Starter Activity: Divide the following into biotic and abiotic factors: Soil moisture, grazing, food availability, air temperature, light intensity, disease, predation, pH

Life on Earth Key Area 3 Photosynthesis

Photosynthesis Learning Intention: We are learning the overall process of photosynthesis. Success Criteria: Be able to state where photosynthesis occurs Be able to state the energy conversion during photosynthesis Be able to write the word equation for photosynthesis. Know what happens to the sugar made in photosynthesis

Skills for life, learning and work: Understanding new scientific terms Becoming confident in new biological terms Literacy, Numeracy, HWB: I can make notes and organise them to develop my thinking, help retain and recall information, explore issues and create new texts, using my own words as appropriate. LIT 3-15a / LIT 4-15a Using what I know about the features of different types of texts, I can find, select, sort, summarise, link and use information from different sources. LIT 3-14a / LIT 4-14a  

Watch and Listen Plants are Amazing!  Note key facts on a show me board

Energy All our energy comes from the sun. The sun gives the energy to plants. They make it into food in the form of sugars. Plants pass their energy on to animals which eat them. We eat the animals or plants (to get energy).

Plant Cell : what structures are the site of photosynthesis?

Chloroplasts Plant cells contain structures called chloroplasts which are located in the cytoplasm . These are green in colour as they contain a green chemical (pigment) called chlorophyll. Chlorophyll traps light energy from the sun. The plant uses this energy to make sugar in the process of photosynthesis.

Plants and Light PHOTO SYNTHESIS (Light) (To build) Plants manufacture their own food in a process called PHOTOSYNTHESIS. When a plant carries out photosynthesis it combines simple substances to make carbohydrates like glucose and starch. Photosynthesis is carried out in the leaves of a plant. PHOTO SYNTHESIS (Light) (To build)

Photosynthesis Sunlight is extremely important as it provides the energy for plants to make their own food. Cells in green plants make their own food in a process known as photosynthesis. Photosynthesis is an enzyme-controlled process where light energy from the sun is trapped by chlorophyll and converted into chemical energy. (light energy chemical energy) Chlorophyll is a green pigment (colour) found in disc-shaped structures called chloroplasts in green leaves.

Watch and Listen Photosynthesis Video Clip While watching this clip, think about how green plants affect the composition of gases in the atmosphere.

Photosynthesis Equation Light energy Carbon Dioxide + Water Glucose Oxygen trapped by chlorophyll Raw Materials Products

released from air traps light energy in leaves (glucose) from soil

Photosynthesis Photosynthesis

Photosynthesis Photosynthesis

Uses of sugars in plants

The 3 fates of glucose Glucose So what happens to the sugar made in the leaves? It can be used in a number of ways: Used to make starch (storage) and converted back when sugar is needed by plant Used to make cellulose (structural) in cell walls Glucose Used immediately for respiration

Starch A single starch molecule can be made up from around 200-800 glucose molecules. The picture shows starch grains inside plant cells, stained with iodine.

Cellulose A single cellulose molecule is likely to be made up from around 1000 – 1500 glucose molecules. Cellulose is made up of chains of glucose molecules which form fibres. View of the cell wall of a plant cell under the electron microscope showing a mesh of cellulose fibres.

Have we succeeded? Learning Intention: We are learning the overall process of photosynthesis. Success Criteria: Be able to state where photosynthesis occurs Be able to state the energy conversion during photosynthesis Be able to write the word equation for photosynthesis. Know what happens to the sugar made in photosynthesis

Photosynthesis Learning Intention: We are learning about the conditions needed for photosynthesis Success Criteria: Be able to take part in investigations to prove that a leaf is photosynthesising Be able to describe the experiment carried out Be able to name the solution used to test for starch Know the conditions needed for photosynthesis

Skills for life, learning and work: Literacy, Numeracy, HWB: When I engage with others I can make a relevant contribution, ensure that everyone has an opportunity to contribute and encourage them to take account of others’ points of view or alternative solutions. I can respond in ways appropriate to my role, exploring and expanding on contributions to reflect on, clarify or adapt thinking. LIT 4-02a I make full use of and value the opportunities I am given to improve and manage my learning and, in turn, I can help to encourage learning and confidence in others. HWB 3-11a / HWB 4-11a Skills for life, learning and work: Confidence in yourself and your abilities Communication Independent learning Understanding of new scientific terms Enquiry and practical

Right’s Respecting School: UN Convention of the Right’s of a Child Article 15: Every child has the right to meet with other children and to join groups and organisations, as long as this doesn’t stop other people from enjoying their rights. Research hwk- causes and types of diabetes, what it is etc.

Starter Activity: On a show me board, using no notes, write out the photosynthesis word equation. Make sure you label the raw materials and products. Question - How do green plants affect the composition of gases in the atmosphere?

Investigating Conditions Needed for Photosynthesis Before we can carry out investigations to find out the conditions required for photosynthesis, we need to know the process for proving that a leaf has photosynthesised. What do you think we will test a leaf for? (Clue : how do plants store the sugar they make in photosynthesis?)

Testing a leaf for starch Before we can add iodine to a leaf, we need to prepare the leaf as follows: Boil the leaf in water to remove the waxy coating so our stain can get inside the leaf. Place the leaf in hot ethanol to remove the green colour so we can see the colour change. What colour change indicates a positive test with iodine?

Testing a leaf for starch

Equipment you will need 200 ml of water in 250 ml beaker White tile

Method Place the leaf or leaf discs in a beaker of water. Sit the beaker on a tripod stand and use a bunsen burner to heat the water. Once it is fully boiling, allow to boil for 2 minutes. TURN OFF THE BUNSEN BURNER. Using tweezers, remove the leaf or discs. Place the leaf in a boiling tube and cover with ethanol. Place the boiling tube into the beaker of water. Once the ethanol has turned green, tip the contents of the boiling tube into the hot water to rinse the leaf. Place the leaf or discs on a white tile and add iodine solution.

Proving that light is required Discuss with your partner how you think you could prove that light is required for photosynthesis to take place. Your teacher will listen to all of your ideas. You will then carry out an experiment to prove your hypothesis.

Starter Activity: What leaf (Q or R) would test positive for starch? Why?

Photosynthesis Learning Intention: We are using skills we have already learned to carry out another photosynthesis investigation. Success Criteria: Be able to carry out an investigation to prove that chlorophyll is required for photosynthesis.

Skills for life, learning and work: Literacy, Numeracy, HWB: When I engage with others I can make a relevant contribution, ensure that everyone has an opportunity to contribute and encourage them to take account of others’ points of view or alternative solutions. I can respond in ways appropriate to my role, exploring and expanding on contributions to reflect on, clarify or adapt thinking. LIT 4-02a I make full use of and value the opportunities I am given to improve and manage my learning and, in turn, I can help to encourage learning and confidence in others. HWB 3-11a / HWB 4-11a Skills for life, learning and work: Confidence in yourself and your abilities Communication Independent learning Understanding of new scientific terms Enquiry and practical

Proving that chlorophyll is required Discuss with your partner how you think you could prove that chlorophyll is required for photosynthesis to take place. Your teacher will listen to all of your ideas. You will then carry out an experiment to prove your hypothesis.

Conditions required for photosynthesis You will now carry out the test for starch on a variegated leaf. This is a leaf which has some white areas, which do not contain chlorophyll. What is your hypothesis? (What do you think will happen)

Method Place the leaf in a beaker of water. Sit the beaker on a tripod stand and use a bunsen burner to heat the water. Once it is fully boiling, allow to boil for 2 minutes. TURN OFF THE BUNSEN BURNER. Using tweezers, remove the leaf. Place the leaf in a boiling tube and cover with ethanol. Place the boiling tube into the beaker of water. Once the ethanol has turned green, tip the contents of the boiling tube into the hot water to rinse the leaf. Place the leaf on a white tile and add iodine solution.

Write up Write up your experiment including your aim, variables, method and results. You must include a labelled diagram. You must include the reasons for boiling the leaf and for heating it in ethanol.

Have we succeeded? Learning Intention: We are using skills we have already learned to carry out another photosynthesis investigation. Success Criteria: Be able to carry out an investigation to prove that chlorophyll is required for photosynthesis.

Starter Activity: Describe an experiment which shows that light is required for photosynthesis.

Photosynthesis Learning Intention: We are learning the two stages of photosynthesis Success Criteria: Be able to name, describe and explain stage 1 and stage 2 of photosynthesis Be able to state the conditions required for stage 1 and stage 2

Skills for life, learning and work: Understanding new scientific terms Becoming confident in new biological terms Literacy, Numeracy, HWB: I can make notes and organise them to develop my thinking, help retain and recall information, explore issues and create new texts, using my own words as appropriate. LIT 3-15a / LIT 4-15a Using what I know about the features of different types of texts, I can find, select, sort, summarise, link and use information from different sources. LIT 3-14a / LIT 4-14a  

Right’s Respecting School: UN Convention of the Right’s of a Child Article 17: Every child has the right to reliable information from the media. This should be information that children can understand. Governments must help protect children from materials that could harm them. Research hwk- causes and types of diabetes, what it is etc.

Photosynthesis Song

Photosynthesis Light energy Carbon Dioxide + Water Glucose Oxygen CO2 C6H12O6 O2 Raw Materials Products

Photosynthesis - Stage 1 Photosynthesis happens in 2 stages. Stage 1 is called the Light Reactions.

Light energy trapped by chlorophyll used to split water Water is split into oxygen and hydrogen Oxygen diffuses from the cell Hydrogen is used in stage 2

Light energy Light energy trapped by chlorophyll in chloroplasts and converted to chemical energy Chemical energy used to generate ATP (an energy transfer molecule) ATP is used in stage 2

Light Reactions Occur in the chloroplasts. Splitting of water into oxygen and hydrogen. Oxygen is produced and excess oxygen diffuses into the air. Light energy is converted to chemical energy in the form of ATP. ATP and hydrogen are transferred to stage 2.

Starter Activity: Answer the following questions in your class work jotter: Name the two raw materials of photosynthesis. Name stage 1. What is the energy change that takes place? Name two products made in stage 1 that are required for stage 2.

Photosynthesis - Stage 2 Stage 2 is called Carbon Fixation. It is a series of enzyme controlled reactions that form a cycle. ATP from stage 1 provides energy for this process. Hydrogen from stage 1 combines with CO2 from the air to form glucose.

ATP from stage 1 provides energy for reaction Hydrogen from stage 1 combines with carbon dioxide Glucose formed Carbon dioxide from air enters reaction Used in respiration, or converted to starch or cellulose

Photosynthesis summary diagram oxygen released hydrogen Series of enzyme controlled reactions Energy from ATP

Task In groups, pupils should play a part in a short production to show their class what happens during the whole process of photosynthesis. Each person in the group must take part. You may use Show Me Boards or paper to help demonstrate the process.

Consolidation Task Collect a National 5 text book and read pages 76 to 83. You must complete: Activity 7.1 working individually in your notebook, answering in FULL sentences. You should complete: Activity 7.2 working individually in your notebook, You could complete: Activity 7.3 working in pairs on A3 paper.

Have we succeeded? Learning Intention: We are learning the two stages of photosynthesis Success Criteria: Be able to name, describe and explain stage 1 and stage 2 of photosynthesis Be able to state the conditions required for stage 1 and stage 2

Starter Activity: Answer on a show me board: What two substances is the glucose made in photosynthesis converted to?

Photosynthesis Learning Intention: We are learning about the limiting factors of photosynthesis. Success Criteria: Be able to name the three limiting factors of photosynthesis. Be able to carry out an investigation to measure the rate of photosynthesis.

Skills for life, learning and work: Understanding new scientific terms Becoming confident in new biological terms Literacy, Numeracy, HWB: I can make notes and organise them to develop my thinking, help retain and recall information, explore issues and create new texts, using my own words as appropriate. LIT 3-15a / LIT 4-15a Using what I know about the features of different types of texts, I can find, select, sort, summarise, link and use information from different sources. LIT 3-14a / LIT 4-14a  

Photosynthesis Photosynthesis CANNOT work without: Carbon dioxide The correct temperature Light If any of the above are in short supply they are said to be limiting factors.

Limiting Factors The three limiting factors of photosynthesis are: temperature, carbon dioxide concentration and light intensity. By increasing these factors, you can increase the rate of photosynthesis and therefore, increase the rate of plant growth.

Measuring the rate of photosynthesis This can be measured by: -rate of CO2 uptake -rate of O2 production -rate of build up of starch/carbohydrate The easiest of these to measure is O2 production in plants which live in water.

Pondweed Cabomba Elodea These plants produce tiny oxygen bubbles which are released into the water. This is good for the fish in a fish tank! What do the plants get from the fish in return?

Cabomba / Elodea bubbler By counting the bubbles of oxygen released per unit of time, we can measure the rate of photosynthesis

Elodea Bubbler What could be limiting the rate of photosynthesis at point X? What could be limiting the rate of photosynthesis at point Y? What could be limiting the rate of photosynthesis at point Z? 0.5 conc of CO2 250C Y 0.5 conc of CO2 150C Z X

Elodea Bubbler What happens as light intensity increases? The rate of photosynthesis increases then levels off. Why does it level off? Something else must be in short supply.

Elodea This animation helps demonstrate how limiting factors affect the rate of photosynthesis. http://www.kscience.co.uk/animations/photolab.htm

Measuring rate of photosynthesis with Elodea (pondweed) Upside down test tube (to collect oxygen gas) Thermometer Solution of sodium carbonate (a source of CO2) funnel elodea lamp How could the light intensity be altered? How could the temperature be altered (and kept constant)? How could the CO2 concentration be altered? How can the rate of photosynthesis be measured?

Rate of photosynthesis

Rate of photosynthesis http://www.kscience.co.uk/animations/photolab.swf http://www.kscience.co.uk/animations/photolab.swf Rate of photosynthesis

Light intensity as a limiting factor At A, low light intensity is limiting the rate of photosynthesis. At B, light intensity is high, so another factor must be in short supply (carbon dioxide concentration or temperature). B A Light intensity

Carbon dioxide concentration as a limiting factor At A, low carbon dioxide concentration is limiting the rate of photosynthesis. At B, carbon dioxide concentration is high, so another factor must be in short supply (light intensity or temperature). B A Carbon dioxide concentration

Temperature as a limiting factor At A, low temperature is limiting the rate of photosynthesis. At B, temperature is high, so another factor must be in short supply (carbon dioxide concentration or light intensity). But what happens after 40°C? B A 20 40 Temperature (°C)

Temperature as a limiting factor At very high temperatures, the rate of photosynthesis drops down to zero. Why do you think this happens?

Limiting factor graphs The temperature graph is different due to the enzymes that control photosynthesis being denatured at high temperatures.

Limiting Factors Light Intensity At this point, something other than light intensity is the limiting factor. It must be either CO2 concentration or temperature. As a general rule, whatever is on the x-axis is the limiting factor on the slope of the graph. At this point, light intensity is the limiting factor Light Intensity

What’s the limiting factor? Your teacher will add a label to the x axis. You can then try to complete the sentences. At A, low ________________ is the limiting factor. At B, ___________ or ______________ is the limiting factor. B A

Have we succeeded? Learning Intention: We are learning to investigate the limiting factors of photosynthesis Success Criteria: Be able to name the three limiting factors of photosynthesis Be able to carry out an investigation to measure the rate of photosynthesis

N5 Life on Earth Key Area 3 Photosynthesis Past Paper Practice National 5 N5 Life on Earth Key Area 3 Photosynthesis

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N5 Life on Earth Key Area 3 ANSWERS Past Paper Practice National 5 N5 Life on Earth Key Area 3 ANSWERS

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2 Photosynthesis is controlled by enzymes / enzymes are needed 1 (At high temperatures) enzymes are denatured/do not work. 1

3 Light Intensity Temperature (either order) Both required Not Acceptable – Heat or light

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9 Light energy is trapped by chlorophyll Light energy/it is converted into ATP ATP goes from stage 1 to stage 2 Any two points from three — 1 mark each Chemical energy is converted into sugar 1 mark

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