Respiration in Organisms PDF

JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION 10 RESPIRATION IN ORGANISMS O ne day Yasir was eagerly from? Can you say why your parents waiting to meet his insist that you should eat regularly? The grandparents...

JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION 10 RESPIRATION IN ORGANISMS O ne day Yasir was eagerly from? Can you say why your parents waiting to meet his insist that you should eat regularly? The grandparents who were food has stored energy, which is released coming to the town after a year. He was in during respiration. Therefore all living a real hurry as he wanted to receive them organisms respire to get energy from at the bus stop. He ran fast and reached food. During breathing, we breathe in air. the bus stop in a few minutes. He was You know that air contains oxygen. We breathing rapidly. His grandmother asked breathe out air which is rich in carbon him why he was breathing so fast. Yasir dioxide. The air we breathe in is told her that he came running all the way. transported to all part of the body and But the question got struck in his mind. He ultimately to each cell. Inhaled oxygen wondered why running makes a person from the air helps in the breakdown of breathe faster. The answer to Yasir food. The process of breakdown of food in question lies in understanding why do we the cell with the release of energy is called breathe. Breathing is a part of respiration. cellular respiration. Cellular respiration Let us learn about respiration. takes place in the cells of all organisms. In the cell, the food (glucose) is broken 10.1 WHY DO WE RESPIRE? down into carbon dioxide and water using You know that all organisms are oxygen. When breakdown of glucose made of small microscopic units called occurs with the use of oxygen it is called cells. A cell is the smallest structural and aerobic respiration. Food can also be functional unit of an organism. Each cell broken down, without using oxygen. This of an organism performs certain function is called anaerobic respiration. such as nutrition, transport, excretion and Breakdown of food releases energy. reproduction. To perform these functions, C6H12O6 + 6O2 " 6CO2 + 6H2O + the cell needs energy. Even when we are Energy eating, sleeping or reading we require Glucose with use of oxygen release energy. But, where does this energy come carbon dioxide, water and energy. RESPIRATION IN ORGANISMS 126  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION Glucose with the use of oxygen breakdown of glucose produces lactic carbon dioxide + water + energy acid which causes muscle cramps. We You should know that there are get relief from cramps after a hot water some organisms such as yeast that can bath or a massage. Can you guess why it survive in the absence of air. They are is so? Hot water bath or massage called anaerobes. They get energy improves circulation of blood. As a result, through anaerobic respiration. In the the supply of oxygen to the muscle cells absence of oxygen, glucose breaks down increases. The increase in the supply of into alcohol and carbon dioxide, as given oxygen re sults in the comp lete below: breakdown of lactic acid into carbon Glucose without the use of oxygen dioxide and water. alcohol + carbondioxide + energy Yeasts are single- celled organisms. They respire anaerobically and during this process yield alcohol. They are, therefore, used to make wine and beer. Our muscle cells can also respire anaerobically, but only for a short time, when there is a temporary deficiency of oxygen. During heavy exercise, fast running (Fig.10.1), cycling, walking for many hours or heavy weight lifting, the demand for energy is high, but the supply Fig.10.1 : During exercise, some muscles may of oxygen is very less in the muscle cells respire anaerobically to fulfill the demand of energy: In the absence of oxygen Glucose (In Muscle) 10.2 BREATHING Lactic acid + Energy Activity 10.1 Have you ever wondered why you CAUTION get muscle cramps after heavy exercise? Do this activity under the supervision The cramps occur when muscle cells of your teacher. respire anaerobically. The partial Close your nostrils and mouth RESPIRATION IN ORGANISMS 127  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION tightly and look at a watch. What did you according to the requirement of oxygen feel after some time? How long were you by the body? Let us find out by doing the able to keep both of them closed? Note following activity. down the time period for which you could hold your breath (Fig. 10.2). So, now you know that you cannot survive for long without breathing. Breathing means taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organs. The talking in of air rich in oxygen into the body is called inhalation and giving out of air rich in carbon dioxide is Fig.10.2 : Holding breath known as exhalation. It is a continuous process which goes on all the time and Yasir noticed that when he throughout the life of an organism. released his breath after holding The number of times a person it for some time, he had to breathe heavily. Can you tell breathes in a minute is termed as the him why it was so? breathing rate. During breathing inhalation and exhalation takes place alternately. A breath means one inhalation Activity 10.2 plus one exhalation. Would you like to find Generally we are not aware that we out your breathing rate? Do you want to are breathing. However, if you try you can know whether it is constant or it changes count your rate of breathing. Breathe in Table 10.1: Changes in breathing rate under different conditions Name of the classmate Breathing rate Normal After a brisk walk After running At rest for 10 minutes fast for 100 m Self RESPIRATION IN ORGANISMS 128  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION and out normally. Find out how many Activity 10.3 times you breathe in and breathe out in a Figure 10.3 shows the various minute? Did you inhale the same number activities carried out by a person during a of times as you exhale? Now count your normal day. Can you say in which activity, breathing rate (number of breaths/ the rate of breathing will be the slowest minute) after brisk walk and after running. and in which it will be the faster? Assign Record your breathing rate as soon as number to the picture in the order of you finish and also after complete rest. increasing rate of breathing according to Tabulate your findings and compare your your experience. breathing rates under different conditions with those of your classmates.. From the above activity, you must have realized that whenever a person needs extra energy, he/ she breathes faster. As a result more oxygen is supplied to our cells. It speeds up the breakdown of food and more energy is released. Does this explain why we feel hungry after a physical activity? When you feel drowsy, does your breathing rate slow down? Does your Fig.10.3 : Variation in the breathing during body receive sufficient oxygen? different activities On an average, an adult human being Saba wants to know why at rest breathes in and out 15 -18 times we yawn when we are sleepy or drowsy. in a minute. During heavy exercise, the breathing rate can increase upto 25 times per minute. While we exercise, 10.3 HOW DO WE BREATHE? not only do we breathe fast, we also Let us now learn about the take deep breaths and thus inhale more mechanism of breathing. Normally we oxygen. take in air through our nostrils. When we RESPIRATION IN ORGANISMS 129  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION inhale air, it passes through our nostrils During inhalation, ribs move up into the nasal cavity. From the nasal and outwards and diaphragm moves cavity, the air reaches our lungs through down. This movement increases space in the windpipe. Lungs are present in the our chest cavity and air rushes into the chest cavity (Fig. 10. 4). This cavity is lungs. The lungs get filled with air. During surrounded by ribs on the sides. A large exhalation, ribs move down and inwards, muscular sheet called diaphragm forms while diaphragm moves up to its former the floor of the chest cavity (Fig. 10. 4). position. This reduces the size of the Breathing involves the movement of the chest cavity and air is pushed out of the diaphragm and the rib cage. lungs (Fig. 10.5). These movement in our Nasal passage Pharynx Oral cavity Trachea Lungs Diaphragm Ribs Fig 10.4 : Human respiratory system The air around us has various types of unwanted particles, such as smoke, dust, pollen, etc. When we inhale, the particles get trapped in the hair present in our nasal cavity. However, sometimes these particles may bypass the hair in the nasal cavity. Then they irritate the lining of the cavity, as a result of which we sneeze. Sneezing expels these foreign particles from the inhaled air and a dust- free, clean air enters our body. TAKE CARE: When you sneeze, you should cover your nose so that the foreign particles you expel are not inhaled by other persons. RESPIRATION IN ORGANISMS 130  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION body can be felt easily. Take a deep Activity 10.4 breath. Keep your palm on the abdomen. Take a deep breath. Measure the What do you find? size of the chest with a measuring tape After having learnt that during (Fig. 10.6) and record your observations breathing there are changes in the size of in Table 10.2. Measure the size of the chest cavity, children got involved in the chest when expanded and indicate which chest expansion competition. Everyone classmate shows the maximum was boasting that she/ he could expand it expansion of the chest. the maximum. How about doing this We can understand the activity in the class with your classmate? mechanism of breathing by a simple model. Smoking damages our lungs. Smoking Activity 10.5 is also linked to cancer. It must be Take a wide plastic bottle. Remove avoided. the bottom of the bottle. Get a Y- shaped Diaphragm Diaphragm moves down moves back (b) Exhalation (a) Inhalation Fig.10.5 : Mechanism of breathing in human beings Table 10.2 Effect of breathing on the chest size of some classmates Name of the Size of the chest Classmates During inhalation During exhalation Difference in size RESPIRATION IN ORGANISMS 131  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION glass or plastic tube. Make a hole in the lid 10.4 WHAT DO WE BREATHE OUT? so that the tube may pass through it. To Activity 10.6 the forked end of the tube fix two deflated Take a slender, clean test tube or a balloons. Introduce the tube into the bottle glass/ plastic bottle. Make a hole in its lid as shown in Fig. 10.7. Now cap the bottle. and fix it on the bottle. Pour some freshly Seal it to make airtight. To the open base prepared lime water in the test- tube. of the bottle tie a thin rubber or plastic Insert a plastic straw through the hole in sheet using a large rubber band. the lid in such a way that it dips in lime water. Now blow gently through the straw a few times (Fig. 10.8). Is there a change in the appearance of lime water? Can you explain this change on the basis of what you have learnt earlier ? You are aware that the air we inhale or exhale is a mixture of gases. What do we exhale? Do we exhale only carbon dioxide or a mixture of gases along with it? You must have also observed that if you exhale on a mirror, a film of moisture appears on its surface. Fig.10.6 : Measuring chest size From where do these droplets come? To understand the expansion of the lungs, pull the rubber sheet from the base downwards and watch the balloons. Plastic Next, push the rubber/ plastic sheet up bottle and observe the balloons. Did you see Balloons any changes in the balloons? What do the balloons in this model Rubber represent? What does the rubber sheet sheet represent? Now you should be able to explain Fig 10.7 : Model to show the mechanism of the mechanism of breathing. breathing RESPIRATION IN ORGANISMS 132  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION How do other organisms breathe? Do they also have lungs like those of human beings? Let us find out. Yasir wants to know if Straw cockroaches, snails, fish, earthworms, ants and mosquitoes also have lungs. Lime water Fig 10.8 : Effect of exhaled air on lime water Cockroach: A cockroach has small openings on the sides of its body. Other Yasir wants to know how insects also have similar openings. These much air a person can hold in openings are called spiracles (Fig. 10.9). the lungs. Insects have a network of air tubes called tracheae for gas exchange. Oxygen rich The percentage of oxygen and carbon air rushes through spiracles into the dioxide in inhaled and exhaled air. tracheal tubes, diffuses into the body Inhaled air Exhaled air tissue and reaches every cell of the body. 21% oxygen 16.4% oxygen Similarly, carbon dioxide from the cells goes into the tracheal tubes and moves Lungs out through spiracles. These air tubes or tracheae are found only in insects and not 0.04% Carbon 4.4% Carbon in any other group of animals. dioxide dioxide Tracheae 10.5 BREATHING IN OTHER ANIMALS Animals such as elephants, lions, cows, goats, frogs, lizards, snakes and birds have lungs in their chest cavities like Fig.10.9 : Tracheal system the human beings. RESPIRATION IN ORGANISMS 133  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION Earthworm: You have already learnt that You have studied in previous class earthworms breathe through their skin. that gills in fish help them to use oxygen The skin of an earthworm feels moist and dissolved in water. Gills are projections of slimy on touching. Gases can easily pass the skin. You may wonder how gills help in through them. Though frogs have a pair of breathing. Gills are well supplied with lungs like human beings, they can also blood vessels (Fig.10.10) for exchange of breathe through their skin, which is moist gases. and slippery. 10.7 DO PLANTS ALSO RESPIRE? Like other organisms, plants also Yasir has seen in television programmes that whales and respire for their survival as you have dolphins often come up to the already learnt. They also take in oxygen water surface. They even release from the air and give out carbon dioxide. a fountain of water sometimes In the cells oxygen is used to breakdown while moving upwards. Why do they do so? glucose into carbon dioxide and water as in other organisms. In plants each part can independently take in oxygen from 10.6 BREATHING UNDER WATER the air and give out carbon dioxide. You Can we breathe and survive in have already learnt in chapter 1 that the water? There are many organisms which leaves of the plants have tiny pores called live in water. How do they breathe under stomata for exchange of oxygen and water? carbon dioxide. Gills Saba wants to know whether roots, which are underground also, take in oxygen. If so, how? Like all other living cells of the plants, the root cells also need oxygen to Fig.10.10 : Breathing organs in fish generate energy. Roots take up air from the air spaces present between the soils RESPIRATION IN ORGANISMS 134  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION particles (Fig. 10. 11). Can you guess what would happen if a potted plant is over watered? In this chapter you learnt Soil particles that respiration is a vital biological process. All living organisms need to respire to get the energy needed for the survival. Root hair Air space Fig.10.11 : Roots absorb air from the soil Aerobic respiration Diaphragm Inhalation Anaerobic respiration Exhalation Spiracles Breathing rate Gills Tracheae Cellular respiration Lungs Ribs What you have learnt ? Respiration is essential for survival of living organisms. It releases energy from the food. ? The oxygen we inhale is used to breakdown glucose into carbon dioxide and water. Energy is released in the process. ? The breakdown of glucose occurs in the cells of an organism (cellular respiration). ? If the food is broken down with the use of oxygen, it is called aerobic respiration. If the breakdown occurs without the use of oxygen, the respiration is called anaerobic respiration. ? During the heavy exercise when the supply of oxygen to our muscle cells is insufficient, food breakdown is by anaerobic respiration. ? Breathing is a part of the process of respiration during which an organisms takes in RESPIRATION IN ORGANISMS 135  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION the oxygen rich air and gives out air rich in carbon dioxide. The respiratory organs for the exchange of gases vary in different organisms. ? During inhalation, our lungs expand and then come back to the original state as the air moves out during exhalation. ? Increased physical activity enhances the rate of breathing. ? In animals like cow, buffalo, dog and cat the respiratory organs and the process of breathing are similar to those in humans. ? In earthworms, the exchange of gases occurs through the moist skin. In fishes it takes place through gills and in insects through the tracheae. ? In a plant the roots take in air present in the soil. Leaves have tiny pores called stomata through which they exchange gases. The breakdown of glucose in the plant cells is similar to that in other living beings. EXERCISES 1. Define cellular respiration. 2. Why does an athlete breathe faster and deeper than usual after finishing the race? 3. List the similarities and differences between aerobic and anaerobic respiration. 4. Why do we often sneeze when we inhale a lot of dust-laden air? 5. Take three test tubes. Fill ¾th of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test- tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2? 6. Tick mark ( ) the correct answer: (a) In cockroaches, air enters the body through (i) lungs (ii) gills (iii) spiracles (iv) skin (b) During heavy exercise, we get cramps in the legs due to the accumulation of (i) carbon dioxide (ii) lactic acid (iii) Alcohol (iv) water (c) Normal range of breathing rate per minute in an average adult person at rest is RESPIRATION IN ORGANISMS 136  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION (i) 9-12 (ii) 15-18 (iii) 21-24 (iv) 30-33 (d) During exhalation, the ribs (i) move outwards (ii) move downwards (iii) move upwards (iv) do not move at all 7. Match the items in column I with those in column II: Column I Column II (a) Yeast (i) Earthworm (b) Diaphragm (ii) Gills (c) Skin (iii) Alcohol (d) Leaves (iv) Chest Cavity (e) Fish (v) Stomata (f) Frog (vi) Lungs and skin (g) Cockroach (vii) Tracheae 8. Mark 'T' if the statement is true and 'F' if it is false: (i) During heavy exercise the breathing rate of a person slows down. (T/F) (ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F) (iii) Frogs breathe through their skin as well as their lungs. (T/F) (iv) The fishes have lungs for respiration. (T/F) (v) The size of the chest cavity increases during inhalation. (T/F) 9. Given below is a square of letters in which are hidden different words related to respiration in organisms. These words may be present in any direction upwards, downwards, or along the diagonals. Find the words for your respiratory system. Clues about those words are given below the square. RESPIRATION IN ORGANISMS 137  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION S V M P L U N G S C Z G Q W X N T L R M A T I D O T C I Y R X Y M S R A B R H I A N T A Y S T P T B Z R C E M I A M T S I H A S P I R A C L E S N E D K J N S A T (i) The air tubes of insects (ii) Skeletal structure surrounding chest cavity (iii) Muscular floor of the chest cavity (iv) Tiny pores on the surface of the leaf (v) Small openings on the sides of the body of an insect (vi) The respiratory organs of human beings (vii) The openings through which we inhale (viii) An anaerobic organism (ix) An organism with tracheal system 10. The mountaineers carry oxygen with them because: (a) At an altitude of more than 5 km there is no air. (b) The amount of air available to a person is less than that available on the ground. (c) The temperature of air is higher than on the ground. (d) The pressure of air is higher than that on the ground. RESPIRATION IN ORGANISMS 138  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION 11. Give two example of each of the following: (1) Animals that breathe through gills __________________ (2) Animals that breathe through spiracles __________________ (3) Animals that breathe through skin __________________ Extended Learning- Activities and Projects 1. Observe fish in an aquarium. You will find flap like structures on both sides of their heads. There are flaps which cover the gills. These flaps open and close alternately. On the basis of these observations, explain the process of respiration in the fish. 2. Visit a local doctor. Learn about the harmful effects of smoking. You can also collect material on this topic from other sources. You can seek help of your teacher or parents. Find out the percentage of people who smoke. If you have a smoker in your family, confront him with the material that you have collected. 3. Visit a doctor. Find out about artificial respirations.Ask the doctor. (a) When does a person need artificial respiration? (b) Does the person need to be kept on artificial respiration temporarily or permanently? (c) From where can the person get supply of oxygen for artificial respiration? 4. Measure the breathing rate of the members of your family and some of your friends. Investigate. (a) If the breathing rate of children is different from that of adults. (b) If the breathing rate of males is different from that of females. If there is a difference in any of those cases, try to find the reason. You can read more on the following website: www.health.howstuffworks.com/adam-200142.htm RESPIRATION IN ORGANISMS 139  JAMMU AND KASHMIR STATE BOARD OF SCHOOL EDUCATION DO YOU KNOW? For us oxygen is essential, but for those organisms which do not use it, oxygen is toxic. In fact, for humans and other organisms it may be dangerous to breathe pure oxygen for long. If we inhale CO (carbon monoxide) produced through incomplete combustion of coal, respiration gets blocked leading to death of an organism. At high altitude areas, the pressure of air decreases causing problem in inhalation. Thus, the people living there are adapted by having more no. of RBC as compared to those living in low altitude areas. RESPIRATION IN ORGANISMS 140