Many hundreds of strains are maintained, and over 400 Mendelian mutations have been described. 4 Structure of fibres A fibre is defined as a unit of matter with a length at least 100 times its diameter, a structure of long chain Fat and cellulose are not present in silk. fat; cellulose; protein; nylon; Answer. (a) selecting the offsprings with desired properties. Your email address will not be published. When the silk ran out, she saw a small larva. Quantity of cocoon and silk produced are directly related to the pupation rate and larval weight. This led to Gandhi's promotion of cotton spinning machines, an example of which can be seen at the Gandhi Institute,[7] and an extension of this principle has led to the modern production practice known as Ahimsa silk, which is wild silk (from wild and semiwild silk moths) made from the cocoons of moths that are allowed to emerge before the silk is harvested. Naked and cold, she spit out the net and used it as a blanket to sleep. Explanations are provided for MCQS and true or false type questions. Often, the silkworm itself is eaten. #manufacturing #fabric #eco #silkworms. Cellulose. They grow in size and when the caterpillar is ready to enter the next stage of its life history called ___(f)____, it first weaves a covering to hold itself, which is known as ___(g)____. Usually, hair is removed during the hot weather. [10] One useful development for the silk industry is silkworms that can feed on food other than mulberry leaves, including an artificial diet. Mahatma Gandhi was critical of silk production based on the Ahimsa philosophy "not to hurt any living thing". Woollen fibres are then processed to obtain woollen yarn. Viscose is a fiber made of regenerated cellulose fibers. Children often pass on the eggs, creating a non-commercial population. Machines similar to those used by barbers are used to shave off hair. The larvae then prepare to enter the pupal phase of their lifecycle, and enclose themselves in a cocoon made up of raw silk produced by the salivary glands. [9] Research on the genome also raises the possibility of genetically engineering silkworms to produce proteins, including pharmacological drugs, in the place of silk proteins. (b) Silk fibres come from _________ of silk _________. During these movements of the head te silkworm secretes fibre made of a protein which harden on exposure to air and becomes silk fibre. Many other Lepidoptera produce cocoons, but only a few—the Bombycidae, in particular the genus Bombyx, and the Saturniidae, in particular the genus Antheraea—have been exploited for fabric production. The domesticated B. mori and the wild B. mandarina can still breed and sometimes produce hybrids. A moth is a type of insect. [citation needed] One example of this was the molecular identification of the first known pheromone, bombykol, which required extracts from 500,000 individuals, due to the very small quantities of pheromone produced by any individual silkworm. Silk is obtained after killing silkworm, Animal fur cap is obtained from fur which requires the killing of an animal. … Arrange them in their proper sequence. Which of the following would be the right gift for her to buy? Explain the phrase – “Unity is Strength” on the basis of the making of fabric from the fibre. For more information visit BYJU’S website or download BYJU’S learning App. Researchers at the MIT Media Lab experimented with silkworms to see what they would weave when left on surfaces with different curvatures. (e) Yak hair is not used to make woollen fabric. Class 7 Science Chapter 3 MCQ (Multiple Choice Questions) of Fibre to Fabric. Life Cycle 5. Some words related to silk are jumbled up. [21][22] Since then, the silk production capacity of the species has increased nearly tenfold. Other Silkworm Moths. Yarns are then woven, knitted or bonded into fabric. Bombyx mori, the domestic silk moth, is an insect from the moth family Bombycidae.It is the closest relative of Bombyx mandarina, the wild silk moth.The silkworm is the larva or caterpillar of a silk moth. (c) making silk fabric from silk yarn. The univoltine type is generally linked with the geographical area within greater Europe. [11], Kraig Biocraft Laboratories[12] The rearing of silkworms for obtaining silk is called. [27] Major questions, however, remain unanswered, according to Jun Wang, co-author of a related study published in 2008,[28] who stated: "Whether this event was in a single location or in a short period of time in several locations cannot be deciphered from the data",[29] and research also has yet to identify the area in China where domestication arose. 21. (b) rearing of silkworm. 9. (b) separating the hair of different textures. Cellulose is an excellent fiber. Habit and Habitat of Mulberry Silkworm 3. (d) Hair trap a lot of _________, which is a poor _________ of heat. Wool can be obtained from animals like sheep, goat, camel, yak, rabbit, etc. The general process that takes place at a sheep shearing shed is. The polyvoltine type of mulberry silkworm can only be found in the tropics. (d) production of sarees. (b) spinning of silk fibres. If the animal is allowed to survive after spinning its cocoon and through the pupal phase of its lifecycle, it releases proteolytic enzymes to make a hole in the cocoon so it can emerge as an adult moth. Answer: D. Question 10: Silkworms secrete fibre made of. (c) making silk fabric from silk yarn. Answer: B. (b) rearing of silkworm. They are implanted during reconstructive surgery to support or restructure damaged ligaments, tendons, and other tissue. The domestic silk moth derives from Chinese rather than Japanese or Korean stock. They are covered with tiny black hairs. 15. This is called scouring. [4]:342, Domestic silk moths are very different from most members in the genus Bombyx; not only have they lost the ability to fly, but their color pigments have also been lost. After molting, the larval phase of the silkworms emerge white, naked, and with little horns on their backs. Hair are of bad conductors of heat, hence they will not allow the escape of heat from the body, which ensures their bodies stay warm. Shearing does not hurt the sheep just as it does not hurt when you get a hair cut or your father shaves his beard. It is easy to break a fibre thread as it is fragile and easy to break as well. 1. This enables sheep to survive without their protective coat of hair. It has gained tolerance to human presence and handling, and also to living in crowded conditions. Removal of fleece from sheep is known as shearing. (d) the process of taking silk threads from cocoon. 3. (d) the process of taking silk threads from cocoon. These are the same burrs which sometimes appear on your sweaters. In addition, antibiotics with appropriate pharmacokinetic parameters were selected that correlated with therapeutic activity in the silkworm infection model.[19]. Explanation: A salivary gland of silkworm releases a protein which is used as silk. Soln: The answer is (c) protein. Steps for the production of silk are given below in a jumbled order. The silkworm is the larva or caterpillar of a silk moth. They grow in size and when the caterpillar is ready to enter the next stage of its life history called f) pupa, it first weaves a covering to hold itself, which is known as g) cocoon. In commercial use, silk is almost entirely limited to filaments from the cocoons of domesticated silkworms (caterpillars of several moth species belonging to the genus Bombyx ). Algae based fibre 4. Selective breeding is the process of the crossing of two selected varieties having different traits to produce a hybrid having good traits of both, e.g., some breeds of sheep possess only soft under-hair. [5], Mulberry silkworms can be categorized into three different but connected groups or types. Spinning of silk fibres. The Chinese guarded their knowledge of silk, but, according to one story, a Chinese princess given in marriage to a Khotan prince brought to the oasis the secret of silk manufacture, "hiding silkworms in her hair as part of her dowry", probably in the first half of the first century AD. (c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons. Using this knowledge they built a silk pavilion with 6,500 silkworms over a number of days. Freshly chopped mulberry leaves, and other tissue over a number of factors, including genetics given here those by. The larva or caterpillar of a protein which is further processed to … 10 hair. 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