Products of photosynthesis - PowerPoint Presentation

1. Products of photosynthesisDo now activity:What are the limiting factors of photosynthesis?Explain the effect that an increase in temperature can have on the rate of photosynthesis.Describe a simple experiment that can be conducted to investigate the effect of light intensity on the rate of photosynthesis.

2. GOOD PROGRESS:State the products made by the plant using glucose from photosynthesisOUTSTANDING PROGRESS:Describe some of the important roles these products play within the plantProgress indicators

3. Products of PhotosynthesisJust like us a plant needs food for two reasons:For energyFor building it’s structure

4. Task: You’ve been sent a worksheet with some levelled questions. Make sure you write in full sentences and use as many key words as possible!Key Words:PhotosynthesisGlucoseOxygenCarbonNitrogenHydrogenStarchFatsRespirationSugarOilsEnergyStructure ProteinCelluloseExtension: Create an exam style question and mark scheme that you could give to a peer

5. Products of Photosynthesis1. When a plant cell needs energy it breaks down some of the glucose it makes during photosynthesis during which process? When does this process occur and how does this differ to photosynthesis?2. Plants convert some sugar into other substances such as starch, fats & oils, proteins and cellulose. Complete the table to show the roles they play in the plant: Energy StorageBuilding New Cells3. Which three elements are combined in a glucose molecule and which other element is needed in order to change the glucose into proteins?The energy for photosynthesis comes from _______. The energy is absorbed by the green pigment called _____________. This is found in structures in the cells called _____________. The main product of photosynthesis is a __________ called ___________. Some is used for _____________, to release energy. Some is converted into large molecules the plant needs, such as ______________, ___________ and ______________.34

6. 4. Explain why the plant that is short of nitrate ions has not been able to grow tall?Explain why plants store energy in the form of starch, rather than asglucose?6. Discuss the advantages and one disadvantages of storing energy as starch rather than as fats and oils.4. Sketch a diagram to show the difference between a healthy plant which has received nitrate ions and an unhealthy plant without nitrates: Healthy plantUnhealthy plant without nitrates+-?5/67+

7. The process which breaks down glucose is called respiration, this process happens throughout the day and the night. Whereas photosynthesis only occurs in the day.Fats & OilsStarchProteins – needed for making new cell membranes, cytoplasm and enzymesCellulose – needed for making cell wallsSelf-assessment:

8. Healthy potato plantUnhealthy potato plant

9. If a plant does not absorb sufficient amounts of nitrate ions it is unable to synthesis enough protein. If the plant does not have enough protein it will be unable to make new cell membranes, cytoplasm and enzymes which will slow down it’s growth. Plants store energy in the form of starch, instead of glucose, because starch is insoluble. This means that starch will not effect the water concentration inside cells and also it will not move away from the storage areas within the plant.

10. A positive commentA negative commentA question to further test their knowledge on the topicAn advantage of storing energy as starch, rather than fats and oils, is that it is easily stored by cells and is also easy to access. Starch is a quick molecule to break down to access the glucose needed for energy release.A disadvantage of using starch is that not as much energy can be stored per gram in comparison to fats & oils. For lightweight energy storage options, which plants often utilise in seeds, fats and oils are a good choice.

11. Carnivorous plantsCarnivorous plants such as Venus flytraps or pitcher plants live in nitrate-poor soils. How do they obtain the nutrients they need to survive?Plants will trap animals, release enzymes to digest the animals and then absorb the nitrates and other minerals they need from the animals body.

12. Iodine is a chemical that turns black when it detects starch. What would you expect to see if you tested different areas of these leaves for starch?

13. Investigate - Testing for starchIodine solution is used to test leaves for the presence of starch. You need to:Heat a plant leaf in boiling water for 30 seconds Heat it in boiling ethanol for a few minutes Wash with water and spread onto a white tileAdd iodine solution from a dropping pipetteAfter a few minutes observe the leaf, the parts of the leaf thatcontain starch turn blue-black.

14. Exam-style question:Green plants can make glucose, plants need energy to make this glucose. How do plants access this energy? (2 marks)Plants can use the glucose they have made to supply them with energy. Give four other ways in which plants use the glucose they have made.(4 marks)

15. Self-assessment:Light is trapped / absorbed / used By chlorophyll / chloroplasts (2)In order to make starch for storage to make fats/oils for storage to make amino acids / protein to make cellulose / cell walls (4)

16. Plenary – Silent 5What are the products of photosynthesis? (2 marks)Glucose can be stored as starch in plants. What are some of the other uses of glucose in the plant? (4 marks)Explain the effect temperature can have on the rate of photosynthesis within a plant (3 marks)

17. RespirationBoth animals and plants respire, plants carry out respiration as well. Plants respire all the time because their cells need energy to stay alive, but plants can only photosynthesise when they are in light and so only photosynthesise in the day.Making new substancesGlucose is a carbohydrate, plants can make different types of substances from the glucose they make during photosynthesis. This includes:Cellulose – another carbohydrate which is used to make cell wallsStarch – also a carbohydrate good for storing energyFats & oils – not a carbohydrate, also goo energy storesProteins – not a carbohydrate, needed to build new cell membranes, cytoplasm and enzymes.GlucoseProteinFats/oilsStarchCellulose

18. Mineral SaltsGlucose is made up from carbon, hydrogen and oxygen atoms. Plants make other substances from glucose. Fats & oils are also made up on carbon, hydrogen & oxygen. But proteins are made up of carbon, hydrogen, oxygen and nitrogen.Plants obtain nitrogen in the form of mineral ions, known as nitrates. Even though 80% of the air is made up of nitrogen it is very unreactive so is never incorporated into the plant via the air.The plants obtain nitrates from the soil, they absorb these mineral ions through their roots.Healthy potato plantUnhealthy potato plant

19. Starch polymer made up of glucose monomersChoosing the storage productPlants have choices when it comes to storing energy. Most plants store energy as starch. Starch is a polymer made up of many glucose monomers joined together in a chain. Starch is insoluble, it forms grains inside the cell to keep itself separate.Fats and oils are better molecules for storing energy in many ways. This is because they can store more energy per gram. The downside to fats & oils is that it is more difficult to break them down. Many seeds tend to have energy stored as oils, so it has a lighter weight to be carried away from the parent plant to grow.Using glucoseGlucose is made in photosynthesis and is transported around the plant as soluble sugar in the phloem. Much of the glucose is used in respiration and released as energy. However, glucose can also be converted into insoluble storage molecules – starch, fats & oils. The advantage of insoluble substances such as these are:They do not affect the water concentration inside cellsThey do not move away from the storage areas in the plantGlucose and starch can be converted into other substances in plants. For example:Cellulose for cell wallsProteins for growth and repair