How To Test Your Knowledge Of Anaerobic Respiration

Transcription

1 Teaching notes This resource is the perfect introduction to respiration in which students discover aerobic and anaerobic respiration for themselves through a series of straightforward activities. This activity is aimed at high ability students. The activities are arranged as a circus of eight stations around the room. There is a worksheet which students should fill in as they visit each station. The answers could be provided at each station in an envelope or back to back with the activity sheet in a plastic wallet. Equipment required Station 2 - beaker of respiring yeast Station 3 - models of generalised animal and plant cells Station 6 The experiment needs to be set up as a dummy so that students can predict the results. 4 test-tubes set up as below, but with pink coloured water in place of the indicator solution. Station 7 - flasks with boiled and germinating peas set up as diagram below. Or something to suggest a similar experiment e.g. two bunged opaque flasks, with thermometers one containing hot water, and the other containing room temp water. Station 8 - test-tubes of limewater with straws, one for each student Page 1 of 18

2 Respiration in cells can take place aerobically or anaerobically. The energy released is used in a variety of ways. Visit the stations around the room to complete this worksheet. Equation for aerobic respiration... Equation for anaerobic respiration in animals (used to obtain energy if insufficient oxygen is reaching the muscles for aerobic respiration)... Equation for anaerobic respiration in organisms such as yeast... Station 1: Which types of athletic events require anaerobic respiration? What is the downside? Station 2: Why will anaerobic respiration eventually kill yeast? What do we use the products of respiration in anaerobic yeast for? Can you name other food products that utilise anaerobic respiration? Page 2 of 18

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4 Station 3: Name the structures used in respiration in animal and plant cells... Station 4: To prevent lactic acid build up, endurance athletes limit their heart rate to prevent anaerobic respiration. To stay below the lactic acid threshold (the point where blood lactic acid concentration starts to rise) Jude s maximum heart rate needs to be:.. Station 5: During an aerobics class, what would happen to your body temperature and breathing rate? Why? Aerobic respiration is a series of reactions which can summarised by this equation. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (+ energy released) glucose oxygen carbon dioxide water Does the above equation look familiar which other process does it remind you of? Page 4 of 18

5 Station 6: Hydrogencarbonate indicator is pink. It turns yellow if CO 2 is added and purple if CO 2 is removed. Colour the indicator in each tube to show the results you would expect to see after 1 hour. Why does the 3 rd tube have foil around it? What is the purpose of the 4 th tube? Station 7: Which results are for which flask? How do you know? Time (hours) Temperature ( C) Flask Flask Page 5 of 18

6 Station 8: Limewater turns cloudy in the presence of CO 2 When I breathed into limewater it turned... this proves that my exhaled air contains... so I am respiring. Extension tasks: As the breakdown of glucose is incomplete in anaerobic respiration, much less energy is released than during aerobic respiration. Research the difference in energy released per gram of glucose used. Anaerobic respiration results in an oxygen debt what does this mean? Page 6 of 18

7 Station 1 information sheet Anaerobic respiration glucose lactic acid (+energy released) incomplete breakdown of glucose Discuss the following questions in your pairs and then fill in your answers on your sheet. Which types of athletic events require anaerobic respiration? What is the downside to this form of respiration? Page 7 of 18

8 Station 1 answer sheet Anaerobic respiration occurs during high-intensity activities e.g. sprinting If muscles are subjected to long periods of vigorous activity they become fatigued, i.e. they stop contracting efficiently. One cause of muscle fatigue is the build-up of lactic acid in the muscles which causes cramps. Blood flowing through the muscles removes the lactic acid Page 8 of 18

9 Station 2 information sheet 1 Yeast cells respire anaerobically producing ethanol and carbon dioxide: glucose ethanol + carbon dioxide (+energy released) Discuss the following questions in your pairs and then fill in your answers on your sheet. This will eventually kill the yeast? Why? What do we use the products of this type of respiration for? Can you name other food products that utilise anaerobic respiration? 1 Yeast cells/ Credit: SciMAT / Photo Researchers / Universal Images Group/ Copyright Photo Researchers / For Education Use Only. This and millions of other educational images are available through Britannica Image Quest. For a free trial, please visit Page 9 of 18

10 Station 2 answer sheet glucose ethanol + CO 2 (+ energy released) Yeast cells respire anaerobically eventually the ethanol build-up will become toxic to the yeast. Ethanol is used to make alcoholic drinks CO 2 is used to make bread rise All of these food products utilise anaerobic respiration yoghurt, cheese, vinegar Page 10 of 18

11 Station 3 information sheet Where enzymes are made. Location of reactions in anaerobic respiration Holds genetic code for enzymes involved in respiration Contains the enzymes for aerobic respiration. Allows gases and water to pass freely into and out of the cell. Controls the passage of other molecules. Name the structures used in respiration in plant and animal cells. Station 3 answer sheet Most of the reactions in aerobic respiration take place inside mitochondria Page 11 of 18

12 Station 4 information sheet Anaerobic respiration is essential for short bursts of energy but cannot be used for longer periods. Endurance athletes need to pace themselves to avoid anaerobic respiration. A build-up of lactic acid would hinder their performance. Jude should keep her heart rate just below the lactic acid threshold (the point where her blood lactic acid conc. starts to rise) when she trains. What should her maximum heart rate be? Station 4 answer sheet Maximum heart rate should be somewhere between 155 and 165 beats per minute Page 12 of 18

13 Station 5 During an aerobics class, what would happen to your body temperature, heart rate and rate and depth of breathing? Why? Aerobic respiration is a series of reactions which can summarised by this equation. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (+ energy released) glucose oxygen carbon dioxide water Does the above equation look familiar? Station 5 answer sheet During an aerobics class, what would happen to your body temperature, heart rate and rate and depth of breathing? Why? They would all increase. These changes increase the blood flow to the muscles and so increase the supply of sugar and oxygen and increase the rate of removal of carbon dioxide. Heat is a by-product of respiration. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (+ energy released) glucose oxygen carbon dioxide water The equation for aerobic respiration (above) is the reverse of the equation for photosynthesis (below). 6CO 2 + 6H 2 O light energy C 6 H 12 O 6 + 6O Page 13 of 18

14 Station 6 Hydrogencarbonate indicator is pink. It turns yellow if CO 2 is added and purple if CO 2 is removed. Discuss the following questions in your pairs and then fill in your answers on your sheet. Predict the colour of the 4 tubes. Why does the 3rd tube have foil around it? What is the purpose of the 4th tube? Page 14 of 18

15 Station 6 answers Predict the colour of the 4 tubes see below Why does the pondweed tube have foil around it? This prevents the pondweed from photosynthesising. Depending upon the rate of photosynthesis vs. respiration the indicator could be pink, yellow or purple! What is the purpose of the 4th tube? Control Page 15 of 18

16 Station 7 Susan set up the apparatus as shown. Both sets of peas were sterilised to kill microbes on their surfaces. She measured the temperature inside each flask every 12 hours. Her results are shown in the table below, but she forgot to label her table. Which results are for which flask? How do you know? Time (hours) Flask? Temperature ( C) Flask? Page 16 of 18

17 Station 7 answer sheet Time (hours) Flask B Boiled peas Temperature ( C) Flask A Peas soaked in water The peas are in flask A respiring and respiration produces heat. The peas in flask B were dead (had been boiled) so could not respire and release heat energy Page 17 of 18

18 Station 8 The test-tubes contain limewater which turns cloudy in the presence of CO 2 Breathe out gently into the straw. Health and safety - DO NOT SUCK UP THROUGH THE STRAW. You may need breathe out several times to cause a change. What happens? Does this show you are respiring aerobically or an anaerobically? Health and safety - Remove the straw when you have finished to show the test tube has been used. Station 8 answers When you breathed into the limewater it should have turned cloudy a positive test for carbon dioxide. The presence of CO2 in your exhaled air proves you are respiring aerobically. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O (+ energy released) glucose oxygen carbon dioxide water Anaerobic respiration in animals no carbon dioxide is produced. glucose lactic acid (+ energy released) Page 18 of 18