S 3 BGE L 3 5 Biology Part
S 3 BGE L 3 -5 Biology Part 2 Photosynthesis 2 C-G: Investigating Photosynthesis Lesson 1: Investigating the production of starch 10/24/2020 Mrs Smith – S 3 BGE Biology 1
National 5 Biology Lesson 1 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 3&4 Learning Outcomes: You should be able to… o o Know and prove that glucose is stored as starch. Test a leaf for starch to prove its presence. Describe why each stage is performed when testing a leaf for starch. 10/24/2020 what happens to iodine solution Mrs Smith – S 3 BGE Biology State in the presence of starch 2
STARTER LESSON: Complete the word wheel. Write the keywords in a short paragraph but they must be in the order of the word wheel (start at photosynthesis). Photosynthesis Starch Chloroplasts 10/24/2020 Glucose Extension – Can you incorporate the word equation and describe how gases enter and leave the leaf Light Energy Mrs Smith – S 3 BGE Biology 3
S 3 BGE L 3 -5 Biology Revision On a SMB write down the photosynthesis word equation 10/24/2020 Mrs Smith – S 3 BGE Biology 4
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation today we are going to test a leaf to prove that starch is stored during photosynthesis 10/24/2020 Mrs Smith – S 3 BGE Biology 5
Glucose molecules produced during photosynthesis are stored as starch • When plants store their food, they join glucose molecules together to form long chains called starch. • Plant leaves don’t normally contain much glucose because they use it straight away (that is why it’s more difficult to test for glucose). • Any leftover they store as starch. We can test a leaf for starch using iodine solution 10/24/2020 Mrs Smith – S 3 BGE Biology 6
Iodine solution is the test for starch • If there is NO starch present. The iodine will not change it will stay brown. • If there IS starch present the starch will turn blue/black • This will happen to potato or bread because there is lots of starch (carbohydrate) in them. • Iodine won’t change if we test sugar. As there is no starch. • We can do it to a leaf BUT. . We need t release the starch that is deep inside the leaf in the chloroplasts. 10/24/2020 Mrs Smith – S 3 BGE Biology 7
Testing a leaf for starch – Method by diagram AIM: To investigate if starch is stored during photosynthesis 1) Cut out leaf disc with cork borer 2) Put leaf disc in boiling water for 1 min (to burst cell membrane) 3)Turn Bunsen off. Pick out disc with forceps. Place in test tube half filled with ethanol. Place test tube back in beaker. 10/24/2020 Mrs Smith – S 3 BGE Biology 4) Put leaf disc in warm water (to soften it) 5) Transfer disc to dimple tile. Add few drops of iodine (test for starch) 6) Rinse disc with cold water (to remove excess iodine) 8
Testing a leaf for starch – Written Method 1. Half fill beaker with water and heat with Bunsen burner 2. Cut out 1 leaf disc with cork borer 3. Transfer leaf disc into beaker of boiling water for 1 min (to burst cell membrane). 4. Turn Bunsen burner off after 1 minute (this is essential as ethanol is very flammable). 5. Now ¼ fill tube with ethanol (to burst open the chloroplast – the alcohol will turn green whilst the leaf becomes white). 6. Transfer leaf disc into tube of alcohol with tweezers 7. Take disc out with tweezers and place back in beaker of warm water (to soften it). 8. Now transfer disc with tweezers to dimple tile. 10/24/2020 Mrs Smith – S 3 BGE Biology 9. Add a few drops of iodine and look for colour change. AIM: To investigate if starch is stored during photosynthesis 9
Testing a leaf for starch – Method Results and Conclusion AIM: To investigate if starch is stored during photosynthesis 10/24/2020 Results: The iodine solution turned from brown to blue black, as seen in the photo opposite. Conclusion: As iodine solution has had a positive result for starch (it changed from brown to blue/black), it can be concluded that starch is stored during photosynthesis. Mrs Smith – S 3 BGE Biology 10
Plenary: 10/24/2020 Mrs Smith – S 3 BGE Biology 11
Plenary: How did you? 10/24/2020 Mrs Smith – S 3 BGE Biology 12
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe that glucose is stored as starch. o Test a leaf for starch to prove its presence. o Describe why each stage is performed when testing a leaf for starch. o State what happens to iodine solution in the presence of starch 10/24/2020 Mrs Smith – S 3 BGE Biology 13
S 3 BGE L 3 -5 Biology Part 2 Photosynthesis 2 C-G: Investigating Photosynthesis Lesson 2: Investigating that light is essential for photosynthesis 10/24/2020 Mrs Smith – S 3 BGE Biology 14
National 5 Biology Lesson 2 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 3&4 Learning Outcomes: You should be able to… o Describe the process of testing a leaf for starch. Specifically why each stage is performed o Explain that light is essential for photosynthesis to take place o Describe an experiment to prove that light is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 15
STARTER: SELF-EVALUATION TASK: Complete your record sheet – remember if you are red or amber you must consider how to fill in your LEARNING GAPS 10/24/2020 Mrs Smith – S 3 BGE Biology 16
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation. We have proven that glucose is stored as starch. Today we are going to test a leaf to prove that light is essential for photosynthesis to occur. 10/24/2020 Mrs Smith – S 3 BGE Biology 17
S 3 BGE L 3 -5 Biology Can you think how we could prove that light is essential for photosynthesis? • We can show that a plant needs light, carbon dioxide and chlorophyll for photosynthesis. • This is done by removing one of these factors from the plant and then test to see if the plant has been able to produce starch. For light we can either • Take a potted plant and de-starch it by keeping it in darkness for 24 hours or…… • Attach a piece of metal foil or paper on both sides of a leaf and leave it for 24 -48 hrs). 10/24/2020 Mrs Smith – S 3 BGE Biology 18
Testing a leaf for starch – Method by diagram AIM: To investigate if light is essential for photosynthesis 1) Cut out 2 pieces of leaf. A square one from plant kept in the dark, a triangle from one exposed to sunlight (the control) 2) Put both leaves in boiling water for 1 min (to burst cell membrane) 3)Turn Bunsen off. Pick out the leaf shapes with forceps. Place in test tube half filled with ethanol. Place test tube back in beaker. 10/24/2020 Mrs Smith – S 3 BGE Biology 4) Put leaf shapes in warm water (to soften them) 5) Transfer leaf shapes to dimple tile. Add few drops of iodine (test for starch) 6) Rinse leaf shapes with cold water (to remove excess iodine) 19
Testing a leaf for starch – Written Method 1. Half fill beaker with water and heat with Bunsen burner 2. Cut out 2 pieces of leaf. A square one from plant kept in the dark, a triangle from one exposed to sunlight (the control) 3. Transfer leaf discs into beaker of boiling water for 1 min (to burst cell membrane). AIM: To investigate if light is essential for photosynthesis 4. Turn Bunsen burner off after 1 minute (this is essential as ethanol is very flammable). 5. Now ¼ fill tube with ethanol (to burst open the chloroplasts – the alcohol will turn green whilst the leaves becomes white). 6. Transfer leaf discs into the tube of alcohol with tweezers 7. Take discs out with tweezers and place back in beaker of warm water (to soften it). 8. Now transfer discs with tweezers to dimple tile. 9. Add a few drops of iodine , leave a few minutes to develop, rinse with cold water 10/24/2020 Mrs Smith – S 3 BGE Biology 20 to remove excess iodine solution and look for colour change.
Testing a leaf for starch – Method Results and Conclusion Results: • AIM: To investigate if light • is essential for photosynthesis The iodine solution turned from brown to blue/black for the leaf exposed to direct sunlight, as seen in the photo below. The iodine solution did not change colour for the leaf taken from plant which was de-starched by placing in a dark cupboard for 24 hrs. Conclusion: Leaf left in the dark 10/24/2020 Leaf exposed to light • As iodine solution has had a negative result for starch only in leaf kept in the dark. It can be concluded that light is essential for glucose to be stored as starch during photosynthesis. • We know the result is true as the control (the plant was given light) produced starch as expected and had a positive result for starch (iodine turned blue/black) Mrs Smith – S 3 BGE Biology 21
Plenary: Complete the worksheet 10/24/2020 Mrs Smith – S 3 BGE Biology 22
Plenary: How did you do? 10/24/2020 Mrs Smith – S 3 BGE Biology 23
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe the process of photosynthesis. o State that glucose is stored as starch o Describe the process of testing a leaf for starch. Specifically why each stage is performed o Explain that light is essential for photosynthesis to take place o Describe an experiment to prove that light is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 24
S 3 BGE L 3 -5 Biology Part 2 Photosynthesis 2 C-G: Investigating Photosynthesis Lesson 3: Investigating that carbon dioxide is essential for photosynthesis to take place 10/24/2020 Mrs Smith – S 3 BGE Biology 25
National 5 Biology Lesson 3 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 3&4 Learning Outcomes: You should be able to… o o Describe the process of testing a leaf for starch. Specifically why each stage is performed! Explain that light is essential for photosynthesis to take place Explain that Carbon dioxide is essential for photosynthesis to take place Describe an experiment to prove that carbon dioxide is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 26
What do you think? Are they right? STARTER: The reason grass doesn't need to be cut in the winter is that the grass doesn’t grow then as there is no sunlight The plant will grow better on a sunny day compared to a cloudy one The plant won’t grow at all if the sky is cloudy
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation. We have proven that glucose is stored as starch and that light is essential. Today we are going to test a leaf to prove that carbon dioxide is essential for photosynthesis to occur. 10/24/2020 Mrs Smith – S 3 BGE Biology 28
S 3 BGE L 3 -5 Biology Can you think how we could prove that light is essential for photosynthesis? • We can show that a plant needs light, carbon dioxide and chlorophyll for photosynthesis. • This is done by removing one of these factors from the plant and then test to see if the plant has been able to produce starch. For carbon dioxide we can either • Take a potted plant and de-starch it by covering it with a Bell Jar containing sodium hydroxide and leave it for 24 -48 hrs. • Or do the same using a clear plastic bag which is tightly ties to prevent air form entering 10/24/2020 Mrs Smith – S 3 BGE Biology 29
Testing a leaf for starch – Method by diagram AIM: To investigate if carbon dioxide is essential for photosynthesis 1) Cut out 2 pieces of leaf. A square one from plant deprived of CO 2, a triangle from one exposed to CO 2 (the control) 2) Put both leaves in boiling water for 1 min (to burst cell membrane) 3)Turn Bunsen off. Pick out the leaf shapes with forceps. Place in test tube half filled with ethanol. Place test tube back in beaker. 10/24/2020 Mrs Smith – S 3 BGE Biology 4) Put leaf shapes in warm water (to soften them) 5) Transfer leaf shapes to dimple tile. Add few drops of iodine (test for starch) 6) Rinse leaf shapes with cold water (to remove excess iodine) 30
Testing a leaf for starch – Written Method 1. Half fill beaker with water and heat with Bunsen burner 2. Cut out 2 pieces of leaf. A square AIM: To one from plant deprived of CO 2, a triangle from one investigate if exposed to CO 2 (the control). carbon dioxide is 3. Transfer leaf discs into beaker of boiling water for 1 min (to essential for burst cell membrane). photosynthesis 4. Turn Bunsen burner off after 1 minute (this is essential as ethanol is very flammable). 5. Now ¼ fill tube with ethanol (to burst open the chloroplasts – the alcohol will turn green whilst the leaves becomes white). 6. Transfer leaf discs into the tube of alcohol with tweezers 7. Take discs out with tweezers and place back in beaker of warm water (to soften it). 8. Now transfer discs with tweezers to dimple tile. 9. Add a few drops of iodine , leave a few minutes to develop, rinse with cold water 10/24/2020 Mrs Smith – S 3 BGE Biology 31 to remove excess iodine solution and look for colour change.
Testing a leaf for starch – Method Results and Conclusion AIM: To investigate if carbon dioxide is essential for photosynthesis Results: • • The iodine solution turned from brown to blue/black for the leaf exposed to normal air (containing carbon dioxide), as shown in the photo below. The iodine solution did not change colour for the leaf deprived of carbon dioxide by using sodium hydroxide for 24 hrs. Conclusion: Leaf deprived of carbon dioxide 10/24/2020 Leaf exposed to carbon dioxide • As iodine solution has had a negative result for starch deprived of carbon dioxide. It can be concluded that carbon dioxide is essential for glucose to be stored as starch during photosynthesis. • We know the result is true as the control (the plant exposed to normal air containing carbon dioxide) produced starch as expected and had a positive result for starch (iodine turned Mrs Sm. ith – S 3 BGE Biology 32 blue/black)
Plenary: How would you teach it PHOTO…WHAT? ? ? If you were going to teach this lesson to an alien from outer space, what would you identify as the key things they would need to know? 10/24/2020 Mrs Smith – S 3 BGE Biology 33
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe the process of testing a leaf for starch. Specifically why each stage is performed! o Explain that light is essential for photosynthesis to take place o Explain that Carbon dioxide is essential for photosynthesis to take place o Describe an experiment to prove that carbon dioxide is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 34
National 5 Biology Lesson 4 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 3&4 Learning Outcomes: You should be able to… o o Describe the process of testing a leaf for starch. Specifically why each stage is performed! Explain that light and carbon dioxide is essential for photosynthesis to take place Explain that water is also is essential for photosynthesis to take place Describe an experiment to prove that water is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 35
Photosynthesis and leaf adaptions Match and Draw STARTER:
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation. We have proven that glucose is stored as starch & that light and carbon dioxide is essential. Today we are going to test a leaf to prove that water is essential for photosynthesis to occur. 10/24/2020 Mrs Smith – S 3 BGE Biology 37
S 3 BGE L 3 -5 Biology Can you think how we could prove that water is essential for photosynthesis? • We can show that a plant needs light, carbon dioxide, water and chlorophyll for photosynthesis. • This is done by removing one of these factors from the plant and then test to see if the plant has been able to produce starch. For water we can • Take a potted plant deprive it from water (48 -72 hrs or until the soil is extremely dry). • The control for this experiment will receive water 10/24/2020 Mrs Smith – S 3 BGE Biology 38
Testing a leaf for starch – Method by diagram AIM: To investigate if water is essential for photosynthesis 1) Cut out 2 pieces of leaf. A square one from plant deprived of water, a triangle from one given water (the control) 2) Put both leaves in boiling water for 1 min (to burst cell membrane) 3)Turn Bunsen off. Pick out the leaf shapes with forceps. Place in test tube half filled with ethanol. Place test tube back in beaker. 10/24/2020 Mrs Smith – S 3 BGE Biology 4) Put leaf shapes in warm water (to soften them) 5) Transfer leaf shapes to dimple tile. Add few drops of iodine (test for starch) 6) Rinse leaf shapes with cold water (to remove excess iodine) 39
Testing a leaf for starch – Written Method 1. Half fill beaker with water and heat with Bunsen burner 2. Cut out 2 pieces of leaf. A square AIM: To one from plant deprived of water, a triangle from one investigate if exposed to given water (the control). water is essential 3. Transfer leaf discs into beaker of boiling water for 1 min (to for burst cell membrane). photosynthesis 4. Turn Bunsen burner off after 1 minute (this is essential as ethanol is very flammable). 5. Now ¼ fill tube with ethanol (to burst open the chloroplasts – the alcohol will turn green whilst the leaves becomes white). 6. Transfer leaf discs into the tube of alcohol with tweezers 7. Take discs out with tweezers and place back in beaker of warm water (to soften it). 8. Now transfer discs with tweezers to dimple tile. 9. Add a few drops of iodine , leave a few minutes to develop, rinse with cold water 10/24/2020 Mrs Smith – S 3 BGE Biology 40 to remove excess iodine solution and look for colour change.
Testing a leaf for starch – Method Results and Conclusion Results: AIM: To • investigate if water is essential • for photosynthesis Leaf deprived of water 10/24/2020 Leaf given water The iodine solution turned from brown to blue/black for the leaf given water as shown in the photo below. The iodine solution did not change colour for the leaf deprived of water for 48 -72 hrs. Conclusion: • As iodine solution has had a negative result for starch deprived of water. It can be concluded that water is essential for glucose to be stored as starch during photosynthesis. • We know the result is true as the control (the plant given water produced starch as expected and had a positive result for starch (iodine turned blue/black) Mrs Smith – S 3 BGE Biology 41
Plenary: Can you write instructions! 2019 Write detailed instructions how to carry out an experiment to prove that water is essential for photosynthesis. 10/24/2020 Mrs Smith – S 3 BGE Biology EDITION 42
Plenary: How did you do…peer assessment • • Pass your detailed instructions to your shoulder partner. As a peer assessor you should complete the form and pass it back to your partner 10/24/2020 Mrs Smith – S 3 BGE Biology 43
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe the process of testing a leaf for starch. Specifically why each stage is performed! o Explain that light and carbon dioxide is essential for photosynthesis to take place o Explain that water is also is essential for photosynthesis to take place o Describe an experiment to prove that water is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 44
National 5 Biology Lesson 5 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 5 Learning Outcomes: You should be able to… o o Describe the process of testing a leaf for starch. Specifically why each stage is performed! Explain that light, carbon dioxide and water are essential for photosynthesis to take place Explain that chlorophyll is also is essential for photosynthesis to take place Describe an experiment to prove that chlorophyll is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 45
Complete a spider diagram to summarise your learning for investigating photosynthesis? STARTER: Investigating photosynthesis
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation. We have proven that glucose is stored as starch & that light, water and carbon dioxide are essential. Today we are going to test a leaf to prove that chloroplasts (containing chlorophyll) are 10/24/2020 Mrs Smith – S 3 BGE Biology essential for photosynthesis to occur. 47
S 3 BGE L 3 -5 Biology Can you think how we could prove that light is essential for photosynthesis? • We can show that a plant needs light, carbon dioxide, water and chlorophyll for photosynthesis. • This is done by removing one of these factors from the plant and then testing to see if the plant has been able to produce starch. For chlorophyll we can • Use a variegated leaf. This means it is two colours (here the colours are white and green). • This is useful because we know that chlorophyll the green pigment found in chloroplasts gives a plant the green colour. • But what about the white parts, do they have any chlorophyll? ? Can they photosynthesise? 10/24/2020 Mrs Smith – S 3 BGE Biology 48
Testing a leaf for starch – Method by diagram AIM: To investigate if chlorophyll is for photosynthesis 1) Take a variegated leaf 2) Put the leaf in boiling water for 1 min (to burst cell membrane) 3)Turn Bunsen off. Pick out the leaf with forceps. Place in test tube half filled with ethanol. Place test tube back in beaker. 10/24/2020 Mrs Smith – S 3 BGE Biology 4) Put the leaf in warm water (to soften them) 5) Transfer leaf to dimple tile. Add few drops of iodine (test for starch) 6) Rinse leaf with cold water (to remove excess iodine) 49
Testing a leaf for starch – Written Method 1. Half fill beaker with water and heat with Bunsen burner 2. Cut out 2 pieces of leaf. A square one from plant deprived of water, a triangle from one exposed to given water (the control). 3. Transfer leaf discs into beaker of boiling water for 1 min (to burst cell membrane). AIM: To investigate if chlorophyll is essential for photosynthesis 4. Turn Bunsen burner off after 1 minute (this is essential as ethanol is very flammable). 5. Now ¼ fill tube with ethanol (to burst open the chloroplasts – the alcohol will turn green whilst the leaves becomes white). 6. Transfer leaf discs into the tube of alcohol with tweezers 7. Take discs out with tweezers and place back in beaker of warm water (to soften it). 8. Now transfer discs with tweezers to dimple tile. 9. Add a few drops of iodine , leave a few minutes to develop, rinse with cold water 10/24/2020 Mrs Smith – S 3 BGE Biology 50 to remove excess iodine solution and look for colour change.
Testing a leaf for starch – Method Results and Conclusion AIM: To investigate if chlorophyll is essential for photosynthesis Results: • • The iodine solution turned from brown to blue/black only on the green parts (containing chloroplasts hence chlorophyll) of the leaf as shown in the photo below. The iodine solution did not change colour for the white parts of the leaf. Conclusion: • As iodine solution has had a negative result for starch on the white parts of the leaf, and a positive result for starch on the green parts of the plant. It can be concluded that chloroplasts (containing chlorophyll) are essential to produce glucose to be stored as starch during photosynthesis. 10/24/2020 Mrs Smith – S 3 BGE Biology 51
Plenary: 5 -5 -1 10/24/2020 Mrs Smith – S 3 BGE Biology 52
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe the process of testing a leaf for starch. Specifically why each stage is performed! o Explain that light, carbon dioxide and water are essential for photosynthesis to take place o Explain that chlorophyll is also is essential for photosynthesis to take place o Describe an experiment to prove that chlorophyll is essential for photosynthesis to take place. 10/24/2020 Mrs Smith – S 3 BGE Biology 53
National 5 Biology Lesson 6 : Benchmarks and Learning Intentions Level 3 Planet Earth: Biodiversity & interdependence SCN 3 -02 a; Topical Science SCN 3 -20 b National 3: Unit 1: Key Area 1. 4 – The process of photosynthesis Investigate the production of starch in leaves under different conditions, Level 4 Planet Earth: Biodiversity and interdependence SCN 4 -02 a; Topical Science SCN 4 -20 a National 4: Unit 1: Key Area 1. 6 The effect of limiting factors on photosynthesis. 1. 6 a Carry out starch tests on plants in various conditions 1. 6 b Use Elodea to find out about limiting factors L 7 Learning Outcomes: You should be able to… o Describe the process of testing a leaf for starch. Specifically why each stage is performed! o Explain that water, carbon dioxide, light and chlorophyll are essential for photosynthesis to take place. (you should be able to describe what experiment will prove each of these!) o Describe an experiment to prove that oxygen is releases as a by-product of photosynthesis. 10/24/2020 Mrs Smith – S 3 BGE Biology 54
STARTER: KAHOOT – Mrs. Scientist. Smith
S 3 BGE L 3 -5 Biology Photosynthesis Word Equation Stored as starch We can prove each part of this word equation. We have proven that the raw materials carbon dioxide & water as well as the essential conditions light and chlorophyll must be present for photosynthesis to occur. In addition we have demonstrated that glucose is stored as starch. Today we are going perform a different experiment to show that oxygen is released as a by-product of photosynthesis. 10/24/2020 Mrs Smith – S 3 BGE Biology 56
Oxygen is a by-product of photosynthesis • When green plants photosynthesise they produce oxygen. • In aquatic plants like the Canadian pondweed Elodea, this oxygen is given off as bubbles which are easily seen. • The number of bubbles produced every minute, i. e. the rate, gives us an idea of how fast the plant is photosynthesising.
Elodea pond weed experiment to prove Oxygen is a by-product of photosynthesis AIM: To investigate that oxygen is produced as a by-product during photosynthesis • The following apparatus was set up (see opposite)…. • As the gas is released from the plant it floats up and displaces the water (shoves it aside) at the top of the tube
The test for oxygen – Relight a glowing splint AIM: To investigate that oxygen is produced as a by-product during photosynthesis When enough gas is collected the test tube is removed and a glowing splint is inserted into the tube to test for oxygen If the splint does not relight the gas is not oxygen. Because oxygen is very flammable it can easily relight a glowing splint
Testing a leaf for starch – Method Results and Conclusion AIM: To investigate that oxygen is produced as a by-product during photosynthesis Results: The pond weed could be observed releasing bubbles (gas). These collected at the top of the tube. When the gas was tested it relit a glowing splint. Conclusion: The results demonstrated that gas is given off as a by-product of photosynthesis. The gas relit a glowing splint this proves that the gas is oxygen. 10/24/2020 Mrs Smith – S 3 BGE Biology 60
PLENARY 1 : Card Sort activity 10/24/2020 Mrs Smith – S 3 BGE Biology Match the part of photosynthesis to be investigated with the correct method to do it. Make sure you understand this bit as you will need it for plenary 2 61
PLENARY 2: Complete the bringing it together worksheet (10 mins) 10/24/2020 Mrs Smith – S 3 BGE Biology 62
PLENARY 2: Complete the bringing it together worksheet HOW DID YOU DO? 10/24/2020 Place a potted plant in a bell jar plant in a dark cupboard with sodium deprive of light, hydroxide to leave for 48 hrs deprive of CO 2, leave for 48 hrs and test the leaf for starch. Treat Remember the control! the control plant as normal Do not water a potted plant to deprive of water, leave for 4872 hrs and test the leaf for starch. Treat the control plant as Mrs Smith – S 3 BGE Biology normal. Perform the elodea bubbler experiment, test the collected gas with a glowing splint Perform the basic testing the leaf for starch experiment using a VARIGATED LEAF (white and green) Test the leaf for starch: It will not prove glucose is present, but it does show it is stored as starch 63
National 5 Biology Have you achieved the Learning Intentions? CAN YOU…… o Describe the process of testing a leaf for starch. Specifically why each stage is performed! o Explain that water, carbon dioxide, light and chlorophyll are essential for photosynthesis to take place. (you should be able to describe what experiment will prove each of these!) o Describe an experiment to prove that oxygen is released as a byproduct of photosynthesis. 10/24/2020 Mrs Smith – S 3 BGE Biology 64
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