7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS

peanut Food has to be burnt to release energy. Does the food really burn in our body?

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS

BODY CELL oxygen food RESPIRATION B C A

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS We can summarise the process of respiration in a simple word equation. food oxygen carbon dioxide water++ + ENERGY Where does the oxygen required for respiration is obtained? How is it transported to the body cells?

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Gaseous exchange in plants XPERIMENT 7.18 (p.56) Materials and apparatus boiling tubes test tube rack thread hydrogencarbonate indicator aluminium foil 4 1 about 50 cm about 20 cm 3 2 stoppers table lamp green leaves

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS aluminium foil hydrogencarbonate indicator leaves ABCD 1.Set up the apparatus as shown in the diagram on the right.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Boiling tubeAt the beginningAfter 1 hour A B C D 2.Leave the boiling tubes in bright light for about one hour. Then record the colour of the indicator. Which tubes are used as the control? _______

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Gas A Gas B This exchange of oxygen and carbon dioxide is called gaseous exchange. Experiment 7.15 Do you know?

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Experiment 7.15 Step 1 : Tube B is a control experiment. Why? 207/ 207/

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Gaseous exchange in animals Animals obtain energy in a process called _______________. Animals take in _________ and give out _______ during breathing.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Gaseous exchange in plants

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Eric likes plants very much. His house is fully decorated with green plants. Activity 7 (e) Feeling dizzy in a plant house I like green plants very much. They make me healthy by providing me with a large amount of oxygen.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS One night, Eric slept in his house with all the windows closed. He felt dizzy in the next morning. What is the possible reason that makes Eric feel dizzy? Discuss with your classmates to find it out.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Gaseous exchange in plants XPERIMENT 7.18 Materials and apparatus boiling tubes test tube rack thread hydrogencarbonate indicator aluminium foil 4 1 about 50 cm about 20 cm 3 2 stoppers table lamp green leaves

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS aluminium foil hydrogencarbonate indicator leaves ABCD 1.Set up the apparatus as shown in the diagram on the right.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Boiling tubeAt the beginningAfter 1 hour A B C D 2.Leave the boiling tubes in bright light for about one hour. Then record the colour of the indicator. Which tubes are used as the control? _______

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS The table below shows the colours of hydrogencarbonate indicator in the presence of different concentrations of carbon dioxide. Concentration of carbon dioxide > 0.03% = 0.03% (normal air) < 0.03% Colour of the indicator yellowOrange redpurple

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Expt video 207/ 207/

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Explain the results in tube A. The leaf in tube A carries out both photosynthesis and respiration. The rate of _____________ is higher than that of __________. As _____________ needs carbon dioxide, the concentration of carbon dioxide in tube A is __________. The indicator turns __________.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Explain the results in tube B. As light is blocked by the aluminium foil, the leaf in tube B does not carry out ____________. It only carries out ____________, ____________ is given out and its concentration ___________ (increases / decreases). Then, the indicator turns _________.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Green plants can carry out photosynthesis : take in carbon dioxide and produce oxygen. Do green plants really release oxygen ALL the time Do green plants really release oxygen ALL the time Activity 7(e) Experiment 7.18

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS In day time, green plants carry out photosynthesis. photosynthesis carbon dioxide oxygen

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS green plants respire BOTH day and night. Remember that green plants respire BOTH day and night. oxygen carbon dioxide respiration

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS At night, photosynthesis stops(why?) and only respiration occurs. respiration oxygen carbon dioxide Gaseous exchange in green plants in the day time is ________from that at night.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS biology/greenplantsasorganisms/0photosy nthesisrev6.shtmlhttp:// biology/greenplantsasorganisms/0photosy nthesisrev6.shtml

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Under bright sunlightAt night photosynthesis > respiration carbon dioxide in air carbon dioxide oxygen respiration oxygen carbon dioxide Rate of photosynthesis Net uptake: Gas A Net release: Gas B Net uptake: Gas A Net release: Gas B

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS What have you learnt in this lesson? Under bright sunlight, there is a net uptake of _______and a net release of _________ by green plants. At night, green plants only release _______ and take in _________.

7.5 GASEOUS EXCHANGE IN ANIMALS AND PLANTS Homework w/b 2A P.11(part A 1, 2,4,5) P.13(1) P.15(B) P.17(1-5, 7) P.18-19(1-5) P.20(7) P.21-23(1,3,4) P.24(6)