Chapter - 1 : Nutrition In Plants Let’s Revise The mode of taking food by an organism and its utilisation by the body is called nutrition. Carbohydrates, fats, proteins, vitamins and minerals are the components of food and are called nutrients. The mode of nutrition in which organisms make their food themselves from simple substances is called autotrophic nutrition. The mode of nutrition in which organisms depend on others for their food is called heterotrophic nutrition. The process in which green plants make their food in the presence of sunlight using carbon dioxide and water is called photosynthesis. The bodies of living organisms are made of tiny units called cells. The leaves of plants have a green pigment called chlorophyll which is one of the essential component of photosynthesis. Leaves are food factories of plant. The synthesis of food in plants occurs in leaves. Water and minerals present in the soil are absorbed by the roots and transported to the leaves. Carbohydrate formed during photosynthesis is stored in the form of starch. Proteins are nitrogenous substances. The organisms which live on or in other animals are called the parasites. The organisms from which parasites take their food are called host. The insect eating plants are called insectivorous plants. Know the Terms Saprotrophic Nutrition : The mode of nutrition in which the organism decomposes the dead and decaying organic materials of the body by secreting enzymes and then absorbs the nutrients in solution. Saprotroph : Plants which use saprotrophic mode of nutrition. Some organisms live together and share shelter and nutrients. This is called symbiotic relationship. Lichens are the most common example of symbiotic relationship in which an algae and a fungus live together. Stomata : There are tiny pores present on the surface of the leaves for exchange of gases from atmosphere. Each pore is called stoma (stoma-singular form) and is surrounded by Guard cells. Food factory : Leaves are called the food factory of the plants because the food is prepared in the leaves. Rhizobium : Rhizobium is a bacterium which lives on root nodules of pulses and other leguminous plants. It provides nitrogen to plants by the process known as ‘nitrogen fixation‘. Legumes : The plants related to pulses and having pods are called legumes like methi, urad. Iodine test : This test is performed to detect the formation of starch in the leaves. The starch gives blue - black colour with iodine. Fertilizers : The inorganic chemical compounds prepared in the industries and rich in the nutrients are called fertilizers. 2 ] Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII Flowchart Nutrition Nutrition Autotrophic Heterotrophic Process of making food Parasitic Saprophytic Photosynthesis Chlorophyll Sunlight Insectivorous Symbiosis Chapter - 2 : Nutrition In Animals Let’s Revise Animals are heterotrophic in their mode of nutrition because they cannot prepare their own food. Most of the animals take food in the form of solids and this process of nutrition is called holozoic nutrition. Holozoic mode of nutrition has the following steps : (a) Ingestion (b) Digestion (c) Absorption (d) Assimilation (e) Egestion The alimentary canal of humans can be divided into following parts : (a) Buccal cavity (b) Oesophagus (food pipe) (c) Stomach (d) Small intestine (e) Large intestine (f) Anus. The undigested and unabsorbed residues are expelled out of the body as faeces through the anus. Amoeba ingests its food with the help of its false feet or pseudopodia. The food is digested in the food vacuole. Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII [ 3 Ectoplasm Endoplasm Mitochondria Nucleus Crystals Food vacuole Advancing pseudopod Contractile vacuole Fig. Amoeba Know the Terms Buccal cavity : The cavity of mouth, with all its internal parts like cheeks, teeth, tongue and salivary glands is called buccal cavity. Cellulose : A type of carbohydrate. Many animals including human cannot digest cellulose. Glycerol : It is one of the constituents of fat. It combines with fatty acid to from fats. Fatty Acids : One of the main constituents of fats. Ingestion : Process of taking food into the body. Digestion : The breakdown of complex components of food (which cannot be utilised by our body) into simpler and absorbable substances is called digestion. Absorption : The passage of digested food into the blood vessels is called absorption of food. This process takes place in the small intestine in case of human beings. Assimilation : The process in which the absorbed food is used for producing energy and growth is called assimilation. Egestion : The removal of undigested and unabsorbed food material, called faecal matter through the anus from time to time is called egestion. Arrangement of different types of teeth : Fig. : Types of Teeth Types of teeth with functions : Number in each Types of Teeth Structure Function half of the jaw Incisors (Front teeth) 1 Have flat, sharp edges Cutting and biting the food. Canines 2 Sharp and conical Tearing and piercing Premolars 2 Bicuspids and have one or Crushing and grinding two roots Molars 3 Four or five cusps, have more Crushing, grinding and mastication than one root 4 ] Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII Number and types of teeth in man Types of Teeth Milk teeth Permanent teeth Incisor 4 4 Canine 8 8 Premolar 8 8 Molar 0 12 Total number of teeth 20 32 Tooth decay : After eating food, especially sweets, chocolates, cold drink and other sugars, if mouth is not washed properly, then some leftover food and sugars remain attached to teeth. The harmful bacteria break down the sugars and release acids. The acids gradually damage the teeth. This is called tooth decay which may lead to toothache and even loss of tooth. Amazing fact Starfish feeds on animals covered by hard shells of calcium carbonate. Fig. : Starfish ORS (Oral Rehydration Solution) : It is prepared by dissolving a pinch of salt and sugar in boiled and cooled water. It prevents dehydration of the body due to diarrhoea and vomiting. Flowchart Nutrition in Animals Classification Based Utilisation/Digestion on Eating Habits in Body Digestion is the breakdown of complex components of food Herbivorous into simpler substances. In Humans Carnivorous Omnivorous Parasites In Grass-eating Animals In Amoeba Scavengers Nutrition in Animals Classification Based Utilisation/Digestion on Eating Habits in Body Digestion is the breakdown of complex components of food Herbivorous into simpler substances. In Humans Carnivorous Omnivorous Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII [ 5 Parasites In Grass-eating Animals In Amoeba Scavengers Chapter - 3 : Fibre to Fabric Let’s Revise The fibres obtained from animals are called animal fibres. Example, wool and silk. Wool is obtained from the fleece (hairy growth) of animals such as goat, sheep, yak, alpaca, llama, lamb. The wool yielding animals have a thick coat of hair which traps a lot of air. Being poor conductor of heat, hairs keep these animals warm. The fine soft hair fibres are used for making wool. Some Indian Breeds of Sheep S. No. Name of breed Quality of wool State where found 1. Lohi Good quality wool Rajasthan, Punjab 2. Rampur bushair Brown fleece Uttar Pradesh, Himachal Pradesh 3. Nali Carpet wool Rajasthan, Haryana, Punjab 4. Bakharwal For woollen shawls Jammu and Kashmir 5. Marwari Coarse wool Gujarat 6. Patanwadi For hosiery Gujarat Processing fibres into wool involves the following steps : The fleece of the sheep along with a thin layer of skin is removed by machines. This process is called shearing. The sheared hair is thoroughly washed in tanks to remove grease, dust and dirt. This process is called scouring. Clean hairy skin is sent to the factory where hair of different textures are sorted (separated). This is called sorting. The small fluffy fibres, called burrs, are picked out from the hair. The natural fleece of sheep and goats is black, white or brown. So, the fibres are dyed in various colours. The fibres are straightened, combed and rolled into yarn. The shorter fibres are spun and woven into woollen clothes. The longer fibres are made into wool for sweaters. Silk fibre is obtained from the cocoon of the silk moth. The breeding and management of silkworms for production of silk is called sericulture. 6 ] Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII Know the Terms Selective breeding : Some breeds of sheep possess only fine under - hair. The process of selecting parents is termed as selective breeding. Silk : It is a natural protein fibre, some forms of which can be woven into textiles. Sericulture : The breeding and management of silkworms for the production of silk is known as sericulture. Life cycle of silk moth : There are four stages in the development of silk moth : Eggs → Caterpillars → Pupa → Silk moth Silkworm (Adult) (larva) Discovery of silk : Silk is supposed to be discovered in China. Accidentally, a cocoon dropped into the cup of tea of empress silung-chi, and a tangle of delicate threads separated from the cocoon. Silk industry began in China and was left a closely guarded secret for hundreds of years. Later on, traders and travellers introduced silk to other countries. The route they travelled is still called the ‘Silk route’. Flowchart Fibres Long, fine, continuous threads or filaments are obtained from plants and animals. Animal Fibres Plant Fibres Silk Wool Sources of Silk Processing of Silk Fibre Sources of Wool Wool is obtained from sheep. yak (Tibet and Ladakh), Angora goat, goat, camels, llama andAlpaca, (SouthAmerica) Obtaining Wool Fibre Obtaining Silk Fibre Shearing : Fleece of the sheep along with a thin layer of skin is removed from its body. Processing of Wool Fibre Oswaal CBSE Chapterwise Quick Review, SCIENCE, Class-VII [ 7 Chapter - 4 : Heat Let’s Revise A reliable measure of the hotness of an object is its temperature. Temperature is measured by a device called thermometer.