkages . Therefore, chitin may be described as cellulose with one hydroxyl group on each monomer replaced with an acetylamine group. This allows for increased hydrogen bonding between adjacent polymers, giving the chitin-polymer matrix increased strength.

In its pure, unmodified form, chitin is translucent, pliable, resilient, and quite tough. In most arthropods, however, it is often modified, occurring largely as a component of composite materials, such as in sclerotin, a tanned proteinaceous matrix, which forms much of the exoskeleton of insects. Combined with calcium carbonate, as in the shells of crustaceans and molluscs, chitin produces a much stronger composite. This composite material is much harder and stiffer than pure chitin, and is tougher and less brittle than pure calcium carbonate. Another difference between pure and composite forms can be seen by comparing the flexible body wall of a caterpillar to the stiff, light elytron of a beetle .

Chitosan is produced commercially by deacetylation of chitin chitosan is soluble in water, while chitin is not.

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What Is A Chitin Used For

Chitin is a structural component of arthropod exoskeletons, fungi cell walls, mollusk shells, and fish scales. While humans dont produce chitin, it has uses in medicine and as a nutritional supplement. It may be used to make biodegradable plastic and surgical thread, as a food additive, and in paper manufacturing.

Facts About Chitin And Its Functions

Chitin | What is chitin? | Chitin biochemistry | Science Land
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  • B.A., Physics and Mathematics, Hastings College

Chitin is a polymer consisting of N-acetylglucosamine subunits joined by covalent –linkages. N-acetylglucosamine is a glucose derivative. Structurally, chitin is similar to the cellulose, which consists of glucose subunits and is also joined by –linkages, except one hydroxyl group on a cellulose monomer is replaced by an acetyl amine group in a chitin monomer. Functionally, chitin most closely resembles the protein keratin, which is used as a structural component in many organisms. Chitin is the second most abundant biopolymer in the world, after cellulose.

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Comparison Of Chitin Structures Using Chemical Shift Analysis

FIGURE 3. 13C chemical shift RMSD map comparing chitin structure. Data were compared between the observed 45 chitin forms in nine fungal cell walls and the three crystalline forms reported by literature . Data from six fungal species were shown, including three species of Ascomycetes , a sample from Zygomycetes , and two Ascomycetes yeast species . Most chitin types showed similarity to -chitin form. The color scale is shown, with units of ppm. Good correlation with RMSD less than 0.5 ppm are in dark blue. The forms with certain ambiguous carbon sites are labeled in italics and grey. The chemical shift values used for the analysis are provided in Supplementary Tables S2, S3.

The PCA loadings shown in Figure 4D are the weight given to each original variable in the linear combination that defines each PC, from which one can gather the relative magnitude and direction of change in those variables expected to occur over positive displacement in the respective PC score. The loadings show that while PC1 is mostly concerned with the carbonyl, PC2 focuses on the C1 atom, while PC3 and PC1 focus on C4 atom that also participates in the glycosidic linkages of chitin molecule.

Factors Affecting Chitin Degradation

Chitin degradation in soil or on artificial media can be affected by several factors, some of which are:

1. Moisture content

  • The process of chitin degradation occurs rapidly in the presence of free water and complete saturation.
  • However, the increase in the amount of water has a minimal effect on the degradation process until aeration becomes impaired due to logging.

2. Added glucose

  • The addition of glucose in the media or soil decreases the rate of chitin degradation as the organisms tend to utilize the readily available source rather than chitin.
  • Glucose is a ready energy source which is easy to metabolize. This, in turn, causes a delay or decreased chitin degradation.
  • In the absence of these sources, however, chitin degradation enhances.

3. Aeration

  • Since most of the chitinolytic microorganisms are aerobic and thrive in high-oxygen environments, the rate of chitin degradation also increases.
  • Some amount of degradation can also be observed in some concentration of CO2 as it allows facultative aerobes and anaerobes to be involved.
  • Pure oxygen environment might be toxic in some cases, especially when readily energy source is available.

4. Organic matter

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What Is Chitin Used For

While chitin is primarily used as the structural material for the organisms which weve discussed earlier and the fungi cell wall, it also has various other uses. As far as its use within different creatures, youll find it creates the teeth of molluscs and also the beaks of cephalopods. Within fish and some amphibians, it forms their scales. Chitin can be sprayed on a wide variety of plants and helps to protect them from diseases. Its used within agriculture as a fertilizer and defends plants from pests that could otherwise quickly destroy a whole crop. The reason chitin is so effective for this use is that plants have immune receptors which are activated when chitin is sprayed on them. These receptors then release hormones that encourage the immune response from the plants.

As An Emulsifying Agent


Use of food chitin can also help in creating stable food emulsions. It essentially acts as an excellent emulsifying agent, which helps to prevent the breaking of emulsion when exposed to other fluids. For instance, whipped dessert toppings often contain chitin that provides uniformity and stability to the product.

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Plants That Use Chitin In Place Of Lignin

What would the appearance and structure of trees be like if they used chitin, instead of lignin, for cell walls? This is assuming that all other properties are basically unchanged.

These trees would be in a tropical environment with nutrient rich soil and plenty of water and sunlight available. They utilize photosynthesis and have efficient vascular systems.

Would chitin effect how hard or soft they can get? Or how tall they can grow?

Spectroscopic And Structural Features Of Fungal Chitosan

Deacetylation of chitin leads to chitosan. Chitosan exists in a semicrystalline form in solids but can be solubilized by acidic solutions. In the fungal cell wall, chitosan has been proposed to serve as a backbone to bind other biomolecules, such as dityrosines or melanin . The NMR signals of chitosan are resolved from those of chitin by the absence of CH3 and CO peaks at 22 and 174 ppm . The substantial modification in the chemical structure and the hydrogen-bonding patterns induce unique chemical shifts at most carbon sites as shown by Figure 6A. The structures of two major chitosan forms, Types I and II salts with inorganic acids, have been reported , which exhibited different helical conformations . Type-I chitosan has a fully extended two-fold helical structure. The repeating unit of type-II chitosan is four times longer than that of type-I, with a relaxed two-fold helix and a tetrasaccharide repeat in a helical asymmetric unit. Overlay of the spectra predicted using the chemical shifts available in the literature and our dataset revealed that R. delemar chitosan could not structurally align with those extracted from various sources such as crab tendon, crab shell, and shrimp shell . The same discrepancy was also present for the Type-I compound, but a better correlation was observed with the Type-II structure.

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What Is Chitin In Biology

Chitin is a linear polysaccharide of the amino sugar N-acetyl glucosamine. It is present in the extracellular matrix of a variety of invertebrates including sponges, molluscs, nematodes and arthropods and fungi. Usually, chitin fibre bundles interact with chitin-binding proteins forming higher order structures.

Slime Mold Protozoa And Algae

Chitin occurs in | 11 | BIOMOLECULES | BIOLOGY | A2Z | Doubtnut
  • Myxomycetes like Physarum polycephalum are a rich source of lytic enzymes that produce a complex of extracellular chitinases.
  • Soil protozoa like Hartmanella and Schizopyrenus, along with slime mold Plasmodium are also known to produce chitinases that participate in the digestion of chitinous food particles engulfed by these invertebrates.
  • A colorless heterotrophic diatom, Nitzchiaalba, is the only known diatom to digest chitin.

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Chitin For Human Consumption

Moving away from plants and animals, chitin offers a wide range of uses for humans. Humans dont naturally produce chitin, because we have an enzyme present in our gastric juice called chitinase, which degrades chitin when it enters the body. When chitin is consumed, the lungs, digestive tract, and skin sense the chitin, which helps to initiate an immune response in the body. Chitin is often used for this reason to protect individuals against parasites. For anyone who suffers from a shellfish or dust mite allergy, this is generally due to being allergic to chitin.

Chitin is also used as a vaccine adjuvant. An adjuvant is added so that less of a vaccine is needed to stimulate the immune response. Chitin is used within the medical industry and can be added to surgical thread and bandages to strengthen these tools. On top of this, chitin is an excellent strengthening material for the paper manufacturing industry. Finally, chitin is used to improve the flavor of food and also as an emulsifier. Individuals may want to consume chitin due to its anti-inflammatory benefits, which are believed to reduce cholesterol and speed up weight loss.

What Is Chitin An Example Of

Chitin is a hard, semitransparent polysaccharide that is found in many places in the natural world, including serving as the main component of arthropod exoskeletons and the cell walls of some fungi. Chitin, for example, is the main component of the shells of crustaceans, such as crabs, lobsters, and shrimp and many insects,

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Key Takeaways: Chitin Facts

  • Chitin is a polysaccharide made of linked N-acetylglucosamine subunits. It has the chemical formula n.
  • The structure of chitin is most similar to that of cellulose. Its function is most similar to that of keratin. Chitin is a structural component of arthropod exoskeletons, fungi cell walls, mollusk shells, and fish scales.
  • While humans don’t produce chitin, it has uses in medicine and as a nutritional supplement. It may be used to make biodegradable plastic and surgical thread, as a food additive, and in paper manufacturing.

The structure of chitin was described by Albert Hoffman in 1929. The word “chitin” derives from the French word chitine and Greek word chiton, which mean “covering.” Although both words come from the same source, “chitin” should not be confused with “chiton,” which is a mollusk with a protective shell.

A related molecule is chitosan, which is made by deacetylation of chitin. Chitin is insoluble in water, while chitosan is soluble.

What Are The Byproducts Of Chitin

Chitin Definition and Examples

Unsurprisingly, chitin is quite popular in the food industry. Apart from consumption, the biopolymer is a fantastic emulsifier and stabilizer in products. Due to being antifungal, chitin also acts as a perfect edible preservation agent.

Thankfully, certain forms of chitin have great flavors. In particular, microcrystalline chitin is used as a food additive for flavor enhancement.

Chitin also has a broad application within the medical field. For example, contact lenses, artificial skin, and even dissolvable surgical stitches are derived from some form of chitin.

If you have never eaten chitin, you may have still used it. Chitin is also a major component of fertilizers. It triggers an immune response in plants, stimulating growth.

Chitin is also extremely green. The biopolymer is biodegradable, biocompatible, and non toxic. Several studies have even discovered that chitin can absorb pollutant metals from water.

Chitin doesnt harm planet Earth and even makes it a cleaner place!

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Health Effects In Plants

Plants have multiple immune receptors to chitin and its degradation products. When these receptors are activated in plants jasmonate hormones are released that initiate an immune response. This is one way plants defend themselves against insect pests. In agriculture, chitin may be used to boost plant defenses against disease and as a fertilizer.

Mechanisms Of Microbial Degradation Of Chitin

  • The vast amount of chitin produced by different sources is balanced by an equal rate of recycling of the substrate.
  • Most of the chitin degradation occurring in nature is microbial, carried out by a different group of microorganisms.
  • Chitin degradation occurs in different habitats like the sea, animal guts, and the soil.
  • Microbial chitin degradation occurs by one of the two mechanisms chitinoclastic mechanism and deacetylation mechanism.

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