Downloaded 25 times
More Related Content
Similar to B2.3 photosynthesis
B2.3 photosynthesis
- 1.
- 2. B2.3 Photosynthesis Green plantsand algae use light energy to make their own food. They obtain the raw materials they need to make this food from the air and the soil. The conditions plants are grown in can be changed to promote growth.
- 3. You need tobe able to: ■ interpret data showing how factors affect the rate of photosynthesis ■ evaluate the benefits of artificially manipulating the environment in which plants are grown.
- 4.
- 5.
- 6. Function of leaves •Trap light energy for photosynthesis Producing sugar from photosynthesis • Exchange of gases – oxygen and carbon dioxide
- 8. Structure Wide Helps to catchmore light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis
- 9. Leaf structure Greener ontop CO2 gets in here
- 10. Leaf diagram –palisade layer CO2 Most chlorophyll
- 11. Leaf cell -palisade Position? Upper surface of leaf Features? Box shape Chloroplasts Function? Photosynthesis
- 12. Gas exchange • Leavesare designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf • They have small holes called stomata on the under surface • Each hole is open & closed by 2 guard cells
- 13. Leaf diagram – stomaand guard cells
- 14.
- 15. Stoma is asmall hole Its size is controlled by 2 guard cells closed open
- 16. Stoma function isfor gas exchange in the leaf Carbon dioxide oxygenGuard cell Provided plant is photosynthesising
- 17. Stomata open and closeat different times of the day When it is light the plant needs CO2 for photosynthesis so the stoma open At night (darkness) they close
- 18.
- 19. Cross section ofa leaf Add the labels to your diagram
- 20. The top surfacehas a thick waxy cuticle to stop water evaporating from the cells The top layer of cells is closely packed and contain lots of chloroplasts because these carry out most of the photosynthesis (Palisade layer) Cross section of a leaf Veins contain xylem tubes to carry water to the leaf cells from the roots and via the stem Pores called stoma let gases in/out the leaf. They are on the bottom so they are not blocked and are shaded to prevent evaporation. Guard cells can shut them to control water loss The lower layer of cells has air spaces between to let carbon dioxide move towards the top surface and a big surface area for gas exchange Add the labels to your diagram
- 21. Roots – functionand structure • Hold plant in position • Absorb water and minerals from the soil • Specialised cells to increase surface area for water intake
- 22. Wheat seed Root hairs Fragileparts of cells that grow from the main root They massively increase the surface area for absorption
- 23. Root hair cells(x150)
- 24. Root ‘B’ hashad the hairs damaged - Toughened root cap
- 30. e) The glucoseproduced in photosynthesis may be converted into insoluble starch for storage. Plant cells use some of the glucose produced during photosynthesis for respiration.
- 31. f) Some glucosein plants and algae is used: ■ to produce fat or oil for storage ■ to produce cellulose, which strengthens the cell wall ■ to produce proteins.
- 32. g) To produceproteins, plants also use nitrate ions that are absorbed from the soil.
- 33. In a sciencefiction book, a villain threatens to spray the countryside with a chemical that destroys chlorophyll (the green substance in plants). What effect will this have on plant life? Explain your answer as fully as you can.
- 34. A farmer cutshis meadow for hay. He noticed that the grass he cut was green, but the stalks were yellow. How do you explain this?
- 35. A small treeis planted in a meadow. After 20 years it has grown into a big tree, weighing 250 kg more than when it was planted. Where do you think the extra 250 kg come from? Explain your answer as fully as you can.
- 36. Plants and minerals Anumber of plants seedlings are placed into a water culture and fed with various nutrients. One is fed with only distilled water, the others are fed with nutrients but one without Nitrogen, another without Iron, another without Magnesium and another without Phosphorous. The final one is fed with all the nutrients.
- 37. Describe the appearanceof the plants in each tray Which plant looks healthiest? What can you conclude?
- 39. Very little growth Poor growth Yellowish leaves ■ to producefat or oil for storage ■ to produce cellulose, which strengthens the cell wall ■ to produce proteins. Carbon dioxide + water -> Glucose + Oxygen 6CO2 + 6H2O -> C6H12O6 + 6O2
- 40.