Domesticated silkworms are not anymore found in the wild. (d) True Scouring is the process to clean sheared hair. (c) MULBERRY History of silk: Around 3500 BC, silk was discovered in China during the reign of emperor Huang-ti. (c) fleece (hair) i. Silkworms secrete fibre made of (a) fat (b) cellulose (c) protein (d) nylon ii. (d) REELING. (d) production of sarees. It was considered as one of the most valuable fibre … (d) the process of taking silk threads from cocoon. (f) Cocoons are kept under the sun or boiled in water. They grow in size and when the caterpillar is ready to enter the next stage of its life history called (f)……………. Answer: (c) weaving of silk cloth. A single fibre is too weak to break but when some fibres together make a fabric, it is difficult to tear. (b) rearing of silkworm. (e) Yak hair are not used to make woollen fabric. (b) cocoon, worm Nylon. On issuing into the air, the fine stream is hardened into the silk fiber, which the caterpillar spins into a cocoon. Answer: (a) culture of bacteria (d) Reeling of silk is the process of taking out threads from the cocoon for use as silk. The rearing of silkworms for obtaining silk is called Fleece of sheep gives wool, cotton ball gives cotton and jute stalk gives jute fibre. Rearing of silkworm. Perhaps the best-known of these larvae are the mulberry silkworm Bombyx mori which are raised in captivity for their silk fiber (sericulture). Question 12: Write them in their correct form. (d) production of sarees Answer: Discovery and Sources of Silk Silk was first developed in china. (d) the process of taking silk threads from cocoon. The most common variety of silk is – (a) Tussar silk (b) Kota silk (c) Mulberry silk (d) Mooga silk iv. (a) Mulberry silk … (b)  Silkworm Nylon is a synthetic fibre. (a) and________ fibres are obtained from animals. (d)  Cocoon with developing moth. Answer: B. Write the above steps in the correct sequence in which they are carried out. (b) rearing of silkworm Question 9: Reeling of silk is. (c) Wool yielding animals bear________ on their body. Silkworms spin composites of two silk fibers out of two converging silk glands. Class 7 Science Chapter 3 MCQ (Multiple Choice Questions) of Fibre to Fabric. (d) Hair trap a lot of________ which is a poor_________ of heat. (i) Shearing The first step is to remove fleece of the sheep along with thin layer of skin. Silkworm and Tasar Cocoon” is carried out by Sahana R, ... secrete the liquid silk during the spinning, ... the leftover is fibroin made up of two brins. (d)…… or (e)……….. This process is called shearing. These solutions for Animal Fibres Wool And Silk are extremely popular among Class 7 students for Science Animal Fibres Wool And Silk Solutions come handy for quickly completing your homework and preparing for exams. (d) Scouring (c) Animal fur cap (b) hen certain desired traits (properties) of parents are considered before breeding, it is called selective breeding. (d) silviculture Answer: Question 1: Answer: Scientists have long envied the lowly silkworm's ability to spin the strongest natural fiber known to man. Give reason for your answer. CBSE Maths notes, CBSE physics notes, CBSE chemistry notes. Some, for example, are hydrophilic (water loving), whereas others are hydrophobic (water fearing). The origins of silk date back to Ancient China. Fat and cellulose are not present in silk. (d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves. (a) SERICULTURE Very Short Answer Type Questions. (b) WILSMORK Making silk fabric from silk yarn. Within the cocoon the caterpillar is presently transformed into the chrysalis or pupa. Life cycle of silk worm 14. So, on burning these threads, a smell of burning hair comes out. Find the names of these animals. Wool fibre cannot be obtained from which of the following? The process of taking silk threads from cocoon. (a) TURECULRISE Arrange them in their proper sequence. Question 11: Fill in the blanks in … (c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons. If false, correct them. Fill in the blanks in the following statements. Silkworms secrete fibre made of Some of these letters in each ring can form the name of one wool yielding animal. Silkworm silk fiber is composed of a fibroin core and a sericin casing, and is relatively rigid because the sericin causes the filaments to adhere to one another. Answer: The term sericulture is used for The rearing of silk moths for obtaining silk is called sericulture. All the chapter wise questions with solutions to help you to revise the complete CBSE syllabus and score more marks in Your board examinations. (c)  Cocoon Answer: (e) Sorting This aggregation allows the proteins to stay soluble and avoid premature crystallization. Use the coupons before they're expired for the year 2020. Spinning of silk fibres. Very Short Answer Type Questions. FIBRE TO FABRIC Silk Silk, another animal fibre having animal protein is obtained from the cocoon of silk moth (or silkworm). Steps for the production of silk are given below in a jumbled order. Introduction: Silk is a natural protein fiber, produced by insect larvae to form cocoons. The (a)……… silk moth lays (b)……… from which hatch (c)……….. called Silkworms secrete fibre made of (a) fat (b) cellulose (c) protein (d) nylon. These silk-producing glands secrete a clear liquid that hardens into a thin silk thread when it comes into contact with air. (c) Sericulture is a practice of rearing silkworms for obtaining silk while silviculture is a practice of developing and caring forests. Complete the paragraph related to the life history of silk moth by filling in the blanks. Caterpillars continue to spin silk fibre till they completely get covered by these fibres. (b) cotton ball Question 17: (b) Silk scarf The GM silkworms secrete fibres made of spider web protein (spider silk), which is stronger than normal silk fibre protein. Examples of natural fibers are cotton and silk whereas examples of synthetic fibers are: nylon, polyester, etc. Still, the ones in the wild are more adaptive to nature compared to the domestic ones. Production of sarees. Answer: D. Question 10: Silkworms secrete fibre made of. Question 3: A wholesale woollen fibre dealer gets the woollen fibre of different textures sorted for various purposes. Which of the following makes silk fibres – (a) Larva (b) Adult silk moth (c) Pupa (d) None of the above iii. This silk covering in which a silkworm … (ii) Scouring In this step, the sheared hair is washed thoroughly to remove grease, dust and dirt. Answer: (b) False, sheep are mostly reared for wool in India. (c) selecting an area for breeding She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. Fat. Pupa develop inside cocoon into moth and comes out as an adult male or female silk moth. (d) Moth silk (b)  Tassarsilk Selective breeding is a process of Question 6: Reeling of silk is (b)  silk The life cycle of silk moth is completed in four main stages as depicted below in the diagram: Answer: Scientists have produced genetically modified (GM) silkworms that contain a gene from a spider. In the new work, David L. Kaplan and Hyoung-Joon Jin of Tufts University dissolved silk from a cocoon and removed the compounds responsible for gluing the fibers together. (a) cocoon Fat and cellulose are not present in silk. The correct order is ... secrete fibres made of protein (fibrin) with their special silk glands. Since, cotton and paper both are carbohydrates and on burning, they give similar smell. Silk is a type of natural fiber or animal fiber. A fibre is a hair-like strand of material. Scientists have known for some time that silk's impressive strengths arise from a mix of proteins with various properties. (d) Leather jacket (a) female  (b) eggs   (c) larvae (d) caterpillars (e) silkworm   (f) pupa (g) cocoon. State whether the following statements are True or False. (a) Picking out the burrs (b) Fibres are taken out from the cocoon. Answer: Cellulose. Question 10: 10. (c) making silk fabric from silk yarn. (a) fleece of sheep Silkworm is a classic side scrolling shooter, developed by Tecmo and first released for arcade in 1988.In 1989 it was ported to the Amiga, Atari ST, Commodore 64, ZX Spectrum, Amstrad CPC and NES (1990) systems by The Sales Curve and released by Virgin Mastertronic.. Silkworm also spawned what many consider to be a spiritual successor to the game - SWIV. Silk fibre can be Paheli wanted to buy a gift made of animal fibre obtained without killing the animal. The various steps for processing fibres into wool are as follows: (c) Shearing A material which is composed of thin and continuous strands is known as fiber. Clothes made from Silk and other things are liked by everyone because of its texture. Ancient literature, however, attributes the popularization of silk to the Chinese Empress Si-Ling, to around 2600 B.C. During these movements, caterpillars secrete a fibre made of protein, which solidifies and hardens when exposed to air for some time. Which thread is from a pure cotton saree and which one from a pure silk saree? Fabric needs more energy to tear apart as compared to a single fibre. (a) Goat The silkworm has two modified salivary glands near its lower jaw called sericteries. Silk protein consists of sericin and fibroin mainly. Comprised of a natural protein fiber, silk mainly consists of fibroin, which is a protein that certain types of insect larvae secrete to make cocoons. Note Yak are found in Tibet and Ladakh, while angora goats are reared in Jammu and Kashmir. Although cocoon coverings of fiber are made by a large number of insects. Periods between moults are known as silkworm instars. 9.04.2.1 Silkworm Silk. There aren’t any genetic or morphological differences between domestic & wild silkworms. Silk has set the standard in luxury fabrics for several millennia. (b) Silk fibres come from________ of silk_________ . SERICULTURE • Sericulture, or the raising of silkworms, involves the incubation of the tiny eggs of the silkworm moth until … Fibres can be spun into yarn and made into fabric. Which of the following is not a type of silk? A process of making silk reels. (a) Silkworms are caterpillars of silk moth. (c) weaving of silk cloth (a) selecting the offsprings with desired properties Silkworm is … Silk’s softness has made it a hotly desired commodity throughout history, and this simple fiber has built legendary trade routes and transformed cultures throughout the Old World. If the proteins were to become solid too soon in silk-producing animals, they could permanently block the spinning system, with potentially fatal results. (iv) Separating burrs Burrs are small fluffy fibres which are picked out from the hair. NCERT Solutions for Class 7 Science Chapter 3 Animal Fibres Wool And Silk are provided here with simple step-by-step explanations. (d) Moth is an insect while other three are the animals with fur which produce wool. (e) Female silk moths lay eggs. (c) protein Answer: The correct sequence is (a) Woollen shawl Weaving of silk cloth. Discover world-changing science. (c) making silk fabric from silk yarn. (a) Eggs of silk moth on mulberry leaf Write a caption for each of the figure given as figure (a-d). Which of the following would be the right gift for her to buy? (v) Dyeing The fibres are dyed in various colours, as the original colours of fleece are usually black, white or brown. The general process that takes place at a sheep shearing shed is Match the items of Column I with the items given in Column II. Answer: Describe the life history of silk moth with the help of figures of various stages. Answer: Silkworm moths go through four stages of development – egg, larva, pupa and adult – as do the majority of insects. Silk is a natural protein fibre which can be used as a textile fibre. Nylon is a synthetic fibre. Protein. (b) selecting the parents with desired properties 13. Answer: (c) cocoon (e) False, wool can be made from sheep, yak, llama, camel, alpaca and goats. They then examined how the remaining proteins behaved in the presence of various amounts of water. 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