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NCE features in this lesson Actvity ba...

NCE features in this lesson Actvity based Discovery based LearninR Learning. Class Dicussiorns.Digital Literacy. Peal life Situations " Higher Order Thirking "Strengthening Values 11 Respiration You have already read that energy is released * internal respiration or cellular respiration, from digested food through the process of 1.e. using oxygen to break down food to respiration. During this process, the nutrients release energy. Internal respiration occurs of the digested food react with oxygen in the in the body cells. body cells to release energy. The reaction with In respiration, glucOse molecules react Oxygen 1s known as oxidation. Respiration is with oxygen and break down into carbon the process of taking in oxygen, using it for dioxide and water to release energy. The release of energy by oxidation of food, and chemical reaction involved in respiration is eliminating the waste products-carbon dioxide summarized here: and water. 6C0, + 6H,0 + Energy C,H,0, glucose + 60, oxygen ’ carbon dioxide The two main processes of respiration are: water * external respiration or breathing, i.e. taking in air rich in oxygen (inhalation) RESPIRATION IN PLANTS and giving out air rich in carbon dioxide Since plants are living things, they also (exhalation). respire by taking in oxygen and giving out IN THIS CHAPTER RESPIRATION IN PLANTS RESPIRATION IN ANIMALS THE RESPIRATORY SYSTEM IN HUMANS TYPES OF RESPIRATION RESPIRATION I17  STOMATA GUARD CELL Fi6. 11.1 Stomata are small pores in leaves place. through which exchange of gases takes carbon dioxide. Plants do not have any organs for breathing. The exchange of FlG. 11.2 Aerial roots of mangroves onygen and carbon dioxide takes place through small pores called stomata (sinqular: stoma) dioxide and heat energy during respiration by Activities 1and 2. present in the leaves and stem. Stomata along wth its nearby guard cells and other cells are called the stomatal apparatus Root respiration (Fiq. 11.1). The expansion and contraction Root cells of plants also need oxygen to generate of quard cells, which occurs due to the supply energy. They get this oxygen from air trapped of moisture and light, results in opening between soilparticles. That is why we should not and closing of the stomata. The rate of overwater potted plants-the water replaces the exchange of gases in plants is much slower than air in the soil and the roots cannot breathe. This in animals. affects the growth of plants. Mangrove tres Some of the energy released during growing in swampy areas cannot get air from the espiration is used by the organism. The rest soil as it is waterlogged. They have aerial roots lost as heat. You can show release of carbon ke in air (Fig. 11.2).  FiG. 11.4 Heat is released during respiration. generate trapped photosynthesis and respiration Inplants, both photosynthesis spiracles on their bodies. Air. enters through ould not oCCr during theday. Since and respiration tnese openings and reaches all parts of the aces the he. This the major activity, more during photosynthesis photosynthesis xygen is than is absorbedreleased is Dody through respiratory tubes called trachea and their branches called tracheoles. trees, there is a net during respiration. Therefore om the of carbon dioxide and release of absorption Oxygen by CELL MEMBRANE roots plantsduring the day. CO, However, photosynthesis does not 0Ccur Amoeba on atnight. Only respiration takes place, which means that plants take in OXygen and release GILLS Fish MOIST SKIN carbon dioxide at night. in LUNGS RESPIRATION IN ANIMALS pifferent animals have different ways in which Frog the exchange of Oxygen and carbon dioxide Grasshopper OCCUrs in their bodies. Some of these ways are Co, discussed below(Fig. 11.5). MOIST Through cell membrane or skin: In unicellular 0. 0UTER Paramecium, SURFACE organisms, Such as Amoeba and diffusion exchange of gases takes place by SPIRACLE Earthworm and through the cell membrane. In Hydra place by takes place earthworm, exchange of gases takes FIG. 11.5 Exchange of gases MEMBRANE in Amoeba, surface. through GILLS in fish, CELL diffusion through the moist outer cockroaches, SPIRACLES in grasshopper, LUNGS AND MOIST SKIN in frog as Through air holes: Insects, such inearthworm. and MOIST OUTER SURFACE openings called grasshoppers, etc., have RESPIRATION 119  Through gills: Fishes use gills for exchange of gases Gills are made up of a large number AcrIvITY 3 (Experimental of filaments, richly supplied with thin blood veins called capillaries. As water through the mouth it flows over the gills. The blood in the enters tube A insert a wire gauze and put a on it, as shown investigation) Take two identical test tubes A and B. Pour a little ime water in each. In test beat and capillaries absorbs oxvgen (Fig. 11.6). Tightly gives out carbon dioxide walls. through its close the corks on both the tubes BEETLE Through lungs: Atadpole has into a frog it develops gills but as it to make them grows air airtight. Observe WIRE called lungs for gaseous bags GAUZE frogs have lungs they can exchange. Though the lime water through their moist skin, also breathe after 12 hours. just like In which tube Birds and mammals also earthworms. have did the lime LIME developed lungs where gaseous exchangehighly water turn milky? WATER place. takes Why? A B FiG. 11.6 ORAL QUESTIONS FOR CLASS 1. Respiration 2. Exchange of and breathing are the same. Do you agree? Give DISCUSSION gases for respiration reasons. of exchange of gases faster? occurs in both plantsand animals. 3. In which of these is the rate Exchange of gases in animals takes place in many ways. Name three. THE RESPIRATORY SYSTEM IN HUMANS The human secreted by the inner lining of the esponsible respiratory for system consists taking in oxygen for of organs becomes warm by the nose. The air nose. The mucous and blood circulating in the d releasing ich are the carbon dioxide and water respiration our nose trap dirt, dustthe hair present inside waste products formed vapour, particles and disease biration. The ), trachea nostrils (the passages in during he main (windpipe), bronchi and the organs of the lungs n (Fig. 11.7). respiratory system NOSTRILS ng in PHARYNX ing in of air EPIGLOTTIS rich in The oxygen called inhalation. Dur lungs air aroundintousour TRACHEA clean. require As the air which is is BRONCHUS e air we breathe moist, BRONCHIOLES usnostrils, in moistened it is in passes LUNGS present the nose. by the DIAPHRAGM Mucous is  qerms, and esitatory systemprevent We dothem om breathe through out not entetng get clean ait Ose Therefore, we mouth instead of ,N the nose, It should always an infection, will ptotet usbreathe om the lungs the nose or nasal oughthe pharynx or cavity, the ai passes Ln touotes and alveoi in indppe o trachea, The throat cavity to the the lngs (highly magnifed ie) 0 smaller tubes windpipe called the bronchi branches into podut of tespiation) exchange passes out of the blood chus). Each bronchus enters (singular: into aluns. intothe air sacs, hus, of gases taves place in the lungs. The blood takes the oxygen to all the cells the lungs of the body where it is used to get energy thelungs, each bronchus branches out into Iromfood. The carbon dioxide released by the aller tubes called bronchioles. At the end cells as waste qoes back into the blood and these tubes are tiny air sacs called alveoli is released into the air sacs of the lungs. It : -oular: alveolus) (Fig. 11.8). Each lung then breathed out byus, The giving out of air ains about 300 million alveoli! The air we ich in carbon dioxide is called exhalation. the in eventually reaches these air sacs. sacs are surrounded by blood vessels. The How air enters the lungs out en present in the air we breathe in, qoes lo understand what Causes air to go in and the blood contained in blood vessels. The of the lungs, let us perform a simple activity ndioxide present in the blood (as a waste (see Activity 4). AcrivITY 4 (Making a model): Mechanism of breathing through lungs Cwo thin balloons to the two arms of a glass Y-tube. Pass the AIR RUSHES OU1 be through one-hole rubber cork. Take a bell jat. Fix the cork jar as g with the Y-tube and balloons in the mouth of the bell nin figure 11.9. open rim of the base of e arubber sheet tightly around the balloons ell jar. Now pull the rubber sheet down. How do the they get filled up with air? Now leave the rubber sheet. e? Do WALL0ONS GET e balloons get deflated? represent the lungs and the BALLOONS DLfLATE this experiment, the balloons chest cavity. The rubber sheet represents the ar represents the muscle present in the chest cavity. agm, which is a sheet of f. 11.9Mechanism represents the trachea and its two wer part of the Y-tutbe of breathing in man the bronchi. down, the space in the bell jar pressure, air from rubber sheet is pulled to this reduction in en the pressure inside the bell jar reduces. Due spae in the bell jar decrease, es and the air sheet, the By relaxing the rubber ushed out and the balloos  AcrIvITY 5(Experimental exhaled and Carbon dioxide in Take two test tubes each of them halE filled with ime water. Using two-holed invesintihalgateid:on stoppers, glass tubes and clips, set up the apparatus as shown in Figure 11.11. Use the rubber tube at the middle to breathe in and out through the mouth. As you Surl in air through the rubber tube, open clip Xand close clip Y. The inhaled ait DIAPHRAGM BREATHING RREATHING OUT through lime water in test tube A. passe FrG. 11.10 How air goes in and out of the lungs ‘INHALE When you breathe in air, the diaphragm goes down, increasing the space in the chest CLIP Y cavity. The air from the atmosphere enters the OPEN CLOSED lungs and they expand. When you breathe out, the diaphragm moves up, decreasing the space in the chest cavity. This forces the air out of LIME WATER the lungs (Fig. 11.10). B When a person needs extra energy-for example, when he or she is running-the As you exhale through the rubber tube breathing becomes faster, supplying more open clip Yand close clip X. The exhaled air passes through the lime water in test tube B. Oxygen to the cells. This speeds up the breakdown of food, thus releasing more energy. EXHALE Cellular respiration CLIP X CLIP Y The blood takes the oxygen to all cells of CLOSED OPEN the body. Blood has a substance called haemoglobin, which binds itself with oxygen to form oxyhaemoglobin. It is in this form that Oxygen is carried through the blood. Cellular LIME WATER respiration occurs in the cells. During cellular B FIG. 11.11 To show that exhaled air has ITS A FACT! more carbon dioxide than inhaled air The pharynx actually has two apertures-one In which test tube does the lime water opening into the windpijpe and the other into turn more milky? What does this show? the oesophagus. The aperture opening into the windpipe is guarded by a flap-ike structure OXYGEN 21% OXYGEN 16.4% called the epiglottis. It cdoses the windpipe when CARBON DIOXIDE 0.04% LUNGS CARBON DIOXIDE 4.4% youswallow food, so that the food partices Inhaled air Exhaled air donot enter it. If food or water ever enters the windpipe, you cough it out. This is the body's FiG. 11.12 Average composition of method of removing the food or water from it. inhaled and exhaled air  someAcTItime. for VITY 6 (Experimentat still St ting? Do some hght Measure your investigation): Rate of breathing there a exercise breat (ike hiwal ngking for Howa many breathsagainper measure rate. minute id you tae measure percept your ible difference? Now minute and your breathing ate when you exercise? breathing rate. What do heavy do you exercise like running for find? Why do you think you breathe at higher espiration the sugar to form carbon moleculesin food are Thedioxide and water, and aerobic respiration, Here, food in the form of Arergy given out. is place in the presence of oxygen. This is calied Oationis as follows: reaction involved in glucose is oxidized to produce carbon dioxide 60 6CO,dioxide and water. In the process, energy is released. Oxygen carbon 6H,0 + energy Aerobic respiration is carried out in almost all water This is similar to plants and animals. chemical the Some organisms such as yeast and some nat occurs during burning or reaction bacteria can live without oxygen. In their Owever, the two ch other processes (Table combust differ ion. from 11.1). Further, Table 11.2 cells, gluCOse is broken into alcohol and carbon ferentiates dioxide without using oxygen, to give energy spiration. between breathing and cellular Ihis process is called anaerobic respiration. Ihe amount of energy given out in anaerobic The carbon dioxide is respiration is much less than in aerobic respiration. lungs through the blood.transported back to ITS A FACT! TYPES OF RESPIRATION Yeast is a unicellular organism that respires anaerobically to yield alcohol. Yeast is theretore have studied about respiration that takes used to make beer and wine. TABLE 11,1 Differences between combustion and cellular PARAMETER respiration COMBUSTION CELLULAR RESPIRATION ce Combustion is a fast process. Cellular respiration is a slow process. nperature It occurS at high ce It can ocCur temperature. It occurs at body temperature. anywhere. It occurs only in living cells. rgy Energy is released in a single step in Energy is released in steps, and the form of heat and light. stored in chemical molecules called ATP. TABLE 11.2 Differences between breathing and cellular respiration AMETER BREATHING CELLULAR RESPIRATION e of process It is a physical process of exchange of Chemical reaction of oxidation of food gases. No chemical reaction takes place. takes place. It takes place outside the cells. It takes place within the cells. There is no release of energy. There is release of energy.  5. 4. acid tothis hich (rlluar What 3. 2. 1 Oxygen In proinduce respirationenergy. get SUch process, that, carbon WeWhat turn the from of onrespiration pres human, the enough lo Somet long as im es inheend lime the Did water a dipSnowh dissolving one The ONIdissolve Y is body lact ic ocCur s ge t the mi about lky? cool(oming to Wat er dissolved someBoll Kurs carried the causes there th di onygen e sta nce spicalrelsy, Conclude flask watsoler ution tyoeu mpeature in in anaerobireyeast di onide hol e d layer thin Put a to When Arvry exchange acid. is The notice bath lime t ig opper. thein oiof Mask qlu inSeal can during the to Thpar e tia l wiaddithintional duri n g the inthat B? g as in l A ose water tontact theorygen walerfor occur ORAL mUscular ruto nning, the isthe fabubbl in if at 1113) es about water Insert watprevents layer in has 7 or cellular bygases cells of accumul a ti o n your breakdoun produce stryourenuous absence yeast therefore test st necessary in A of 25C taken each a(loteorygen ol er, of earh tooled, with (Esperimental flask in ular even the QUESTI O NS cramps. muscl eener g y, of in tube? and inflask thin on Mask open aiprevent t, Malf it 15 to minutes without respiration? blo od. ocurs the body oxygen. flask car b on Di d col passing o urless by a each and fl --is of of anaer cells. obircequired putting test and glass in water Add oxygen. in In the FOR That la ct gl ic u cos e act cannot ivity A dio xi d e. th e tu be. flask a ir in thve the the nremon to allow Investigation):tw what lungs. In This produced lim e througn gas the let tube its (of with trom each yeat eal the r fatks wate proves water escaping Mainta and fhask from with theal What form InCLASS hence of of of bath. is lasks other shape a hask you oxygen. blood maBotshag1ngexercise. why aster a is iswhich lactic thit WATGLUCOS ER E ess? such oxygen DISCUSsiON part get acid This in the the You you Fls. Anserobe respiration to these respiration 11.13 carbonresults body affectedSometcangeitmes carried of relief the inlungs from activities leading relief in To Flask B Flast A respiration called? the cramps.dioxide in part from have demons ivingtrate blood? does completincreased e imto prove by or cramps organisms in take it and these anaerobir ing having after place? watbreerakdoun , circulatine cramps organ and suply hean a