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Class 10 CBSE Notes 2017 : Biology

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NUTRITION IN PLANTS AND ANIMALS Nutrition includes the nutrients necessary for the growth, maintenance, and reproduction. All living organisms require food for their survival. There is a large variety of living organisms. These include Microorganisms, Plants and Animals. All living organisms perform activities. These include movement of limbs, respiration, digestion and circulation. Think? a. What gives us energy for performing various life processes? b. What happens when you work rigorously without having a meal? c. Does a non-living thing also need energy? MODES OF NUTRITION: Mode of nutrition helps to classify organisms that use simple raw materials or readymade complex material as their food. It shows different kind of relationship between organisms. Different habitats display these relationships in unique way. The living world has organisms that show mainly two modes of nutrition autotrophic and heterotrophic. Living organisms which can prepare their own food by the simplest raw materials available are called autotrophs and the mode of nutrition is known as autotrophic mode. On the other hand the organisms which depend on other living organisms for food are called heterotrophs and the mode of nutrition is called heterotrophic. While plants prepare their own food from raw materials like carbon dioxide and water in the presence of sunlight, humans prepare their food from plant products or animal products by different ways of cooking. These are boiling, frying, roasting and steaming. Autotrophic mode of nutrition: Autotrophs use carbon dioxide from air and water from soil to convert it to glucose and oxygen. It is observed in all plants, alga and some bacteria. Two types of autotrophs are a. Photo-autotrophs- These organisms derive their energy from sunlight. For exampleGreen Plants. b. Chemo-autotrophs- These organisms use chemical energy. For example-Nitrifying bacteria Is it not a wonder to know that plants can prepare their food with the help of air, water and sunlight? What is the special feature present in the plants that makes this happen? CLASS 7 WWW.SCHOLAR-MINDS.COM 1 Usually, plants are green in colour. This colour is because of a pigment called chlorophyll. It traps the sunlight to convert carbon dioxide and water into oxygen and glucose. We can accept, all green plants prepare their own food from simple raw materials available from the soil and the atmosphere. The process of preparation of food by the plants is called photosynthesis. Plants require carbon dioxide, water, energy and chlorophyll. Where do these come from? Carbon dioxide as we know is present in air around us. Water is present in the soil. The energy comes from sunlight and the green pigment is present in plants especially in the leaves. Where does the raw material get collected in the plants? Photosynthesis is the process of preparation of food by plants. Photo means light and synthesis means combination of components to prepare something. Most plants can prepare their food without much dependence on other living organisms. They are called autotrophs. Do plants have a nose to take in oxygen and carbon dioxide from air? Take a leaf of Rhoeo plant and gently scrap a thin peel from its upper surface using needle and a forcep. Gently hold the peel with a brush and put it into a Petridis having water so that the cell do not get dry. Put a drop of glycerine on a glass slide and then gently place the peel. Place the cover slip and observe under microscope. What do we notice? The layers of cells in the peel are interrupted by small openings present here and there. These are called stomata. These pores help in taking in carbon dioxide from the atmosphere. Careful observation under the microscope shows the following structure. We find different type of cells in the slide. Focus on the guard cell structures. These are like p o r e s in our skin. They appear in the peel of the leaf. The pores help in exchange of gases with the atmosphere. Carbon dioxide enters through the pores. Water, which is the other requirement of photosynthesis, is absorbed by the roots of the plant and transported to the leaves through specialized cells. Using the energy from the sun, a chemical reaction takes place in the chlorophyll containing parts (green parts) of the leaves in which carbon dioxide and water are converted into food which is glucose (a simple sugar) and oxygen gas is released in the process. The glucose gets stored in the leaf as starch (a type of carbohydrate). The food manufactured in the leaves in the form of glucose or starch is transported to other parts of the plant through stem. Leaf a manufacturing unit of the plant or the food factory of the plant. CLASS 7 WWW.SCHOLAR-MINDS.COM 2 Carbohydrates in the form of glucose are the products of photosynthesis which gets converted into starch, the first visible product of photosynthesis. It is therefore possible to find out if a plant has carried out photosynthesis by testing for starch. Presence of starch Implies that photosynthesis has occurred. Fact file In a single year, one hectare of forest absorbs about 22 tonnes of carbon dioxide and gives out 16 tonnes of oxygen every year. ACTIVITY 1: Aim: To test the presence of starch in a leaf. Procedure: Half fill a beaker with water and boil the water. Place the leaf in boiling water for one or two minutes. This stops chemical reactions. Put the leaf into a boiling tube and pour enough ethanol to cover the leaf. Place the boiling tube into the beaker of boiling water. A water bath is used to prevent accidents that may arise from alcohol (being inflammable). CLASS 7 WWW.SCHOLAR-MINDS.COM 3 Remove the flame when the ethanol boils. Re-introduce the flame when the ethanol stops boiling. Repeat until the leaf is decolorized. (The green color gets totally removed.) Re-introduce the flame when the ethanol stops boiling. Repeat until the leaf is decolorized. (The green color gets totally removed.) When the chlorophyll has been removed (the leaf looks white) remove the leaf from ethanol (the leaf will be brittle). Put the leaf in a petridish having water to soften the leaf and pour two four drops of iodine onto the surface of the leaf. The appearance of blue black color indicates the presence of starch. ACTIVITY 2: Aim: To show that light is necessary for Photosynthesis. Materials required: Well watered potted plant, dark paper, scissors/knife, pins. Steps: 1) Fix the paper on one of the leaves as shown in the diagram. 2) This experimental setup is exposed to sunlight for 2-6 hours. 3) The paper is removed and the leaf is tested for starch. CLASS 7 WWW.SCHOLAR-MINDS.COM 4 Conclusion: Starch is produced only in areas that received light, showing that light is necessary for photosynthesis. Suggestion: Variously colored leaves could be taken to perform starch test that could enable us to prove that colored parts photosynthesize. ACTIVITY 3: Aim: To show that chlorophyll is necessary for photosynthesis. Method / procedure: 1. Take a green, a variegated and a colored leaf from the plants that have been de- starched. 2. Make a rough sketch of a variegated leaf showing the green and non-green parts. 3. Boil each of the leaves in ethanol as done in the previous activities to remove the chlorophyll. 4. Test each of the leaves for starch and record your observation in the following table. Type of leaf Colour with iodine Presence of starch Green Variegated CLASS 7 WWW.SCHOLAR-MINDS.COM 5 Leaf of a croton (pink / purple) You will observe that the leaf which is green gives positive test for starch. This shows that the process of photosynthesis took place. The variegated leaf gives the positive test for starch only in the regions which were green before boiling. The leaf having other pigments also gives the positive test for starch which shows that chlorophyll is present but is masked by the other c o l o r e d pigments. Now that we know what are the materials needed for photosynthesis and the end products of photosynthesis, let us try to fill in the d e t a ils to complete the word equation for photosynthesis. Carbon dioxide + water in the presence of + oxygen Plants release oxygen and this is the reason why we feel fresher when we are in a garden than on the road. The oxygen which is released during the process is the supporter of life on the earth Autotrophs (plants) as producers of food: The food that is manufactured by plants is not only used by the plant but by the entire living world directly or indirectly. A .. Heterotrophic autotrophs! Animals feed on plants or other animals for food and energy, but some researchers are studying a sea slug that can produce its own energy through photosynthesis. The sea slug eats algae but does not fully digest it. What remains in its system continues to photosynthesize and provide food for the slug, similar to what a plant does. Find out more about sea slugs. HETERETROPHIC NUTRITION IN PLANTS Hetero means another and trophe means nutrition. Certain plants use different mechanisms, other than photosynthesis to obtain their nutrition. They depend on other organisms for their food. These plants show heterotrophic mode of nutrition. Do plants and animals use similar kind of food? What happens to the food prepared by plants? A part of the prepared food is used by the plant for its survival. Rest of the food is stored in different parts of the plant body. Both plants and animals derive food from glucose. In anim als food is broken down to glucose. In plants the raw materials are processed to give glucose. Heterotrophic mode of nutrition can be seen in different forms CLASS 7 WWW.SCHOLAR-MINDS.COM 6 i) ii) iii) iv) Parasitic mode Saprophytic mode Carnivorous mode Symbiotic mode PARASITIC MODE: The word parasite is derived from Latin word parasitus which means "feeding on another living organism". Lice is a familiar example of an animal parasite. It feeds on the blood of other organisms, human or cattle. In this process, it harms the other organisms o n which it feeds. Similarly, there are certain plants like cuscuta that depends on other plants for their nutrition. These parasitic plants do not have enough chlorophyll. They are pale yellow in colour. They have special structures that help them to extract nutrition from other plants. In parasitic mode of nutrition the organism which derives nutrients is called a Parasite. The organism which the parasite depends is called a Host. Look at the following parasitic plant MISTLETOE These plants have green leathery leaves which can make their own food. Then why do we consider it as parasitic plant? The reason is that this plant is dependent on host plant for minerals and water but not for food. Such plants are called partial parasitic plants while the ones like cuscuta and Apodhanthus are complete parasitic plants. Parasitic plants have specialized structures called haustoria to obtain food from their host plants. SAPROTROPHIC MODE: You must have seen moulds growing on a stale piece of bread and mushrooms growing on rotten material. Have you ever wondered from where these plants obtain their nutrition? CLASS Class VII 7 WWW.SCHOLAR-MINDS.COM 7 WWW.SCHOLAR-MINDS.COM 10 They grow on dead organic matter and obtain their food from them only, such mode of nutrition is called saprophytic nutrition and such plants are called saprophytes. These plants releases enzymes outside their body, digest the organic matter and absorb them. This is called extracellular digestion. Saprophytes (sapros-rotten, phyte-plants) are decomposers. Dead organism s breakdown c o m p l e x organic matter for their use. In exchange they release vital chemicals into the soil. These are absorbed and used by autotrophs. We can say that saprotrophs help reuse and recycle the organic material. ACTIVITY 4: Aim: To make a slide of bread mould. Take a piece of moist bread and keep it inside the box for 2 to 3 hours. Observation: You will see a black or white cottony growth over it. This is bread mould. Scrap it lightly with a needle and place it on a slide. Keep the slide under the microscope and you can see a filamentous structure. No plant has yet been found which can use dead organic matter for food directly. In fact it is the fungi present in roots that are capable of digesting dead and decaying matter CARNIVOROUS PLANTS: In some areas soil is deficient in certain nutrients, especially nitrogen. Hence plants growing in such areas need to obtain same from other sources. Insectivorous plants Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Some examples are pitcher plants, Sundew and Venus Fly trap. CLASS 7 WWW.SCHOLAR-MINDS.COM 8 Modifications present in insectivorous plants: Observe the photograph of a pitcher plant given above. The pitcher like modifications of the leaf apex has a specific function. What could it be? It might help you to know that pitcher plant grows in soil deficient in nitrogen. Nitrogen is an essential nutrient for both plants and animals. The pitcher like structure has hair like extensions to trap insects. It is amazing to observe that as soon as the insect gets trapped, the lid closes. The entrapped insect is digested by the action of digestive juice secreted w i t h i n the pitcher. Plants need for nitrogen is supplied by the digested insects. Unlike parasitic plants like c u s c u t a , the pitcher plant has chlorophyll. SYMBIOTIC PLANTS: Some symbiotic plants demonstrate a win-win kind of interdependence. The most beautiful aspect is that this interdependence can be between a plant and bacteria or plant and fungus. Symbiotic relationship is a close association between individuals of different species. The relationship is based on the nutritional benefits they derive from each other. For Example-Rhizobium and Legume plants a gram and pea plants are common examples of legumes. Legumes growing in soil develop modules in their roots which harbor bacteria called Rhizobium. The bacterium has the ability to convert nitrogen from the air to an absorbable form. While the bacteria provide usable nitrogen for the plant, in return it gets appropriate condition f o r its survival in the root nodule. The world of plants is diverse in numerous ways. One such way is the mode of nutrition. The most wellknown example of a symbiosis is that of fungi and algae is the lichen. The fungus component of the lichen is referred to as the mycobiont and the algal component is called phycobiont. The algal partner makes food and provides it to fungus and in return fungus provides water, minerals and shelter to alga. Lichen acts as a pollution Indicator NUTRITION IN ANIMALS: We know food is essential for all living organisms. Some people like to eat sweets, chocolates fizzy drinks, chips, some like to eat fruits and green vegetables; still others like t o eat rice, milk, and fish. Different people have different food habits. Do you think we should eat food for its taste or plan a diet considering the essential components of food f o r healthy growth of our body? Components of food: Components of food required by our body for its healthy growth are called nutrients. CLASS 7 WWW.SCHOLAR-MINDS.COM 9 ESSENTIAL COMPONENTS OF FOOD Thus we can conclude that: 1. Food such as Rice, Chapatti, bread are energy giving and known as Carbohydrates. 2. Milk, eggs, meat help in body building and are known as Proteins. 3. Vegetables and fruits are rich in minerals and vitamins and protect us from diseases. CLASS 7 WWW.SCHOLAR-MINDS.COM 10 4. Butter and ghee as source of stored energy, are known as fats. 5. Water is also an essential component of food. Modes of Nutrition Modes of nutrition in all living organisms can be divided into two categories 1. Autotrophic nutrition. 2. Heterotrophic nutrition. Organism such as plants which make their food from simple substance such as Carbon dioxide, Water and sunlight are called producers or Autotrophs. Animals cannot make their own food but depend upon others for their food. This mode of nutrition is called Heterotrophic Nutrition. Therefore all animals including human s beings are called Heterotrophs. Whatever be the source of food and the mode of feeding, do you think that the food gives u s energy as soon as we consume it? Of course not. Let us now understand the process of nutrition. It will be interesting to note that food does not give us energy even on reaching the stomach. The food is first broken down into simpler forms, and then absorbed by the body cells through blood. It then gets oxidized with O2 to release energy. Digestive system includes intake of food ingestion, digestion of food Digestion, Absorption and Assimilation of digested food and egestion of waste material. A number of organs such as m o u t h oesophagus, stomach, duodenum intestines, liver, pancreas, gall bladder and anus t o g e t h e r form an organ system (Digestive system) of human body. Now we will learn about the journey of food in human digestive system, starting from mouth. Human Digestive System: Organs of Human Digestive System: As seen in the diagram, mouth is the first organ of the digestive system. It contains saliva that keeps the mouth moist and also helps in digestion of food. A healthy human make 1 litres of saliva in 24 Hours. CLASS 7 WWW.SCHOLAR-MINDS.COM 11 ACTIVITY 1: Take a morsel of chapatti and chew it for some time. You will notice that the chewed semi liquid food in your mouth starts tasting sweet. Saliva contains juices which convert starch (wheat) into simple sugars. Change of taste in chapatti is due to the breakdown of starch into sugars. Change of taste of chapatti into sugars after chewing proves that saliva present in our mouth helps in the digestion of food. Can you now conclude that digestion of food starts in the mouth itself? Mouth has salivary glands, teeth and tongue. Salivary glands secrete watery liquid called saliva. Starch and Sugars are different typed of carbohydrates. ACTIVITY 2: Aim: Role of saliva in the process of swallowing of food. Apparatus: 50ml beaker, 2 test tubes of 1cm diameter, bread pieces, water. Procedure: Soak 1 piece of bread (3 cms) in 5ml water in a beaker. CLASS 7 WWW.SCHOLAR-MINDS.COM 12 1. Take another piece of bread (same size as above) 2. Stir the contents in the beaker with a glass rod, till it becomes a pulp. 3. Now take 2 test tubes, A and B. 4. Transfer contents of beaker into test tube A. 5. Transfer the piece of bread into test tube B. Observations: In test tube (A) the soaked bread could just flow easily whereas in test tube (B) it could not m o v e in the test tube. Conclusion: Bread made into pulp could be transferred into the test tube easily showing that food needs to be converted into pulp to help swallowing. We know that teeth and tongue help us in biting, chewing and movement of food in the mouth. It helps in converting food into a pulp. It also converts carbohydrates of food into simple sugars. The process of chewing food while it gets mixed with saliva is called mastication. ACTIVITY 4: Survey Select 5 students / friends / neighbours / relatives from following age groups 6-7 yrs. 10-11 yrs. 15-16 yrs. Find out the total number of teeth each one has and record it. CLASS 7 WWW.SCHOLAR-MINDS.COM 13 Do the number of teeth vary in children of different age groups? Milk teeth grow during infancy they fall off at the age between 6-8 yrs. and are replaced by a new set called permanent set. Have you experienced or heard of a tooth ache? Do you know that it could be due to tooth decay? Can you find out the reasons for the same? TONGUE: The tongue is a fleshy, muscular organ attached at the back of the mouth, which performs the following functions: 1. Tasting food 2. Mixing food with saliva CLASS Class VII 7 WWW.SCHOLAR-MINDS.COM WWW.SCHOLAR-MINDS.COM 14 19 3. Swallowing food What happens when we talk or laugh while eating? The air that enters through the nostril goes into the wind pipe. The food pipe is located adjacent to the wind pipe. But inside the throat, air and food share a common opening. The food is prevented from entering wind pipe with help of a flap - like valve which closes the passage of the wind pipe and guides the food into the food pipe while swallowing. By chance if the food goes into the wind pipe we feel choked. OESOPHAGUS: It is a long tube about 30 cm in length commonly called as food pipe. It connects the mouth cavity with the stomach. It acts as a passage for food from mouth to stomach. The food moves in it due to alternate contraction and expansion of muscles, this process is known as Peristalsis. Do you know that vomiting is a process of reverse peristalsis due to which the food is pushed in the opposite direction? STOMACH: Stomach is a flattened U-shaped elastic bag which has a thick wall. It is the widest part of the digestive system. It is connected to the food pipe at one end and to the small intestine on the other end. The gland present on the inner wall of the stomach secretes: CLASS 7 WWW.SCHOLAR-MINDS.COM 15 1. Mucous 2. Hydrochloric Acid 3. Digestive Juices Mucous protects the lining of the stomach. Hydrochloric acid plays a very important role in killing many bacteria that make their way into our body along with food that we eat. It also maintains a n acidic medium which is important for the action of digestive juices in the stomach. Digestive juices break down proteins into simpler substances. The Small Intestine: The next part of the digestive system is the small intestine. It is the longest part of the digestive system. It is about 7.5 meters long and highly coiled. It plays an important role in the digestion of all kinds of food in our body. The small intestine is designed to extract all nutrients before it enters the large intestine. The small intestine in human is long and narrow. Its length is 7.5 mtrs approximately. It digests (breaks down) proteins, fats and carbohydrates. It receives digestive juices from t h e liver, pancreas and its own inner walls. The liver is situated on the right side of the abdomen. It is the largest gland in our body. It secrets bile juice, which is stored in a sac called gall bladder. Bile plays an important role i n digestion of fats. The Pancreas is a large leaf like, cream coloured structure located just below the stomach. The pancreas secretes pancreatic juice that breaks down fats, carbohydrates and proteins into simpler forms. The partly digested food reaches the small intestine, where the intestinal juice completes digestion of all components of the food. Here carbohydrates are broken down to glucose, proteins break down into amino acids, and fats into fatty acids and glycerol. How does this digested food reach in the cells of our body? In the lower part of the small intestine, its inner wall has thousands of folds called VILLI, which look like fingers. Because CLASS 7 WWW.SCHOLAR-MINDS.COM 16 of the folds, the inner surface has a much larger surface area than the outer walls. This provides a very large surface area for ABSORPTION of food. Absorption and Assimilation: What is Absorption? The digested food passes into the blood vessels in the walls of small intestine. Each villus has a network of thin and small blood vessels close to its surface. The villi absorb digested food and transport them via these blood vessels to different organs of the body. These organs utilize digested substances to build proteins or fats as required by the body. This process is called Assimilation. In the presence of oxygen, glucose breaks into CO2 and water to release energy for work. Large Intestine: The undigested and unabsorbed remains of the food pass into the large intestine. The large intestine is so called because of its wider diameter compared to the small intestine. The tube is shorter and is about 1.5 meters long. It absorbs water and some salts from the undigested food and collects the rest of the waste in the rectum. This waste is in the form of a semi-solid called faeces. This faecal matter is removed through the anus from time to time by a process called egestion. CLASS 7 WWW.SCHOLAR-MINDS.COM 17 WORKSHEET 1: Worksheet 2: Following is a list of mode of feeding in different animals. Write down the names of animals against the different modes. Mode of feeding Scraping Capturing Sucking Siphoning Swallowing Chewing CLASS 7 Names of animals WWW.SCHOLAR-MINDS.COM 18 NUTRITION IN HUMAN: We can summarize various steps in the process of nutrition. These are as follows: Ingestion: Intake of food Digestion: The breakdown of food taken in. Absorption: Digested food is absorbed by the small intestinal wall. Assimilation: Food absorbed by small intestine is assimilated by cell components through blood circulation. Egestion: Excretion of undigested food. Digestion in Grass eating animals: You must have seen that animals such as cow chew the food leisurely, by taking back food from their stomach into their mouth. The stomach of cud chewing animals like cow consists of 4 parts 1) Rumen 2) Reticulum 3) Omasum and 4) Abomasum When a cow swallows a mouthful of grass, it is partially chewed and mixed with saliva to form a ball like structure known as bolus before being swallowed and passed down the oesophagus into the stomach. When these animals are grazing, they tend to swallow their food quickly, with only minimal mastication. When the animal is resting after grazing, it regurgitates (bring back into their mouth) this p a r t i a l l y chewed food, re-chews it, and then swallows it again. This process is known as chewing the cud, or rumination and these animals are known as ruminant animals. Depending on the amount of fibre in their food, cattle may spend between 3 6 hours per day chewing their cud. CLASS 7 WWW.SCHOLAR-MINDS.COM 19 Ruminants differ from other animals like humans in the following important ways: a. They have no upper canine teeth, or incisors, and have long, thick and rough tongues. b. They ruminate, by chewing the cud, the food particle size will be reduced, and saliva will be mixed with the food. c. The ruminant digestive system includes a fermentation chamber, called the rumen. The rumen contains micro-organisms which help in digestion of grass. Note: 1. Human stomach has only one chamber. They cannot digest cellulose. 2. Plant cell wall is made up of cellulose. Microorganisms present in the rumen help to digest this cellulose. Feeding and Digestion in Amoeba: Amoeba is a microscopic single-celled organism found in pond water. Amoeba has a cell membrane, a rounded, dense nucleus and much small bubble like vacuoles in its cytoplasm. It constantly changes its shape and position. It pushes out one, or more finger like projections, these are called false feet or pseudopodia for movement and capture of food. Amoeba feeds on some microscopic organisms. When it sense food, it pushes out pseudopodia around the food particle and engulfs it. The food gets trapped in a food vacuole. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. Gradually the digested food is absorbed. The absorbed substances are used for growth, maintenance and multiplication of amoeba. The undigested residue of the food is expelled outside by the vacuole. We can conclude that the basic process of digestion of food and release of energy is the same in all animals. THE END CLASS 7 WWW.SCHOLAR-MINDS.COM 20 SCIENCE LAB EXPERIMENTS a. Aim: To test the presence of starch in a leaf. Procedure: Half fill a beaker with water and boil the water. Place the leaf in boiling water for one or two minutes. This stops chemical reactions. Put the leaf into a boiling tube and pour enough ethanol to cover the leaf. Place the boiling tube into the beaker of boiling water. A water bath is used to prevent accidents that may arise from alcohol (being inflammable). Remove the flame when the ethanol boils. Re-introduce the flame when the ethanol stops boiling. Repeat until the leaf is decolorized. (The green colour gets totally removed.) Re-introduce the flame when the ethanol stops boiling. Repeat until the leaf is decolorized. (The green colour gets totally removed.) When the chlorophyll has been removed (the leaf looks white) remove the leaf from ethanol (the leaf will be brittle). Put the leaf in a petridish having water to soften the leaf and pour two four drops of iodine onto the surface of the leaf. The appearance of blue black colour indicates the presence of starch. B. Aim: To show that light is necessary for Photosynthesis. Materials required: Well watered potted plant, dark paper, scissors/knife, pins. Steps: 1) Fix the paper on one of the leaves as shown in the diagram. 2) This experimental setup is exposed to sunlight for 2-6 hours. 3) The paper is removed and the leaf is tested for starch. CLASS 7 WWW.SCHOLAR-MINDS.COM 21 Conclusion: Starch is produced only in areas that received light, showing that light is necessary for photosynthesis. THE END CLASS 7 WWW.SCHOLAR-MINDS.COM 22 Level - Fundamental Euphoric Science ( Nutrition in plants and animals ) 1. 2. 3. 4. 5. 6. Plants prepare their food by the process of a. Respiration b. Photosynthesis c. Transpiration d. All of these. The organism that can prepare their own food are called a. Heterotrophs b. Consumers c. Decomposers d. Autotrophs Which of the following is not required by plant for food synthesis? a. Water b. Oxygen c. Carbon dioxide d. Chlorophyll Which one is an insectivorous plant? a. Banyan tree b. Cuscuta c. Pitcher plant d. Neem plant Match the following. Column A Column B a. Autotrophs i. Tiger b. Heterotrophs ii. Mushroom c. Carnivores iii. Cuscuta d. Saprophytes iv. Green plants e. Parasite v. Animals Fill in the blanks a. Green plants are called -----------------, since they synthesize their own food. b. Oxygen is released by plants during ------------------. c. -------------------- live on dead and decaying animals. d. -------------------- is the green coloured pigments present in leaves. e. The food synthesized by the plants is stored as -------------------. 7. What is photosynthesis? 8. Distinguished between parasite and saprophytes. CLASS 7 WWW.SCHOLAR-MINDS.COM 23 9. What are insectivorous plants? Give two examples. 10. Observe the diagrams of organisms given below. Name them and write their category. SOLUTION: 1. 2. 3. 4. 5. 6. 7. b d b c (a) (iv), (b) (v), (c) (i), (d) (ii), (e) (iv). (a) Autotrophs (b) photosynthesis (c) saprophytes (d) chlorophylls(e) starch The process by which green plants synthesis their food using sunlight, carbohydrates, water and chlorophyll is called photosynthesis. 8. Those organisms that obtain their food from other organism by harming them are called parasite. For example-Cuscuta, lice, mosquito. Those organisms that obtain food from dead and decaying materials are called saprophytes. For example- bacteria and fungi. 9. Those plants that eat insects by trapping them are called insectivorous plants. They obtain protein from insects. For example- Pitcher plants and Drosophila. 10. (A) Name- Mushroom. Category - Saprophytes. (B) Name Pitcher plant. Category Insectivores. (C) Name Cuscuta. Category Parasites. CLASS 7 WWW.SCHOLAR-MINDS.COM 24 WORKSHEET 2 1. In the process of photosynthesis, the gas given out by green leaves is a. Oxygen b. Carbon dioxide c. Nitrogen d. Ozone 2. To test the presence of starch by iodine, the green leaf is first boiled in alcohol to a. Dissolve chlorophyll b. Remove starch c. Make the leaf soft d. Make the leaf transparent 3. Which of the following is an insectivorous plant? a. Cuscuta b. Croton c. Nepenthes d. Lichen 4. Plant eating animals are called a. Omnivorous b. Carnivorous c. Herbivorous d. Insectivorous 5. Match the following: Column A Column B a. Exchange of gases i. Rhizobium b. Nitrogen ii. Chlorophyll c. Autotrophs iii. Stomata d. Omnivores iv. Green plants e. Photosynthesis v. Bear 6. Write T for true and F for false statements. a. Green plants prepare their food hence they are Autotrophs. b. Carbon dioxide gas is released in the process of photosynthesis. c. Carnivores are flesh eating animals. d. Minute pores on the leaf surface are called stomata. e. Cuscuta is an insectivorous plant. `7. What is the mode of nutrition in plants? 8. What is symbiotic relationship? How it benefits the organisms? 9. Why green leaf is boiled in alcohol before testing it for starch. CLASS 7 WWW.SCHOLAR-MINDS.COM 25 10. Rearrange the letters to find out the words related to plant nutrition. a. ROPHYLCHLO b. UNLISUNHGT c. TERAW d. TOSAMTA SOLUTION: 1. 2. 3. 4. 5. 6. 7. a a c d (a) (iii), (b) (i), (c) (iv), (d) (v), (e) (ii). (a) T (b) F(c) T (d) T (e) F. The mode of nutrition in plants is autotrophic. Plants prepare their food by the process of photosynthesis using inorganic substance. 8. It is the relationship between two organisms in which both organisms get benefited from each other. Symbiotic relationship between algae and fungi is called lichen. 9. Green leaf is boiled in alcohols for testing the starch to dissolve the chlorophyll present in the leaves. After boiling in alcohols leaf will lose its green colour. 10. (a) CHLOROPHYLL (b) SUNLIGHT (c) WATER (d) STOMATA CLASS 7 WWW.SCHOLAR-MINDS.COM 26 WORKSHEET 3 1. Green pigments present in the leaves are called a. Leucoplasts b. Chloroplasts c. Chromoplast d. Amphiplast 2. Which one is saprophytic organism? a. Neem plant b. Mushroom c. Cuscuta d. Pitcher plant. 3. Insectivorous plants are found mostly in areas which are a. Dry and sandy b. Wet and marshy c. Nitrogen deficient d. Nitrogen rich 4. Exchange of gases in leaves takes place through a. Stomata b. Lenticels c. Epidermis d. Guard cells 5. Match the following Column A Column B a. Herbivores i. Amarbel b. Carnivores ii. Yeast c. Omnivores iii. Cow d. Saprophytes iv. Lion e. Parasite v. Cat 6. Fill the blanks with suitable words. a. During photosynthesis, solar energy is trapped by the pigment called -----------. b. -------------- is the ultimate source of energy. c. Gas released during photosynthesis is --------------------. d. Plant eating animals are called ----------------. e. Minute pores on leaf surface for exchange of gases are known as --------------. 7. What are Heterotrophs? Give two examples. 8. What are nutrients? Name main nutrients. 9. Why is sun said to be ultimate source of energy? 10. Name the following. CLASS 7 WWW.SCHOLAR-MINDS.COM 27 a. A parasitic plant which is devoid of leaves, having yellow, slender tubular stem. b. A solution used to test the presence of carbohydrates. c. A plant that has both autotrophic and heterotrophic nutrition. d. The by which organism obtain energy from the digested food. SOLUTION: 1. b 2. b 3. c 4. a 5. (a) (iii), (b) (iv), (c) (v), (d) (ii), (e) (i). 6. (a) Chlorophyll (b) Sun(c) Oxygen (d) Herbivores (e) Stomata. 7. The living organisms that obtain their food directly or indirectly from plants are called Heterotrophs. It includes all animals, human, dog and horse. 8. The components of food that provides us energy to work, to grow and gives us resistance against disease are called nutrients. Main nutrients are carbohydrates, fats, proteins, vitamins and minerals, 9. Sun is the ultimate source of energy as all organisms obtain their food from plants and plants obtain energy from sun during photosynthesis. The energy present in coal and petroleum are also from sun. 10. (a) Cuscuta (b) Iodine solution (c) Pitcher plant (d) Respiration. CLASS 7 WWW.SCHOLAR-MINDS.COM 28 WORKSHEET 4 1. What is the mode of nutrition in animals? a. Heterotrophic b. Autotrophic c. Symbiotic d. All of these. 2. Which of the following is the longest part of the digestive system? a. Large intestine b. Small intestine c. Oesophagus d. Rectum 3. Bile juice secreted by the liver plays an important role in the digestion of a. Protein b. Carbohydrates c. Cellulose d. Fats 4. Finger-like projection called villi are found in the inner wall of a. Small intestine b. Large intestine c. Rectum d. Pharynx 5. Match the following Column A Column B a. Liver i. Acid release b. Large intestine ii. Release of faecal matter c. Rectum iii. Absorption of digested food d. Stomach iv. Bile release e. Villi v. Absorption of water 6. Fill in the blanks. a. Saliva is secreted in the mouth by ----------------. b. Largest gland in human body is -----------------. c. Tongue help in --------------- and -----------. d. Insulin is released by -----------------. e. HCl is released by ---------------- in the stomach. 7. What is mastication? 8. What are enzymes? Give one example. 9. What is digestion? Why it is important? 10. Name the enzyme released from the following glands in human digestive system. a. Salivary glands b. Gastric glands c. Pancreas d. Liver SOLUTION: 1. a 2. b 3. d CLASS 7 WWW.SCHOLAR-MINDS.COM 29 4. 5. 6. 7. a (a) (iv), (b) (v), (c) (ii), (d) (i), (e) (iii). (a) Salivary glands (b) Liver(c) Chewing, mixing (d) Pancreas (e) Gastric gland. The process of chewing of food is called mastication. In this process, saliva is mixed with food. 8. Enzymes are bio-catalyst that helps in digestion of food. They are released from the endocrine glands present in different parts of digestive system. For example pepsin is released from gastric gland help in digestion of protein. 9. The mechanism of breaking down complex organic foods into simpler form by the action of enzyme is called digestion. It is essential for utilization of food components to obtain energy and maintenance of body. 10. Enzyme released from a. Salivary glands Salivary amylase. b. Gastric glands - pepsin c. Pancreas- pancreatic amylase, lipase and trypsin. d. Liver Bile salts. CLASS 7 WWW.SCHOLAR-MINDS.COM 30 WORKSHEET 5 1. Amoeba capture food with the help of a. Tentacles b. Villi c. Pseudopodia d. Food cup 2. Canines are well developed in a. Human beings b. Cattle c. Dogs d. Elephants 3. Which of the following is a dual gland? a. Pancreas b. Liver c. Gastric gland d. Salivary gland 4. Enzymes are a. Carbohydrates b. Acids c. Bio-catalyst d. Bases 5. Match the following Column A Column B a. Incisor i. Grinding and crushing food b. Canine ii. Biting the food c. Molar iii. Tearing food d. Tongue iv. Release enzyme e. Salivary gland v. Mixing of food 6. Write T for true and F for false statement. a. The large intestine absorbs water and minerals. b. Pancreas is the largest gland in our body. c. Amoeba ingests food with the help of pseudopodia. d. Villi help in digestion of food. e. Animals can digest cellulose. 7. Where is bile produced? Which component of the food does it help to digest? 8. What are villi? Write its function? 9. What are ruminants? How do they digest cellulose? 10. Provide single term for the following: a. The organ which stores bile. b. Finger-like outgrowth in the small intestine. c. The part of amoeba which help in capturing food. d. The longest part of alimentary canal. e. The part which feels the taste of different food items. CLASS 7 WWW.SCHOLAR-MINDS.COM 31 SOLUTION: 1. 2. 3. 4. 5. 6. c c a c (a) (ii), (b) (iii), (c) (i), (d) (v), (e) (iv). 6. (a) T (b) F(c) T (d) F (e) F. Bile is produced in liver. Bile contains bile juices which emulsify the fats into smaller fat globules to make it easier for digestion of fat. 7. Villi are small finger-like projection in the small intestine. It increases the surface area for absorption of digested food. Rich supply of blood help in transport of food to all parts of the body. 8. The animals having four chambered stomach are called chewing animals or ruminants animals. For example cow, which always seems to chew something throughout the day. 9. Single words a. Gall bladder. b. Villi. c. Pseudopodia d. Small intestine e. Tongue. CLASS 7 WWW.SCHOLAR-MINDS.COM 32 WORKSHEET 6 1. A substance which kills bacteria in stomach a. Water b. Hydrochloric acid c. Sulphuric acid d. Citric acid 2. Animals that chew cud are called a. Herbivores b. Omnivores c. Ruminant d. Grass eating 3. Total number of canines teeth in adult human beings are a. 2 b. 4 c. 6 d. 8 4. Gastric juice contain enzyme a. Lipase b. Amylase c. Cellulase d. Pepsin 5. Match the following Column A Column B a. Mastication i. Gall bladder b. Ruminant ii. Pseudopodia c. Ptyalin iii. Teeth d. Ingestion in amoeba iv. Cellulose digesting e. Bile storing organ v. Saliva 6. What Oral Rehydration Solution? 7. Mention the important functions of pancreas. 8. Fill in the blanks a. Saliva is secreted in mouth by --------------------. b. . --------------------- is produced by liver. c. Food is pushed down into the stomach by ---------------. d. Amoeba digest its food in the ----------------. e. Digestion of starch starts in ----------------------. 9. What are ruminants? Name the four compartments of their stomach? 10. What are ruminants? Name the four compartments of their stomach? SOLUTION: 1. 2. 3. 4. 5. 6. 7. CLASS 7 b c b d (a) (iii), (b) (iv), (c) (v), (d) (ii), (e) (i). (a) Salivary glands (b) Bile juice(c) peristaltic movement (d) food vacuole (e) mouth. Gastric juice is released by gastric glands present in wall of stomach. It contains HCl, pepsin, WWW.SCHOLAR-MINDS.COM 33 and mucus that help in digestion of food. Grass eating animals are called ruminants. They can digest cellulose. The stomach of these animals is four chambered. 9. ORS is boiled but cooled water with a pinch of salt and some sugar dissolved in it. Excess loss of water from the body can be maintained by giving ORS solution frequently. 10. Pancreas is a dual gland that releases hormone as well as enzyme. The main hormone released by pancreas is insulin that control sugar level in blood. The enzyme released by pancreas includes amylase, trypsin, lipase. 8. THE END CLASS 7 WWW.SCHOLAR-MINDS.COM 34 Level - Accelerator Euphoric Science (Nutrition in Plants and Animals) 1. Green plants, algae and some bacteria can produce their own food by the process of _________________ a. Photosynthesis b. Chlorophyll c. Heterotrophic d. All of these 2. The organisms who make their own food are called _________ a. Heterotrophs b. Autotrophs c. Parasites d. All of these 3. Mildew growing on plant is an example of _______ nutrition a. Autotrophic b. Heterotrophic c. Parasitic d. Saprophytic 4. Which one of the following is a saprophyte? a. Mushroom b. Yeast c. Bread mould d. All of these 5. Which of the following obtain its food by parasitic mode of nutrition? a. Algae b. Bread mould c. Dodder Plant d. All of these 6. Which one of the following carry food from mouth to stomach? a. Oesophagus b. Pancreas c. Gall Bladder d. Large Intestine 7. Amoeba intakes its food with the help of a. Tentacles b. Cilia c. Pseudopodia d. None of these 8. The process which is involved in utilizing the digested food by cells is a. Egestion b. Digestion c. Assimilation d. Absorption 9. In which of the following parts of digestive system most of the water from the undigested food is absorbed? a. Oesophagus b. Stomach c. Small Intestine CLASS 7 WWW.SCHOLAR-MINDS.COM 35 d. Large Intestine 10. The process of removing the undigested food out of the body is called a. Egestion b. Digestion c. Assimilation D. Absorption 11. On Saturday, Sumit after having his lunch, forgot his lunch box in the school. When he opened it on Monday, he found that it had some blackish brown, cottony stuff in it. Which of the following organisms can it be most likely be? a. Mushroom b. Amoeba c. Rhizopus d. Either A or C 12. Most crops require a lot of nitrogen to synthesize the proteins. The bacterium Rhizobium helps some of the crops to get nitrogen. Which of the following statements is incorrect for Rhizobium? a. It converts atmospheric nitrogen into soluble form that the plants can absorb b. It can make its own food c. It lives in the roots of leguminous plants like gram, peas, moong etc d. Leguminous plants provide food and shelter to Rhizobium. THE END CLASS 7 WWW.SCHOLAR-MINDS.COM 36 Level Olympiad Euphoric Science (Nutrition in Plants and Animals) 1. Priyanka took a de-starched plant and setup an experiment as shown in the figure. She left the plant in sunlight for few hours and then tested the leaves X and Y for starch. Leaf X did not give starch test while leaf Y showed presence of starch. What is proved by this? a. Chlorophyll is necessary for photosynthesis. b. Carbon dioxide is necessary for photosynthesis c. Light is necessary for photosynthesis. d. Oxygen is given out during photosynthesis. 2. Hydrochloric acid secreted in the stomach is strong enough to kill bacteria that enter along with food, then, how inner lining of the stomach is protected from such a corrosive action of hydrochloric acid? a. Inner lining of stomach is thick enough to prevent corrosive action of HCl b. Inner lining of stomach secretes mucus which forms a protective layer over it. c. The glands in the stomach secrete some bases that neutralize the effect of HCl. d. All of the above. 3. The given list shows the five steps needed to do a starch leaf test but in random order 1. Pluck a leaf from the plant 2. Leave a potted plant out in the sun for a few hour 3. Boil the leaf in the alcohol 4. Boil the leaf in water. 5. Wash the leaf and then add a few drops of iodine solution over it. a. 1,2,3,4,5 b. 1,2,4,3,5 c. 2,1,5,4,3 d. 2,1,4,3,5 4. Monu is a poor farmer. He cannot spend money on buying fertilizers. What should he do to increase fertility of his farmland a. He should grow eucalyptus trees in his field b. He should water his field more frequently. c. He should grow pea plants in his field d. He should grow mustard plants in his field. 5. The given figure shows different types of teeth. Which of these is used for piercing and tearing of food? a. X b. W c. Both Wand Y d. Both Y and Z 6. The given figure shows the movement of food through the oesophagus. This movement is aided by the muscles of the oesophagus in a wave like action called a. Diapededsis b. Peristalsis c. Rumination CLASS 7 WWW.SCHOLAR-MINDS.COM 37 d. Muscularisation 7. Refer the given figure . It illustrates a. Autotrophic nutrition b. Heterotrophic nutrition c. Parasitic nutrition d. Symbiotic Nutrition 8. The given figure shows the human digestive system. Which of the labelled parts secretes enzyme pepsis. a. P b. R c. S d. Q 9. Read the given statements. (i) Paramecium has stiff hair like structures called ____________ all over its body, which are used for ______________ (ii) Hydra has a number of ___________ around its mouth that entangle small aquatic animals and kill them with their______________cells (iii) Frog uses its long,sticky ______________ to catch insects. (iv) Mosquito sucks up the blood of animals with its________________ Select the option which correctly fills the blanks in any of these statements a. (ii) Cilia, Absorptive; (iii) Hand b. (i) Tentacles ,Ingestion; (iv) Feeding tube c. (i) Cilia,Ingestion; (ii) Tentacles ,Stinging d. (iii) Tongue; (iv) Psedopodia 10. Read the given paragraph. The a secretes bile juice which is stored in the b .The bile breaks up c Into tiny droplets that can be digested and absorbed more easily. The digestive juices then act on these tiny droplets to form simpler compounds known as d and e . Select the option which correctly completes the above paragraph. a b c d e A Pancreas Spleen Proteins Amino acids Glycerol B Liver Gall bladder Starch Fructose Maltose C Liver Gall bladder Fats Fatty acids Glycerol D Small Spleen Fats Amino acids Fatty acids intestine 11. Match column 1 with column 2 and select the correct option from the codes given below: Column 1 Column 2 (a) chlorophyll (i) rhizobium (b) symbiosis (ii) starch (c) insectivorous plants (iii) lichen (d) nitrogen fixing bacteria (iv) mistletoe (e) partial parasite (v) pitcher plant A B C D CLASS 7 (a) (i) ( iii) (ii) (v) (b) (iv) (v) (iii) (iv) (c) (iii) (ii) (v) (i) (d) (ii) (i) (i) (ii) (e) (v) (iv) (iv) (iii) WWW.SCHOLAR-MINDS.COM 38 12. Read the given statements and select the correct option. Statement 1: chewing breaks down the food into small pieces and aids in digestion. Statement 2: chewing increases the surface area of the food for the saliva to act upon. A. Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. B. Both statements are true and statement 2 is not the correct explanation of statement 1. C. Statement 1 is true but statement 2 is false. D. Both statements 1 and 2 are false. 13. The steps of the digestive process are listed below but not in correct order. (i) Water and vitamin absorption begins. (ii) Food is liquefied; breakdown of proteins begins. (iii) Food is moistened; breakdown of starch begins. Proteins, carbohydrates and fats breakdown; nutrients are absorbed in the blood (iv) stream. Select the option that gives the correct order of these events as food passes through the digestive tract. A. (ii), (iv), (i), (iii) B. (iv), (ii), (iii),(i) C. (i), (iii), (ii), (iv) D. (iii), (ii), (iv), (i) THE END CLASS 7 WWW.SCHOLAR-MINDS.COM 39

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