Science Class VII PDF

Science Class VII Department of Curriculum and Professional Development Ministry of Education Thimphu Published by Department of Curriculum and Professional Development (DCPD) Provisional edition 2013 Provisional edition 2013 First edition 2017...

Science Class VII Department of Curriculum and Professional Development Ministry of Education Thimphu Published by Department of Curriculum and Professional Development (DCPD) Provisional edition 2013 Provisional edition 2013 First edition 2017 Second edition 2020 Reprint 2022 Copyright © 2022 Department of Curriculum and Professional Development (DCPD), MoE, Thimphu. Acknowledgment The Royal Education Council would like to thank all the science faculty members of the Colleges of Education, Paro and Samtse and teachers from different schools for their valuable contributions towards the development of this book. Our sincere gratitude goes to Ministry of Education, Royal Society for Protection of Nature, Ministry of Agriculture, Ministry of Health, Ministry of Economic Affairs, and other relevant agencies for their unfailing support, starting from the development of the Science Curriculum Framework to the production of science textbooks and manuals. The curriculum revision was possible with the generous financial and technical support rendered by relevant stake holders. The National Environment Commission in integration of Sustainable Waste Management from ‘Ecology Note: Towards a Clean, Green, and Beautiful Bhutan’. The United Nations Population Fund (UNFPA) through Ministry of Education in inclusion of components of Comprehensive Sexuality Education in strengthening life skill education for children. Our sincere courtesy to all the source of pictures that are used in this book Advisors Sangay Zam, Secretary, Ministry of Education, Thimphu Tshewang Tandin, Director General, Department of Adult and Higher Education, Ministry of Education, Thimphu Kesang C Dorji, Director, Department of Curriculum and Research Division, Ministry of Education, Paro Kinga Dakpa, Director General, Royal Education Council, Paro Wangpo Tenzin, Dean, Royal Education Council, Paro Coordination Wangchuk, Royal Education Council, Paro Proof Reading Gopilal Acharya, Free Lance Editor, Thimphu Amber Kumar Rai, Curriculum Officer, Royal Education Council, Paro Sharda Rai, Subject Specialist, Bhutan Council for School Examination and Assessment, Thimphu Art Work and Layout Surjay Lepcha, Curriculum Officer, Royal Education Council, Paro Sangay Tshering, Teacher, Drugyel HSS, Paro. No part of this book shall be used without written permission from Royal Education Council, other than for educational purposes. ISBN 978-99936-0-416-7  Foreword Today, science is an indispensable discipline of learning that shapes the lives of humankind and their wellbeing. The enduring engagement of people in the scientific world of exploration, inquiry and investigation has culminated in the addition of an ever-growing repository of scientific knowledge and milestones. Through the time, how science works and affects the world has been influencing the way we view and deal with the subject. Unfortunately, many a times, the subject is seen as very complex and difficult, hard to comprehend and demanding to learn, thereby posing challenges in our effort in instilling scientific beliefs and attitudes in young learners. Such generalisation has influenced the learners to shy away from the experiential learning and the scientific endeavour in favour of a discipline that is perceived to be easier. Therefore, it is time that concerted efforts are pursued in making learning of science a way of igniting the fire of curiosity and investigation in the minds of learners. Towards making education meaningful and relevant for students, it is imperative to link the scientific concepts to the real world through rigorous engagement of learners in the scientific processes of observation, inquiry, investigation, experimentation and generalisation. The timely revision of science textbooks is an attempt to align learning outcomes with the emerging global view of science and educational philosophies, accentuate the development of scientific skills of doing science, and foster the scientific temper and literacy in young minds. However, the endeavour in science education in our context emanates from the national, social, cultural and religious belief system imperative to nurturing nationally rooted and globally competent citizens who can productively contribute to the nation building initiatives and development of a dynamic global society. Therefore, it is our sincere hope that the science curriculum provides a limitless avenue for every learner as a young scientist to explore continuously and engage in doing science. The meaningful participation is crucial in the development of transversal competencies of critical thinking, creativity, communication and collaboration along with other essential life skills fundamental to succeed and excel in the 21st century world as productive and socially responsible individuals. I would like to wish all our teachers and students, a fulfilling social and academic engagement and experiential experiences through enduring and enterprising learning and doing science as part of every learner’s life. Tashi Delek Kinga Dakpa Director General  Contents Foreword iii Introduction vii UNIT I : Life Processes 1. Cell 1 2. Human as Organism 14 3. Green Plant 50 4. Living Things and their Environment 73 UNIT II : Materials and their Properties 5. Classifying Material 88 6. Patterns in Chemistry 108 7. Material and Change 129 8. Mixture 142 UNIT III : Physical Processes 9. Work and Energy 150 10. Force and Motion 164 11. Electricity and Magnetism 197 12. Light and Sound 221 13. The Earth and Beyond 325 Annexture Annexure A 337 Annexure B 350 Annexure C 361 vi  Introduction Science as a body of knowledge allows an individual to explore, create, and organize ideas in the form of testable explanations and predictions that ultimately enable the discovery of new knowledge. Science has thus far played an important role in helping humankind to best understand the universe, make the best use of natural resources, and advances accordingly. The importance of Science has been revealed through the way science and scien- tific knowledge has shaped the lives of human since the time immemorial. The advancement of a human world was possible due to the influence of science as al- most all the activities, from sowing a seed to building a rocket involves scientif- ic knowledge. Thus, science has become an indispensable discipline for the sur- vival and advancement of humankind. Being conscious of the role science has played in shaping the lives of humankind and the power it holds for further ad- vancement, catching up with the new and possible discoveries in the field of sci- ence are very important and urgent to progress along with the world around us. Nonetheless, the unfounded belief of viewing science as a subject for the elite learner has affected the way we view and deal with the subject. Many times, the subject is seen as very complex and difficult, tough to comprehend, and demanding to make sense out of associated concepts. Such generalization has influenced the learners to shy away from it in favour of a discipline that is perceived to be easier. This trend has challenged the effort of instilling scientific beliefs and attitudes in young learners. It has, therefore, called for a concerted effort to make learning of science a way of igniting the fire of curiosity in the minds of learners. Such a move is possible only when all the players collaborate to provide and use the right tools, forum, oppor- tunities and instructions supported by consistent follow-up and monitoring while teaching and learning science. In essence, dealing with science should foster seeing, using and doing the real things so as to give ‘the feel of real science’ to the learn- ers. It is imperative to link the concept to the real world, for science encompasses the understanding of structure and behaviour of the physical and natural world that can be better understood only through the use of the scientific inquiry process. vii Scientific Process A scientific process is an inquiry approach that involves a systematic understanding of the natural and physical world. It forms the basis of experimentation for scientific knowledge. It is imperative to know the basic scientific process to derive predictions and confirmations from the ideas and information gathered through observation of different phenomena. Thus, it entails asking relevant questions related to observation, testing ideas, and communicating the findings. The scientific process includes: 1. Observation IIt is the fundamental skill that enables learners to view the world objectively and systematically by using all the senses. It consists of gathering information, evidences, and ideas about different phenomena. This facilitates learners to compare, contrast, and generalise ideas about the world around them. These experiences foster inquisitiveness in them. 2. Questioning The competency that involves creative and critical thinking which attempts to link the known with the unknown ideas. It enhances the ability of the learners to put their observations in the form of a question that is clear, concise, and testable. 3. Hypothesis It is an educated guess and possible explanation about the observation and question. Based on the limited evidence as a starting point, learners carry out further investigation. Therefore, the hypothesis is a specific and testable prediction about what may happen in a study. 4. Background information It is the collection of relevant and significant information regarding the topic in order to provide a comprehensive understanding of what has been said on the topic and by whom. Through this step, the learner build-up a story related to the question and hypothesis. 5. Design It is an experimental set-up that allows investigation of the relationship between variables. This allows learners to manipulate the variables and test whether their prediction is accurate. viii  6. Data collection It is the systematic observation, measurement, and recording of information about various phenomena happening in the experimental set-up. It allows learners to gather evidence to answer stated research questions, test hypotheses, and evaluate outcomes. 7. Analysis It is an interpretation of data through the use of analytical and logical reasoning to determine the patterns, relationships, and trends. The learner makes sense out of the information recorded to establish a relationship between variables, based on which results and conclusions are drawn. 8. Conclusion It is the step where the learner makes generalisation of the information based on the data analysis and interpretation. The generalisation may or may not support the hypothesis. This facilitates learners to develop the skills of articulating diverse information to draw a comprehensive conclusion about the phenomena. 9. Sharing This is the final step wherein the learner presents their findings in the form of a final report, display or presentation as asked by the subject teacher. The learners explore and learn to use different forms of communication such as graphic, audio-visual, etc. to share their ideas or findings. Textbook Content The content in this textbook covers topics on Biology, Chemistry, and Physics in equal proportion to promote the learning of concepts in all the three disciplines. The concepts under each topic are made learner-friendly by incorporating various kinds of activities that meaningfully engages both teacher and learners. Essentially, this textbook contains the following learning experience plan. Learning objectives: The list of statements that define what learners are expected to know at the end of each topic or chapter. Activity: This provides information on the aim, the materials required and steps to carry out the activity. It is intended to provide hands-on experience for the learners and test the learned theory or to draw generalization and build concepts. ix Do you know? This is provided as additional information to add to general knowledge in science. This is not for testing. Questions: Where appropriate, the questions are provided to immediately test the concepts learned. This will help learners to test their understanding. Exercise: This is provided to check the understanding of the concepts learned in the chapter. It has different sets of questions to test learning in terms of scientific knowledge, skills, and values and attitudes. Model Question Paper: This is provided at the end of the textbook to help learners familiarize with the type of questions that are expected in the terminal examinations. It provides cues of the range of cognitive level of learnings, skills, the values and attitudes that the science curriculum is expected to achieve. The realization of the curriculum aspirations and intends is determined by the way the curriculum is implemented. So, the use of various strategies that allows learners to explore diverse strategies will help realize the curriculum’s intent besides fostering scientific aptitude and attitude in the learners. The provision of avenues to arouse curiosity will go a long way in fostering intellectual development and enhancement of overall performance. If the right tools and strategies are being used, this science curriculum will provide a limitless avenue for the learners to explore continuously on and beyond the scientific concepts embedded in this book. STEM Unit, CDC Royal Education Council x  Chapter 1 Cell Our surrounding is full of different kinds of living organisms. All living organisms are made up of cells. Generally, cells are so small that they cannot be seen with naked eyes. They can be seen only with the help of a microscope. Some organisms are made up of a single cell while others are made up of many cells. Cells vary in shape and size. Inside a cell, there are several essential structures which carry out different functions. 1. Cell – the building blocks of life Learning Objectives On completion of this topic, you should be able to: describe cell as the building blocks of life. categorise living things into unicellular and multi-cellular organisms. use a compound microscope to observe an animal cell and a plant cell. draw the structure of an animal cell and a plant cell. Just as bricks are the building blocks of a house, cells are the building blocks of a living organism. This means the living organisms are made up of cells. These cells form the structure of an organism and carry out all the functions to keep the organism alive. Our body is also made up of cells which carry out different functions to keep us alive. Therefore, cell is the structural and functional unit of all living organisms. The branch of science that deals with the study of cell is known as cytology. Some organisms are made up of single cell. Such organisms are called unicellular organisms. For example, yeast, Amoeba, Chlamydomonas and bacteria as given in Figure 1.1. 1 Reprint 2022  Chapter 1: Cell (a) Yeast (b) Amoeba (c) Chlamydomonas (d)Bacterium Figure 1.1. Unicellular organisms. Organisms like human ,fish,bird, tree, and insect are made up of many cells. Such organisms are called multicellular organisms as shown in Figure 1.2. (a) Trout (Fish) (b) House fly (insect) (c) Human being (d) Oak (Tree) (e) Sparrow (Bird) Figure 1.2. Multi-cellular organisms. Cell was first discovered in a thin slice of cork by Robert Hooke. He found that the cork was made up of many tiny ‘honey-comb like’ compartments. Later, similar structures were observed in wood and other plants. He named these structures as cells. a. Shape and size of cells Cells vary in shapes and sizes. They are spherical, oval, rectangular, cylindrical or irregular in shape as shown in Figure 1.3. Most of the cells are very small and are seen only with a microscope. However some cells, like bird’s egg is large enough that we can see with our naked eyes. 2 Reprint 2022  Chapter 1: Cell Nerve cell Bone cell Sperm cell Ovum cell Plant cell Figure 1.3. Shapes of different cells. Do You Know? The ovum (female reproductive cell) is the biggest human cell. It is about the size of a dot which can be seen by naked eyes. All other human cells are microscopic. Activity 1.1. Using microscope to observe plant , and animal cell Materials required Precaution Compound microscope, permanent slide of human Do not let the objective lens touch the RBC, permanent slide of glass slide while using the microscope. T.S of monocot stem. Procedure Step 1. Take a clean permanent slide of human RBC. Step 2. Place the slide on stage of microscope with the mount of the specimen over the aperture and clip it. Step 3. Adjust 10X power objective lens to the specimen. Step 4. Open the diaphragm. Step 5. Look through the eye piece and adjust the mirror to reflect light on the slide. 3 Reprint 2022  Chapter 1: Cell Step 6. With the help of coarse adjustment knob, focus the specimen. Adjust the slide if required. Step 7. For precise focusing and clear view, use fine adjustment knob. Step 8. Repeat Step 1 to Step 7 using permanent slide of T.S of monocot stem. Answer the following question. i. Draw what you observe under the microscope in each case. ii. What is the shape of RBC and cell of monocot stem? Activity 1.2. Preparing temporary slide Materials required Precaution Onion, knife/blade, mounting needle, forceps, Handle knife and microscope, glass slide, cover slip, watch glass, blade with care! water, iodine solution, blotting paper, and dropper. Procedure Step 1. Cut the onion bulb into small pieces as shown in Figure 1.4 (a). Step 2. Using the forceps, remove a thin peel from the concave side of onion piece as shown in figure 1.4 (b). Step 3. Place the peel in the watch glass containing a few drops of water. Step 4. Add a few drops of iodine to stain the peel. Step 5. Place a peel on the center of glass slide with the help of forceps as shown in figure 1.4(c). Step 6. Place a cover slip over the peel with the help of a mounting needle as shown in figure 1.4 (d) and (e). Step 7. Make sure that there is no air bubble in between the cover slip and glass slide. Remove the excess fluid with the help of a blotting paper. Step 8. Observe the slide under low power of the microscope. 4 Reprint 2022  Chapter 1: Cell (a) (b) (c) (d) (e) (f) Figure 1.4. Steps for preparing temporary slide. Answer the following questions. i. Draw what you observe under the microscope. ii. What is the shape of the structures that you see in the onion peel? What are they called? iii. Is the onion a unicellular or multi-cellular organism? Give reason to support your answer. Questions 1. Define cell. 2. Why do you observe cell under a microscope? 3. Categorize the given organisms into unicellular and multicellular. (mosquito, mango, paramecium, euglena, hydra) 5 Reprint 2022  Chapter 1: Cell 2. What is inside a cell Learning Objectives On completion of this topic, you should be able to: identify the basic structures of animal, and plant cell. identify the similarities and differences between animal, and plant cell. draw and label the basic structures of animal, and plant cell. make a model of plant and animal cell. You have learned that all organisms are made up of cell. Each cell consists of a number of specialized parts. The three basic parts in a cell are cell membrane, cytoplasm and nucleus. a. Structure of an animal cell An animal cell contains various cell organelles as shown in Figure 1.5. Vacuole Golgi bodies Cell membrane Endoplasmic reticulum Nucleolus Nucleus Nucleoplasm Nuclear membrane Centrosome Cytoplasm Ribosome Mitochondria Figure 1.5. Animal cell. i. Cell membrane (plasma membrane): It is a semi-permeable living membrane that forms the outer most layer in the animal cell. It encloses various cell structures and cytoplasm. ii. Cytoplasm: It is a semi-liquid, colourless and translucent substance. It occupies most part of the cell within the cell membrane. There are various specialized bodies found within the cytoplasm. These bodies are called cell organelles. 6 Reprint 2022  Chapter 1: Cell Some cell organelles are described below. Endoplasmic Reticulum: It is an irregular network of membranes connecting the plasma membrane and the nuclear membrane. Mitochondria: These are spherical, oval or rod shaped organelles with double membrane. Ribosome: It is a small organelle found either scattered in the cytoplasm or attached to the membranes of the endoplasmic reticulum. Golgi bodies: These are very small vesicles of different shapes, and are located near the nucleus. They consist of flattened tubes and round structures. Centrosome: It is a star-like structure located near the nucleus. It is found only in animal cells. Vacuoles: These are large cavities filled with a fluid called cell sap. In animal cells, the vacuoles are usually smaller and fewer than in plant cells. iii. Nucleus: It is an oval shaped organelle present somewhat in the centre of the cytoplasm. It is surrounded by double layered nuclear membrane. Nucleus is filled with a dense semi fluid substance called nucleoplasm. One or two small spherical bodies, called nucleoli (singular nucleolus), lie within the nucleus. http://www.kscience.co.uk/animations/animal_cell.htm 7 Reprint 2022  Chapter 1: Cell b. Structure of a plant cell Plant cells have all the structures that are present in the animal cells except the centrosome. However, they have the following additional structures: Cell wall Ribosome Golgi bodies Cell membrane Nucleus Plastids Endoplasmic reticulum Cytoplasm Vacuole Mitochondria Figure 1.6. Plant cell. i. Cell wall: In plant cell, the cell membrane is surrounded by a rigid structure called cell wall. It is a non-living layer made up of cellulose. ii. Plastid: It is a large organelle surrounded by double membranes. It is of three types based on the type of pigments it contains. Chloroplast: It contains green pigment called chlorophyll. It is found in leaves, stems, and buds. Chromoplast: It contains pigments of various colours that give colours to flowers and fruits. Leucoplast: It is colourless and contains no pigment. It is found in endosperm, tubers, and cotyledons. http://www.kscience.co.uk/animations/plant_cell.htm 8 Reprint 2022  Chapter 1: Cell Activity 1.3. Comparing animal cell and plant cell Open the link and use the simulation to compare plant cell and animal cell. https://sepuplhs.org/high/sgi/teachers/cell_sim.html i. Write their similarities. ii. Write their differences. Activity 1.4. Making models of animal cell and plant cell Use image editing software (MS paint, Inkscape, Edraw, etc.) to design a 2D model of plant cell and animal cell. Present your work to the class. Questions 1. Figure 1.7 shows a plant cell. Figure 1.7. Identify the three basic structures of the cell. 2. Differentiate between cell wall and cell membrane. 3. Draw a labelled diagram of an animal cell. 9 Reprint 2022  Chapter 1: Cell Exercise Fill in the blanks 1. A ………………carry out all the functions to keep an organism alive. 2. Cell was first discovered in tiny compartment in a piece of...................... 3. Irregular network of membranes inside a cell is…………………… 4. Nucleolus is present inside a ………………………….of a cell. 5. The red colour of a rose is due to the presence of ………………… Check whether the following statements are True or False. Correct the false statements. 1. The substance present in the cell wall is protein. 2. Both animal and plant cells have cell membrane. 3. An ant is a unicellular organism. 4. The study of cell is called histology. 5. The colourless plastid present in potato is chromoplast. Match the Following Column A Column B 1. Outer layer of a plant cell A. multicellular 2. Structural and functional unit B. chlorophyll 3. Green colouration in leaves C. cell membrane 4. Paramecium D. cell wall 5. Living, semi permeable membrane E. cell F. unicellular 10 Reprint 2022  Chapter 1: Cell Multiple Choice Questions 1. The examples of multicellular organisms are A. Bacteria, tiger and deer. B. Bacteria, tiger and sugarcane. C. Tiger, Paramecium and sugarcane. D. Tiger, deer and sugarcane. 2. Which is not a part of animal cell? A. Nucleus B. Cell wall C. Ribosomes D. Cell membrane 3. Cells are best seen with A. hand lens. B. naked eye. C. simple microscope. D. compound microscope. 4. Cell sap is found in A. nucleus. B. plastids. C. vacuole. D. cytoplasm. 5. Cells are of various shapes and sizes. The biggest single cell known is the A. amoeba. B. bacteria. C. egg of an ostrich. D. human ovum. 11 Reprint 2022  Chapter 1: Cell Answer the following questions 1. Answer question i and ii based on the information given below. In biology laboratory, Tashi observed a cell under a microscope. While focusing on the cell, his attention was drawn to a tiny star like body close to a large dense spherical body at the centre. He also observed many rod shaped structures scattered inside the cell. (i) Identify the cell organelles observed by A Tashi. (ii) Is it a plant cell or an animal cell? 3. Study the diagram of a cell in Figure 1.8 and answer the following questions. i. In which group of organisms would you find this cell? Give reasons to B support your answer. C ii. Name the parts labelled A, B, C, and D D. 4. Cell is the structural and functional unit Figure 1.8. of living organisms. Explain. 5. Identify the centrosome, ribosome, nucleus, and endoplasmic reticulum in figure 1.9. Figure 1.9. 12 Reprint 2022  Chapter 1: Cell 6. A student is making a temporary slide as shown in Figure 1.10. Mounting needle Cover slip Slide Drop of water Figure 1.10. (i) Why should the student make sure that the edge of the cover slip touches the drop of water before setting the cover slip onto the glass slide? (ii) Why did the student use the cover slip? 13 Reprint 2022  Chapter 2 Human as Organism Human beings are one of the most highly developed and complex organisms amongst all the living organisms. The human body has different types of cells that make different organs and organ systems like the skeletal system, respiratory system, nervous system, and the reproductive system. In order to keep our body healthy, a variety of foods including minerals and vitamins are needed. Good health also depends on physical exercises and personal hygiene. Lack of nutrients and unhygienic conditions can cause various diseases. 1. Food and Nutrients Learning Objectives On completion of this topic, you should be able to: define nutrients and nutrition. identify different types of nutrients and their importance. identify deficiency diseases. carry out food test. All living organisms need food to live and grow. The process of intake of food, and converting it into energy and other vital nutrients which are used by the body is called nutrition. In order to be healthy, we need to take a diet containing all the necessary nutrients in right amount. A nutrient is a particular substance contained in a food. Most of the food contains a mixture of different nutrients. Each nutrient has a role to play in keeping the body healthy. Lack of proper nutrients can cause deficiency diseases. The nutrients in food can be classified into carbohydrates, fats, proteins, minerals and vitamins. 14 Reprint 2022  Chapter 2: Human as Organism a. Carbohydrates Many of us eat rice, maize, potato, fruits, bread, and jam. All these food items contain carbohydrates. They are organic compounds containing carbon, hydrogen and oxygen. They are the main source of energy for all living beings. Food rich in sugar and starch are grouped as carbohydrates. Glucose is the smallest and simplest unit of carbohydrates. Activity 2.1. Which foods contain carbohydrates? Materials required Raw potato, rice flour, maize flour, wheat flour, petri dish, iodine solution, dropper and knife. Procedure Step 1. Take the raw potato and cut it into two halves with the knife. Step 2. Place one half of the potato in a petri dish. Step 3. Using the dropper, add two drops of iodine solution on the cut surface of the potato. Observe what happens? Step 4. Try the similar test with the rice flour, maize flour and wheat flour and record your observations in Table 2.1. Precaution Be careful while using knife. Table 2.1 Carbohydrate Test Food Item Observation Rice flour Wheat flour Maize flour Answer the following questions based on activity 2.1. i. What is the common observation? ii. What conclusion can you draw? 15 Reprint 2022  Chapter 2: Human as Organism b. Fats Fats are made of carbon, hydrogen and oxygen. Compared to carbohydrates, fat contains less proportion of oxygen but more carbon and hydrogen. Fatty acid and glycerol are the smallest units of fats. Fats produces energy for organisms to carry out their metabolic activities. They also protect the body against loss of heat. Butter, cream, egg, seed and nut, dry fruit, cheese, meat, fish, vegetable oil, etc. are some examples of fats. Activity 2.2. Which foods contain fats? Materials required Vegetable oil, walnut, hair oil, butter, paper, dropper and tongs. Procedure Step 1. Put a few drops of vegetable oil on the paper and dry it. Step 2. Hold the paper to the light with the tongs and look through it. Step 3. Try applying rest of the food items on the paper and record your observations in Table 2.2. Table 2.2 Fat Test Food Item Observation Walnut kernel (crushed) Hair oil Butter Answer the following questions based on activity 2.2. i. What is the common observation? ii. What conclusion can you draw? iii. How different are the results with each food item? 16 Reprint 2022  Chapter 2: Human as Organism c. Proteins Proteins are organic compounds containing carbon, hydrogen, oxygen and nitrogen. The simplest unit of protein is amino acid. There are different types of amino acids, which combine together to produce varieties of proteins. Protein helps in growth, repair and replacement of injured parts of the body. Fish, meat, milk, egg, beans, peas are the major sources of protein. We take different types of food to provide us with different nutrients essential for growth and energy. Deficiency of protein, carbohydrates and fats results in Protein Energy Malnutrition Figure 2.1. A child suffering (PEM). Malnutrition is a condition caused due to from Kwashiorkor. unbalanced intake of nutrients. PEM causes two types of malnutrition in children, kwashiorkor and marasmus. Kwashiorkor is a form of malnutrition that occurs in children when there is not enough protein in the diet. This disease is characterised by pot belly, thin legs, and ugly patches on skin, mental retardation, and slow physical growth. A protein rich diet obtained from animals or from soya bean can cure kwashiorkor. Marasmus is a disease in children caused by deficiency of protein, carbohydrate and fats. Children suffering from this disease have loose Figure 2.2. A child suffering folds of skin, very thin arms and legs, slow growth from marasmus of body, and they become lethargic. It can easily be prevented and controlled by taking enough carbohydrates and proteins. 1.http://www.agritech.tnau.ac.in/nutrition/nutri_dfcnydse_protein.html http://www.agritech.tnau.ac.in/nutrition/nutri_dfcnydse_vitamin.html 17 Reprint 2022  Chapter 2: Human as Organism Activity 2.3. Which nutrient is present in egg-white? Precaution Materials required Egg-white, test-tube, droppers, dilute nitric acid Acids are corrosive. lentils, and milk. Procedure Step 1. Take a small amount of egg white in the test tube. Step 2. Using a dropper, add a few drops of dilute nitric acid on it. Step 3. Record your observations in Table 2.3. Table 2.3 Protein Test Food Item Colour Change with Dilute Nitric Acid Egg white Try similar tests with lentils and milk. Answer the following questions based on activity 2.3. i. What is your observation? ii. What conclusion can you draw? iii. Why is egg white good for health? d. Minerals Minerals are needed by the body in small amounts. It forms about 4% of our body weight. Over a dozen elements are essential for a healthy body. These include sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), chlorine (Cl), copper (Cu), iron (Fe), iodine (I), zinc (Zn), cobalt (Co), manganese (Mn), flourine (F), etc. Deficiency of minerals causes different types of diseases. Table 2.4 shows different types of minerals, their sources, importance, and their deficiency diseases. 18 Reprint 2022  Chapter 2: Human as Organism Table 2.4 Minerals in Food Mineral Sources of Mineral Importance Deficiency Disease Liver, red meat, beans, Formation of red Iron Anaemia. green vegetables, etc. blood cells. Formation of Iodine Sea food, iodised salt, etc. Simple goitre. thyroxin. Milk , dairy products, Formation of Poor growth of bones Calcium vegetables, etc. teeth and bones. and teeth. Water, milk, tooth-paste, Maintains healthy Fluorine Tooth decay. etc. bones and teeth. e. Vitamins Vitamins are essential nutrients required in minute quantities in our diet for keeping the body healthy. They are protective food and do not provide energy. They differ in their functions, and are classified as fat soluble and water soluble vitamins. Fat soluble vitamins include vitamins A, D, E and K, while water soluble vitamins include vitamins B and C. Lack of vitamins in the diet causes deficiency diseases, which affect the skin, hair, bones, eye and general growth of the body. Table 2.5 Vitamins in Food Sources of Deficiency Vitamin Importance Vitamin Disease Carrot, liver, Essential for good vision and Xerophthalmia milk, papaya, A visual health, skin, and immune (Night green vegetables, functions blindness) butter B Cheese, meat, complex carbohydrate metabolism, break eggs, liver, milk, (Group down of amino acids, synthesis of Beriberi bread, grains, of fatty acids green vegetables vitamins) 19 Reprint 2022  Chapter 2: Human as Organism Fruits like Wound healing, reduction in lemons, oranges, allergic responses, cardiovascular C grapes, fresh Scurvy health, development of vegetables like connective tissue components potato, tomatoes Fish, liver, butter, Muscle functioning, bone D cheese, eggs, mineralisation and stability, and Rickets milk multiple immune functions Promote cardiovascular health, Milk and green E skin repair, proper blood flow, Sterility vegetables and clotting Fresh and leafy Process of blood clotting, bone Delays blood K vegetables metabolism and development clotting Do You Know? Your body produces up to 10,000 units of vitamin D in a 20 minute period on a sunny day. That’s 50 times more than the daily recommendation of 200mg (which is equivalent to drinking approximately 10 tall glasses of milk each day). f. Water Up to 60% of the human adult body is water. It does not yield energy, but its absence can lead to death. Water helps in digestion of food and transportation of substances in our body. It is regularly lost from the body through sweat and urine. Therefore, it must be constantly replaced by drinking a minimum of 2 litres of water daily. g. Roughage Roughage, known as fibre, is indigestible fibrous part of the food. It is not a nutrient but an essential content in our diet, which helps the process of digestion. It also prevents constipation and helps bowel movement. Fruits, green vegetables, unpolished rice, whole grains food are important sources of roughage. http://www.wisegeek.com/what-is-roughage.htm 20 Reprint 2022  Chapter 2: Human as Organism Questions 1. Differentiate between kwashiorkor and marasmus. 2. Table 2.6 shows a mess menu of Mendrubling Middle Secondary School. Study, and answer the questions that follow. Table 2.6 Menu Days of a Breakfast Lunch Dinner week Rice, dal, beef, Rice, dal and mixed Bread, jam, egg Monday vegetable curry and vegetable curry and milk fruits Rice, suja and Rice, dal, and Tuesday Rice, vegetable curry fried vegetable vegetable curry Rice, chick pea Rice, dal and Rice, pork and Wednesday and milk tea vegetable curry vegetable curry Fried rice and Rice, dal, emadatsi Rice, dal and Thursday milk tea and fruits vegetable curry Rice, fried Rice, dal, pork, and Rice, dal, papad and Friday vegetable and suja fruits vegetable curry Bread, jam and Rice, dal and Rice, dal and Saturday milk tea vegetable curry Kewadatsi Rice, dal, fish, Fried rice, chick Rice, kewadatsi, fish, Sunday vegetable curry and pea and milk tea curd and fruits fruits i. On which days do the students get more protein? ii. Which is the most common nutrient in the menu? Identify its source. iii. What nutrients would be missing if the vegetables were not on the menu? iv. What deficiency disease are students likely to get if fruits are missing from the menu? 21 Reprint 2022  Chapter 2: Human as Organism 2. The Human Skeleton Learning Objectives On completion of this topic, you should be able to: identify the parts of human skeleton. draw and label the parts of human skeleton. write the functions of the parts of human skeleton. The human body is supported by a framework of bones called skeleton. Bones are hard and strong. They are made of protein collagen, and are heavily deposited with salts of calcium and phosphorus. The functions of the skeleton are to provide support, give shape, produce blood cells and protect organs.Soft substance contained in bone’ cavities called bone marrow produces blood cells. The skeleton also provides attachment for muscles that helps in movement. Figure 2.3 shows the human skeletal system. Human skeleton is divided into Axial skeleton and Appendicular skeleton. Figure 2.3. Human skeleton. 22 Reprint 2022  Chapter 2: Human as Organism Activity 2.4. Labelling of skeleton Materials required 3D model of Human Skeleton Use 3D model and study the parts given in Table 2.7. Answer the questions that follow: Table 2.7 Parts of Skeleton and their Functions. Parts Bone Number Function of Bone Axial Skeleton Skull Cranium 8 Protects brain from external (80 bones) shocks and injuries Facial bones 14 Controls facial expressions and chewing Ribcage True Ribs 14 Protects the heart, lungs and en- Floating Ribs 10 able breathing Sternum 1 Vertebral Backbone 33 Protects the spinal cord column Appendicular Pectoral Clavicle 2 Provides support to the front part skeleton girdles Scapula 2 of the body and movement of (126 bones) forearms Hip bone Support the skeleton and hind limbs Pelvic Sacrum girdles Coccyx Protects the organs such as 2 kidneys, urinary bladder, large intestine and reproductive organs in females Forelimbs 60 Allow us to do a variety of tasks such as lifting and using objects Limbs Hind limbs 60 Use for walking i. Which bone protects the heart? ii. Name two bones that help in lifting things. iii. Why is skull important? 23 Reprint 2022  Chapter 2: Human as Organism 3. The Human Respiratory System Learning Objectives On completion of this topic, you should be able to: identify the parts of human respiratory system. draw and label the parts of human respiratory system. What does the body require to perform various activities in our day to day life? It requires energy derived from the food that we eat. However, energy is not available to the cells directly. Cells carry out a process called respiration which uses oxygen to release energy from food. Oxygen is obtained from the air through the process of breathing. Breathing and respiration are continuous processes that take place in all organisms. Breathing and Respiration Breathing is a process in which animals take in oxygen rich air (inhalation) and give out air containing more carbon dioxide (exhalation). Figure 2.4 shows the organs of respiratory system in human beings. Nose Pharynx Larynx Trachea Bronchioles Bronchi Alveoli Lungs Diaphragm Figure 2.4. Parts of respiratory system. Nose: The respiratory system begins with the nose, which leads to large air filled space called nasal chamber (air passage). Hairs present in the nostrils trap dust particles and purify the air to some extent. Pharynx: It is the passage that carries air and food, and is commonly called throat. 24 Reprint 2022  Chapter 2: Human as Organism Trachea or wind pipe: It is a tube that connects throat to the lungs. Trachea consist of 16 to 20 C-shaped cartilages (ring like), which keeps it open all the time. A thin flap of tissue called the epiglottis is present at the opening of the trachea. It allows air to pass through the larynx and into the rest of the respiratory system. When swallowing food or drink, it covers the entrance to the larynx to prevent food and drink from entering the trachea. The larynx or voice box is located at the upper end of the trachea. It contains two vocal cords, which vibrate to produce sound. Lungs: A pair of lungs is located in the Do You Know? thoracic cavity on either side of the heart. They are soft, spongy and elastic organs. The lungs contain over 300 million Right lungs consists of three lobes and of alveoli. Every minute nearly 6 the left lungs has two lobes. The lower litres of air is breathed in and out. end of trachea divides into two tubes called bronchi (singular, bronchus). These bronchi enter the lungs and further divide into smaller tubes called bronchioles. The bronchioles end as the air sacs known as alveoli (singular: alveolus). The air sacs are surrounded by blood vessels where exchange of gases takes place. The oxygen present in the air we breathe in, reaches the cells through blood vessels. The carbon dioxide released by the cells as waste reach the air sacs through the blood vessels. It is then exhaled during breathing. Breathing is a result of contraction and expansion of muscles called diaphragm. Questions Choose the most appropriate answer. 1. In which process is oxygen used to release energy? i. Photosynthesis ii. Circulation iii. Respiration iv. Reproduction 25 Reprint 2022  Chapter 2: Human as Organism Questions 2. Which sequence is the correct route of the air getting into the lungs of humans? i. nose trachea nasal cavity alveoli bronchioles bronchus ii. nose nasal cavity trachea bronchus bronchioles alveoli iii. nose nasal cavity trachea bronchus alveoli bronchioles iv. nose nasal cavity bronchus trachea bronchioles alveoli 3. The main function of the lungs is to i. break down foods for absorption into the blood. ii. release energy from sugars within the cells. iii. exchange oxygen and carbon dioxide. iv. carry nutrients to all parts of the body. 4. Figure 2.5 shows that animals are dependent on the plants for food and shelter. Sun ? C ar Plants bondioxide Animals Figure 2.5. Identify one other way in which animals are dependent on plants. 5. The walls of trachea do not collapse even when there is less air in it. Why? http://people.eku.edu/ritchisong/301notes6.htm 26 Reprint 2022  Chapter 2: Human as Organism 4. The Human Reproductive System Learning Objectives On completion of this topic, you should be able to: identify the parts of male and female human reproductive system. draw and label the parts of human reproductive system. write the changes that occur during puberty. describe the phases of menstrual cycle. Recognize ways of maintaining personal health and hygiene during menstruation. Reproduction is the process by which living organisms produce young ones of their own kind. Reproduction maintains continuity of life on Earth. There are two basic types of reproduction: asexual reproduction and sexual reproduction. In asexual reproduction, an organism reproduces by the process which does not involve meiosis, or fertilization. In sexual reproduction, a new individual is produced by the fusion of male and female gametes. The gamete produced by male is called sperm and by female is called ovum (plural: ova). Human beings are unisexual organisms. The male and female have separate reproductive system. The onset of sexual maturity in an individual is called puberty. It usually starts at around 11 to 13 years of age. Puberty is accompanied by the development of secondary sexual characteristics. Some of the secondary sexual characteristics in male include: the growth of pubic hair, beard, and moustache on the face. deepening of voice. development of muscles. broadening of shoulders. In female, the changes include: development of breasts. high pitched voice. widening of hips. 27 Reprint 2022  Chapter 2: Human as Organism growth of pubic hair. onset of menstruation (monthly bleeding). The Male Reproductive System The male reproductive system consists of a pair of testes, sperm ducts (Vas deferens), accessory glands, urethra, and penis. Testes are located outside the body sac of skin called scrotum. Sperms are produced in large number inside the testes. They are carried into the urethra by a pair of long tubes called sperm duct. The secretion from accessory glands such as Cowper’s gland, seminal vesicles and prostrate gland mix with sperm to form semen. The semen is released through the penis into the vagina during sexual relation. gland Cowper’s gland Figure 2.6. The male reproductive system. Do You Know? The smallest cell in human is the sperm. http://www.kscience.co.uk/animations/lungs.htm http://www.innerbody.com/ 28 Reprint 2022  Chapter 2: Human as Organism The Female Reproductive System The female reproductive system consists of a pair of ovaries, fallopian tubes, uterus and vagina. Ovaries are located in the lower part of the abdominal cavity. Each ovary produces one ovum every month alternately. An ovum is released into the fallopian tube. During sexual relation, millions of sperms are deposited into the vagina with the help of the penis. The sperms travel up the vagina and uterus and reach the fallopian tube where fertilisation occurs. Uterus Fallopian tube Ovary Cervix Vagina Figure 2.7. The female reproductive system. Menstrual Cycle The ovary usually releases an ovum once in about 28 days. The release of ovum from the ovary is called ovulation. Before the release of an ovum, the walls of the uterus become thick with increased blood supply in preparation to receive the fertilised egg (zygote). After fertilisation the zygote gets implanted in the uterus. If the ovum is not fertilised, it is discharged through the vagina along with the lining of the uterus and blood. This outflow of blood together with the lining of uterus is called menstruation. It usually last for about 3 to 5 days.. The whole process of discharge of blood (menstruation phase), release of hormone called Follicle Stimulating Hormone (follicular phase), release of egg into the ovary (ovulation phase) , and the egg starting to produce progesterone to prepare the body for a potential pregnancy (luteal phase) is called menstrual cycle. Menstruation starts at puberty and puberty, and may stop at about the age of 45 to 50. The onset of menstruation is called menarche, and the stoppage of menstruation is called menopause. 29 Reprint 2022  Chapter 2: Human as Organism se n atio ha tru al p M ens Lute Fo llic ula rp ha se Ovulation phase Figure 2.8. The phases of menstruation cycle. Work in groups Design an activity to create awareness on ways to maintain personal health and hygiene during menstruation. This can be done through advertisement/songs/ poems/posters/arts and crafts, etc. Present your work to the class. Fertilisation The fusion of sperm and ovum is called fertilisation. Fertilisation results in formation of a single celled structure called Zygote. The zygote then begins to divide and forms an embryo.The embryo is implanted in the uterus. The embryo starts to grow at a rapid rate by cell division. The walls of the uterus become thick with increased blood supply to nourish the growing embryo. After six weeks the embryo is called foetus. The foetus takes about 280 days (gestation period) for it to develop completely. 30 Reprint 2022  Chapter 2: Human as Organism Questions 1. What are the differences in the secondary sexual characteristics of male and female? 2. Define the following terms: i. Zygote ii. Menstruation iii. Semen iv. Reproduction v. Ovulation 31 Reprint 2022  Chapter 2: Human as Organism 5. Human Nervous System Learning Objectives On completion of this topic, you should be able to: identify the parts of human nervous system. write the functions of the brain, spinal cord and nerve. Activity 2.5. Recognise and remember Work in groups Materials required A bag(opaque) and some objects Procedure Step 1. Show all the objects to the group members. Step 2. Put the objects in the bag. Step 3. Take turns to identify the objects by feeling them in the bag. Now answer the following questions. i. List down the objects you could identify. ii. How are you able to recognise the objects in the bag? iii. How does the brain recognise the objects? iv. Which part of the nervous system is involved in carrying the impulses from hand to the brain? The human body carries out many activities, consciously or unconsciously, for example, breathing, beating of heart, lifting off hands on touching a hot object, or kicking a ball. All these activities occur in a coordinated manner. The nervous system helps to coordinate the activities of the human body. The nervous system includes the brain, spinal cord and the nerves. 1.http://www.kscience.co.uk/animations/lungs.htm http://people.eku.edu/ritchisong/301notes6.htm 32 Reprint 2022  Chapter 2: Human as Organism Brain: The brain is a very delicate organ, well protected inside the brain Brain box (cranium) of the skull. It is covered by a membrane called meninges. The brain is divided into three parts – the cerebrum, cerebellum and the Spinal medulla oblongata. The cerebrum cord is the largest part of the brain. Nerves It controls thinking, reasoning, memory, speech and vision. The cerebellum is situated at the base of the cerebrum. It coordinates muscle movements and maintains balance of the body. The medulla oblongata is the lowest portion of the brain. It controls activities, which are not under our will such as heartbeat, breathing, sneezing and digestion. Figure 2.9. The human nervous system. Spinal cord: It is a cylindrical structure that arises from the brain and runs along the vertebral column (backbone). It carries messages from the muscles and skin to the brain. It also carries messages from the brain to the muscles of the limbs and other parts of the body. Cerebrum Medulla oblongata Cerebellum Figure 2.10. The human brain. Nerve: A nerve is a thread-like structure arising from the brain and spinal cord, and spreading to the different parts of the body. It is formed by a bundle of neurons. A neuron is a single nerve cell. It is the functional and structural unit of 33 Reprint 2022  Chapter 2: Human as Organism nervous system responsible for carrying impulses. Depending upon the direction Nerve in which they carry the impulse, nerves are of three types. Sensory nerves carry messages (impulse) from sensory organs (eyes, ears, tongue, Blood Connective nose, and skin) to the brain. vessel tissue Motor nerves carry messages (impulse) from the brain to the different parts of Figure 2.11. Nerve. the body. Mixed nerves consist of both sensory and motors nerves. Questions 1. Copy Figure 2.12 in your note book, and make the boundaries of cerebrum, cerebellum and medulla oblongata. Figure 2.12. 2. Why do you think it is not wise to hit hard on someone’s back? 3. Tshewang fell down from the staircase. He could neither walk properly nor remember what had happened to him after the fall. Which parts of the brain do you think were affected? http://people.eku.edu/ritchisong/301notes6.htm 34 Reprint 2022  Chapter 2: Human as Organism 6. Health and Diseases Learning Objectives On completion of this topic, you should be able to: explain health and disease. identify some of the common diseases prevalent in Bhutan. explain symptoms and preventive measures of common diseases. explain the importance of personal hygiene. According to the World Health Organization (WHO), human health is defined as a “state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity”. A disease is a condition in which there is an abnormal functioning of the body. Some diseases are present from the birth, whereas some diseases are acquired during lifetime. Diseases can be communicable or non-communicable. a. Communicable Diseases These diseases are transmitted from one person to another. They are always caused by disease causing organisms called pathogens. Based on the types of pathogens, communicable diseases are of the following types: i. Diseases caused by bacteria Bacteria are present in air, water, soil, and in living and non-living things. They cause many diseases, some of which are: Figure 2.13. Tuberculosis bacteria. 35 Reprint 2022  Chapter 2: Human as Organism Table 2.8 Diseases Caused by Bacteria Name of Caused by Symptom Prevention Diagram disease Mycobacterium Fever, cough, Immunising tuberculosis sputum the child with containing blood, BCG (bacillus pain in the chest, of calmette and loss of weight, loss Guerin) vaccine, Tuberculosis of appetite, and tiredness Disinfecting the utensil and other materials used by the patient Salmonella typhi High fever, Proper sanitation, vomiting, regular hand headache, washing and abdominal pain, keeping the flies Typhoid and diarrhoea under control Vibrio cholerae Acute diarrhoea, Safe drinking vomiting, water, eating abdominal properly cooked pain, and rapid food and covering dehydration the edibles Cholera Protozoa, virus Loose watery Wash your hands and bacteria stool, abdominal with soap for at cramp, abdominal least 20 seconds pain, fever, blood Diarrhoea Use hand sanitizer in the stool, mucus in the when washing isn’t stool, and bloating possible, Cover the edible items, maintain hygiene 36 Reprint 2022  Chapter 2: Human as Organism ii. Diseases caused by Virus Fever, headache, Eat fruits and vegetables, sore throat, coughing avoid crowded places, and sneezing, body pain use handkerchief while coughing or sneezing High fever, headache, difficulty in swallowing food, fear of water (Hydrophobia) Fever, headache, sneezing, sore throat, appearance of red spot Isolate patients, Immunise the vaccinate. animals Anti-rabies vaccines in case of bites by rapid animals Fever, lose of body Use sterilised needles, weight, continuous screen blood before transfusion, diarrhoea, swelling of use condom while having sex, different glands fatigue, use new blades for shaving and sweating at night, hair cut decreased immunity Do You Know? AIDS is not spread through insect bite, hugging, sharing meals, toilets, clothing, utensils, shaking hands, coughing, sneezing or caring for AIDS patient. Activity 2.6. AIDS education Design a video to create awareness on AIDS using block programming or any other software and present to the class. 37 Reprint 2022  Chapter 2: Human as Organism iii. Diseases caused by protozoa Protozoa is a unicellular organism that can only multiply within a body of another organism. An example of the disease caused by protozoa is malaria. Malaria Malaria is a common disease caused by the protozoa called Plasmodium vivax. In Bhutan, it is mostly prevalent in the southern region. Female Anopheles mosquitoes transmit the parasite from an infected person to an uninfected person. Some of the common symptoms are high fever, shivering, muscle pain, profuse sweating, headache, loss of appetite, and fatigue. Malaria can be prevented by using insecticide treated mosquito nets, mosquito repellents, covering exposed parts of your body during evening or night, keeping the surrounding clean, preventing pooling of water, and covering water containers. iv. Disease caused by parasitic worms Parasitic worms are those worms that live inside the body of animals. Round worm (Ascaris) is an example of parasitic worms. The Ascaris has elongated body with tapering ends. It causes a disease called Ascariosis. Ascariosis Ascariosis is an infection of the intestinal tract in humans by Ascaris. The worm derives the food from the intestine causing damages to it. The disease makes a person weak and anaemic (less number of red blood cells). It causes pain in the stomach, vomiting and diarrhoea. The eggs of female worm pass out along with the stool and contaminate soil, food and water. When a person takes contaminated food and water, the eggs enter his or her intestine where they hatch and grow. Ascariosis can be prevented by drinking safe water, washing fruits and vegetables with clean water before eating, and washing hands properly before and after eating. v. Disease caused by fungi Fungi are large group of organisms which do not have chlorophyll. They include mushrooms, yeasts and moulds. Fungi cause number of diseases in humans. Some of the diseases caused by fungi are: 38 Reprint 2022  Chapter 2: Human as Organism Ringworm It is an infectious disease of the skin caused by fungus. It produces a ring shaped patch on the skin; hence, the name ringworm. It can be transmitted from an infected person through contact of infected skin, and sharing combs, brushes, and other personal items. The infected area of the skin becomes red, inflamed and Figure 2.14. Ringworm infection. scaly. It may be mildly irritating or very itchy. It can be prevented by avoiding contact with infected person and not sharing personal items. It is also important to maintain personal cleanliness and clean surroundings. It can be treated by using anti-fungal creams, which can be obtained from hospitals or BHUs. Athlete’s foot It is a fungal infection that affects skin between the toes and sole of the foot. It can spread from infected person through direct skin contact, and indirectly, through towels, socks, shoes and floors. The infected area becomes red and scaly with small blisters. Some of the preventive Figure 2.15. Athelete’s foot. measures are washing the feet everyday and allowing them to dry before putting on shoes and socks. Wearing sandals, leather shoes, woollen or cotton stockings are also some of the preventive measures. It can be treated by using anti-fungal creams and powders. vi. Disease caused by mites If you have itchy rashes between fingers, palms, soles and genitals, this infection is due to the skin disease called scabies. It is caused by itch mites (Sarcoptes scabiei). Scabies is spread from an infected person to another person through skin to skin contact, and by sharing clothing or bedding. Maintaining personal hygiene can be the best prevention from contracting scabies. 39 Reprint 2022  Chapter 2: Human as Organism b. Non-Communicable Diseases Diseases, which do not spread from one person to another are called non- communicable diseases or non-infectious diseases. They are not caused by pathogens. Some examples are allergies, diabetes, night blindness, asthma and heart diseases. Use your school library or browse internet to find out more about non- communicable diseases and make a display of the information in the class. c. Personal Health and Hygiene Good personal health and hygiene is one of the most effective ways to protect us from illness. The major aspects of personal health and hygiene are: Cleanliness: It involves taking bath daily, washing hands before eating and after visiting the toilets, washing clothes regularly, etc. It also involves brushing the teeth once in the morning and before going to bed, clipping nails, and keeping hair tidy. Rest and sleep: Our daily activities make our body tired. Therefore, for proper mental and physical health, children should sleep at least 8 hours, while adults should sleep at least for 6 hours. Avoiding bad habits: You should never indulge in bad habits like smoking, chewing doma, and tobacco, drinking alcohol and abusing drugs. These habits are injurious to your health. Physical exercise: Regular physical activities are essential for proper growth and functioning of the body. They help the person to be physically healthy and mentally sound. Various games such as football, volleyball, basketball, badminton, cycling and taking regular walks (at least 30 minutes) are good physical exercises. However, with advancement of science and technology, the way we live our life has changed. These days, many people lead a sedentary lifestyle by watching television, surfing internet, playing video, games and driving cars. These increase the risk of obesity, which leads to hypertension and diabetes. 40 Reprint 2022  Chapter 2: Human as Organism Activity 2.7. Personal health audit Take this simple test sincerely to find out how healthy your lifestyle is. Put a score for each indicator: 2 for agree, 1 for sometimes and 0 for disagree. Total up the scores for each health area. Know your life style by comparing the grand total in each area with the scale given in Table 2.9. Table 2.9 Checklist for Personal Habits Agree Sometimes Disagree Health Indicator Total (2) (1) (0) Drugs 1 I do not chew doma 2 I do not chew tobacco 3 I do not smoke cigarette 4 I do not drink alcohol 5 I do not abuse drugs Grand Total Eating habits 1 I eat food on time 2 I eat fruits and vegetables 3 I drink 2 to3 litres of water daily 4 I avoid fast food 5 I avoid fizzy drinks Grand Total Exercises 1 I play games in school 2 I like some physical work 3 I sleep for about eight hours 4 I jog everyday 5 I walk to school almost every time Grand Total 41 Reprint 2022  Chapter 2: Human as Organism Stress 1 I sleep on time I do not like to surf internet for long 2 hours I do not like to use cell phone 3 everyday I do not read books continuously for 4 hours I do not like to play video games and 5 watch television all the time Grand Total Personal Hygiene 1 I take bath regularly 2 I brush my teeth regularly 3 I wear clean clothes and dress neatly I cut my nails and groom my hair 4 regularly I keep my room/house/surrounding 5 clean Grand Total Scale for scores Scores of 9 and 10 Excellent! Your scores show that you are practising good health habits. As long as you continue to do so, this area should not pose a serious health risk. You are setting a good example for your family and friends to follow. Scores of 6 to 8 Your health practices in this area are good, but there is room for improvement. Scores of 3 to 5 Your scores show that there are health risks in this area. It is important for you to change these behaviours quickly through help from your friends, teachers and parents. Scores of 0 to 2 Be aware! Your scores show that you are taking serious and unnecessary risks 42 Reprint 2022  Chapter 2: Human as Organism with your health. Perhaps, you are not aware of the risks and what to do about them. Consult a professional counselor. Questions 1. Give reasons for the following statements: a. Always drink safe water. b. Always wash your hands before eating. c. Give ORS to people suffering from diarrhoea. d. Keep the edibles covered. 2. Study Figure 2.16 to answer questions ‘a’ and ‘b'. Figure 2.16. a. Predict the disease that the child and mother would get without the net. b. List other preventive measures for the disease. 3. There is an outbreak of cholera in your area. How will you protect yourselves from cholera? 43 Reprint 2022  Chapter 2: Human as Organism Exercise Multiple Choice Questions 1. A child shows poor physical growth with loose folds of skin, very thin arms and legs, and is very lethargic. Identify the disease. A. Kwashiorkor B. Marasmus C. Anaemia D. Goitre 2. The total number of ribs present in human body is? A. 10. B. 12. C. 24. D. 36. 3. The nasal chambers open into A. pharynx. B. trachea. C. oral cavity. D. lungs. 4. Fertilization is the process by which the zygote is formed. Where does this process take place? A. Uterus. B. Oviduct. C. Ovary. D. Vagina. 5. Dorji is solving a mathematical problem. Which part of the brain is he using? A. Medulla oblongata. B. Cranium. C. Cerebellum. D. Cerebrum. 44 Reprint 2022  Chapter 2: Human as Organism 6. A person is bitten by an animal. Which of the following diseases is he likely to be infected with? A. Cholera. B. Dysentery. C. Ascariosis. D. Rabies. 7. Scurvy is a disease that sailors often got on long voyages. It was discovered that scurvy could be prevented by eating oranges and lemons. This suggests that scurvy is a disease caused by A. exposure to sea air. B. microorganism. C. a nutritional deficiency. D. lack of exercise. Check whether the following statements are True or False. Correct the false statements. 1. Scapula is also called as collar bone. 2. Respiration is the process of taking in oxygen rich air and giving out carbon dioxide rich air. 3. The spinal nerve arises from the brain. 4. Measles is caused by Rhabdovirus. 5. Deficiency of iron in a meal causes goitre. Match the following Column A Column B 1. Vaccine used for treating tuberculosis. A. Sperm 2. The main part of the skeleton that provides B. BCG support to the ribs at the back. 3. The smallest units of the nervous system C. Alveoli which carries impulse. 4. Special cells produced in the testes. E. Ovum 5. The terminal ends of the respiratory system. F. DOT G. Neuron H. Backbone 45 Reprint 2022  Chapter 2: Human as Organism Answer the following questions 1. Define the following terms. a. Nutrient b. Axial skeleton c. Marasmus d. Disease 2. Differentiate between the following, based on what is given in the bracket. a. Scurvy and Rickets (deficient nutrient) b. Protein and carbohydrates (composition) c. Breathing and Respiration (process) d. Cerebrum and Cerebellum (function) e. Infectious diseases and non-infectious diseases (cause) 3. Give reasons for the following statements. a. During the Second World War, night pilots were fed with carrot juice. b. In a place where lots of polished rice was eaten, it was found that many people suffered from paralysis of limbs. c. A woman after menopause may not produce children. 4. Complete Table 2.10. Table 2.10 Minerals and Deficiency Diseases Minerals Importance Deficiency disease Sources........................................ Anaemia Liver and meat Iodine.................... Goitre.................... Milk and.................... Bone formation.................... vegetables Fluoride.................... Tooth decay.................... 46 Reprint 2022  Chapter 2: Human as Organism 5. Copy and label Figure 2.17. 1 2 7 3 8 4 5 9 6 Figure 2.17. 6. Figure 2.18 shows a diagram of human reproductive system. Study it carefully and answer the following questions. B C A Figure 2.18. a. In which label does the development of embryo takes place? b. Write the function of the part labelled A. c. Name the organ system. d. What would happen if the part labelled B is cut off? 7. Name different types of nerves and write their functions. 8. A person is showing the following symptoms: chest pain, dry cough, loss of appetite, fever, fatigue and blood in the sputum. a. What could be the disease the person is suffering from? b. Suggest some ways to prevent this disease. 47 Reprint 2022  Chapter 2: Human as Organism 9. Case Study HIV Infection: A Report A ccording to UNAIDS’ estimations, there are less than 1,000 people living with HIV, and the total number identified as HIV positive in the country stands at 403 in 2015, since the first case was detected in 1993. The report mentioned that 91% of HIV infections are due to unsafe sexual practices such as multiple partners, casual sex and low condom use. Table 2.11 and Table 2.12 shows the HIV cases as per gender and the mode of transmission. Table 2.11 Case of HIV by Age Group Age group Male Female Total < 5 years 6 16 22 5-14 years 4 4 8 15-19 years 1 10 11 20-24 years 21 41 62 25-29 years 56 56 112 30-39 years 81 51 132 40-49 years 29 17 46 50+ years 6 4 10 204 199 403 Table 2.12 HIV Cases of HIV by Mode of Transmission Mode of Transmission Total Sexual route 91% Mother to child 7% Intravenous drug use (probable) 1% Blood transfusion (outside) 1% Other 2% 100% [Source: National AIDS Control Programme, Department of Public Health, MoH.] 48 Reprint 2022  Chapter 2: Human as Organism Answer the following questions based on the above case study. i. Insert the data from Table 2.12 in a spreadsheet and represent the information in a bar graph. ii. Which age group has the highest number of AIDS patients? iii. Identify the most prevalent mode of transmission. iv. What are the main reasons for HIV infection? 49 Reprint 2022  Chapter 3 Green Plant We know that all green plants synthesize their own food using carbon dioxide and water in the presence of sunlight. This process by which green plants manufacture food substance (glucose) from carbon dioxide and water using sunlight is known as photosynthesis. Hence, green plants are called producers or autotrophs. 1. Photosynthesis Learning Objectives On completion of this topic, you should be able to: explain photosynthesis. investigate factors that affect photosynthesis. write the word equation of photosynthesis. explain the importance of photosynthesis. http://www.biology4kids.com/files/plants_photosynthesis.html http://dendro.cnre.vt.edu/forestbiology/photosynthesis.swf 50 Reprint 2022  Chapter 3: Green Plant The process of photosynthesis is represented by the following equation: Sunlight Carbon dioxide + Water Glucose + Oxygen + Water Chlorophyll Sunlight 6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O Chlorophyll Most green plants convert glucose into starch as soon as it is formed during photosynthesis. Several molecules of glucose combine to form starch. The major portion of the oxygen produced during photosynthesis diffuses out into the atmosphere through stomata. The water produced during photosynthesis may be used again in the process or lost in the form of vapour. Activity 3.1. Photosynthesis Figure 3.1 represents the process of making food by green plant. Use this diagram to answer the Lig following questions. ht en Water vapour ergy i. Identify any two materials released by plant shown in the diagram that the plant needs for Oxygen making food. released by plant ii. Which part of the plant is directly involved in making food? Water from iii. Name the gas given out by ground the rat which is used by the plants in producing its food. Food from leaves Rat iv. Define the process taking place. Carbon dioxide from the air enters the leaf by diffusion through small openings, called stomata, present on the surface of the leaf. Plants absorb water from the soil Figure 3.1. Process of making food by green plant. 51 Reprint 2022  Chapter 3: Green Plant through their roots. This water is then transported to the leaves through small tube called xylem. Activity 3.2 Openings in a leaf Materials required Microscope, glass slide, water, forceps and green fleshy leaf. Procedure Step 1. With the help of forceps, take a peel from the dorsal side of the green fleshy leaf. Step 2. Mount it on the glass slide containing a drop of water. Make sure it lies flat and not folded. Step 3. Observe it under the microscope. Step 4. Draw the bean seed shaped structures that you see. These structures are called guard cells. The opening between the guard cells is called stoma (plural: stomata). Activity 3.3. Is sunlight necessary for photosynthesis? Materials required Potted plant, black paper, scissors, paper clip, iodine solution, dropper, petri dish, beaker, spirit lamp, spirit, test tube, test tube holder, forceps, water wire gauze, tripod stand and match box. Procedure Step 1. Keep the potted plant in a dark place for two to three days. Step 2. Cover one of its leaves with black paper on which a design is cut as in Figure 3.2. Support the paper with the clips. The leaf should remain attached to the plant. Step 3. Keep this plant in the Sun for 4 to 6 hours. Step 4. Pluck the leaf covered by the black paper and test it for the presence of starch (iodine test). 52 Reprint 2022  Chapter 3: Green Plant Starch present Paper clip Exposed to light Starch absent Black paper Potted plant Figure 3.2. Sunlight for photosynthesis. Answer the following questions based on Activity.3.3 i. What did you observe during the iodine test? Give reasons for your observation. ii. What can you conclude from the experiment? iii. Why was black paper used to cover the leaf? iv. Why was plant kept in the dark place for two to three days? v. Can you repeat this experiment outside with any plant from your school garden? Why? Activity 3.4. Is carbon dioxide necessary for photosynthesis? Materials required Potted plant, conical flask, split cork, potassium hydroxide (KOH), iodine solution, dropper, spirit lamp, petri dish, beaker, test tube holder, forceps, water, match box, wire gauze , tripod stand and petroleum jelly. Procedure Step 1. Keep the potted plant in a dark place for two to three days. Step 2. Insert one of its leaves through a split cork into the conical flask containing potassium hydroxide (potassium hydroxide absorbs carbon dioxide).The leaf should remain attached to the plant. Make the mouth of the conical 53 Reprint 2022  Chapter 3: Green Plant flask air tight by using petroleum jelly. Step 3. Keep the set-up in the sunlight for 4 to 6 hours. Step 4. Take the leaf from the conical flask. Potassium Step 5. Take one more leaf from the same hydroxide plant. Step 6. Test both the leaves for presence of starch. Answer the following questions based on Activity 3.4. Figure 3.3. Carbon dioxide for i. Suggest a possible hypothesis for the photosynthesis. experiment. ii. Write your observations made in the two leaves during the iodine test. iii. Give reasons for the observations. iv. What do you infer from the experiment? v. Why is the mouth of the conical flask made air tight? vi. What difference will you notice in the result if sodium hydroxide is used instead of potassium hydroxide? Activity 3.5. What gas is produced during photosynthesis? Materials required Beaker, beehive self , test-tube, funnel, water, glowing splint, spirit lamp, match box and aquatic plant. Procedure Step 1. Place the beehive shelf at the bottom of the beaker. Place the aquatic plant in such a way that its cutting ends remain towards the stem of the funnel and cover with the funnel. Step 2. Pour water into the beaker in such a way that the stem of the funnel remains beneath the water level. Step 3. Fill the test tube completely with water. Step 4. Place your thumb on the mouth of the test tube so that no air enters the test tube. Carefully invert the test tube over the stem of the funnel as 54 Reprint 2022  Chapter 3: Green Plant shown in the Figure 3.4. Step 5. Place the apparatus in sunlight and observe it for about ten minutes. Step 6. Lift the test tube from the water and test the gas immediately by bringing a glowing splint near the mouth of the test tube. Gas Light Water Aquatic plant Beehive self Figure 3.4. Gas produced during photosynthesis. Answer the following questions based on Activity 3.5. i. Suggest a hypothesis for the above experiment? ii. What happens to the level of water in the test tube after some time? Give reason. iii. What happens to the glowing splint when brought near to the mouth of the test tube? iv. Name the gas collected in the test tube. v. What precautions should be taken during the experiment? Importance of photosynthesis i. Provides food: Photosynthesis is the process by which food is produced for all living things. ii. Provides oxygen: During photosynthesis oxygen is released into the atmosphere, which supports all life on the earth. Questions 1. What is photosynthesis? 2. Life cannot be possible without green plants. Give reasons. 55 Reprint 2022  Chapter 3: Green Plant 2. Nutrients for Plants Learning Objectives On completion of this topic, you should be able to: identify some of the essential nutrients for plants and their sources. categorise plant nutrients into macronutrients and micronutrients. identify deficiency symptoms of primary nutrients in plants. Besides sunlight, carbon dioxide and water, plants also require certain elements for their normal growth and development. These elements are called nutrients. The nutrients found in the soil are absorbed by the roots of plants in the form of solution. The soil obtains these nutrients from the decayed plants and animals, or from fertilisers. When plants do not get the right amount of nutrients, they become unhealthy and show deficiency symptoms. Plants require as many as seventeen essential nutrients for growth, which are divided into two groups: macronutrients and micronutrients. Macronutrients are those nutrients, which are required by plants in large amounts. They are further categorized into primary nutrients and secondary nutrients. Primary nutrients are those nutrients without which plants cannot grow at all. The primary nutrients are nitrogen (N), phosphorous (P), and potassium (K) as given in Table 3.1. Table 3.1 Primary Nutrients