1. Photosynthesis 1 ! Exam booklet 2 3 4567 8 9 10 11 12 13 14 !

2. Water is split into oxygen And hydrogen/ hydrogen ions Light energy raises electrons to higher energy level Electrons received by photosystem II

3. ATP Provides energy Reduced N ADP/ N ADPH Reduces GP/ passes H to GP

4. Electrons in chlorophyll/ photosystems are raised to higher energy level by light Electrons pass along transfer chain The energy is used to make ATP from ADP and Pi Electrons (and H + ) reduce N ADP H + come from photolysis

5. They are used in the light independent stage/ Calvin cycle To convert GP to TP The reduced N ADP supplies hydrogen atoms The ATP supplies energy

6. Reduced by electrons From photolysis / chlorophyll

8. RuBP reacts with carbon dioxide to form 2 molecules of GP

9. Less is used to combine with carbon dioxide / Less used to form GP

10. Carbon dioxide is used in photosynthesis / Will allow detection of products

11. ATP and reduced N ADP are not produced GP is not being used to form RuBP

12. Used in respiration/ formation of starch/ cellulose

14. Original / 100% reading – light meter reading

15. Oxygen produced / change in oxygen concentration in unit time

16. Oxygen is produced in light dependent reaction Light energy absorbed by chlorophyll/ excites electrons Electrons leave the chlorophyll Photolysis of water occurs Electrons replaced in chlorophyll

18. Red light leads to more photosynthesis / more oxygen produced with red light (compared to green light) More red light absorbed (by chlorophyll) (Most) green light reflected Bacteria need oxygen to respire

19. Water is split using light energy It provides electrons/ hydrogen ions Replaces the electrons lost by chlorophyll Provides hydrogen ions for ATP production

21. It binds to chlorophyll molecules Prevents the release/ absorption of electrons Stops the movement of electrons down the first transport chain So the breakdown of water reduces

22. Less ATP produced For the Calvin cycle/ light independent reaction So less sugar produced for respiration Rate of reaction becomes greater than the rate of photosynthesis

23. Reduced N ADP/ N ADPH

24. 2

25. Less GP formed So less TP Less RuBP regenerated/ made Less CO 2 taken up

27. High levels of oxygen reduce the rate of photosynthesis, effect greater at higher temperatures Higher concentration means more effective competitor/ more RuBP reacts with oxygen

28. ATP Reduced N ADP / N ADPH O 2 produced / CO 2 taken up To ensure a high rate of photosynthesis/ so that neither factor is limiting

29. More photosynthesis when the dark period increased from 3 to 17ms Even though amount of light is the same

30. Products made in the light dependent system have been used up (in 17ms)

32. Few/no trees already present Species X has high rate of photosynthesis at high light intensities Species X trees grow fastest at high light intensities X will outcompete Y/Z

33. Species X trees will provide shade / reduce light intensity Species Z grows best/ more photosynthesis in low light intensity

34. High concentration of CO 2 at night/ darkness N o photosynthesis in dark/ light required for light dependent stage Plants respire [all the time] In the light there is a net uptake of CO 2 by plants/ rate of photosynthesis is higher than rate of respiration Decrease in CO 2 concentration with height At ground level less light/ less photosynthesis

35. Carbon dioxide combines with ribulose bisphosphate/ RuBP To produce two molecules of glycerate 3-phosphate/ GP GP is reduced to TP Which requires reduced N ADP/ N ADPH And energy from ATP

38. 24 2 = 576 1  576 = 0.0017 0.0017

39. Radius/ diameter of the capillary tube Bubble in CO 2 Add(dissolved) hydrogen carbonate

40. Oxygen used in respiration Oxygen would dissolve in the water Oxygen may leak from the apparatus May remain as bubble in leaf air spaces

41. N itrogen present in the air in the leaf/ Will leave leaf with the oxygen/ May come out of solution Level higher than expected/ normal/ in atmosphere Plant is respiring/ produces CO 2 CO 2 has been added to the water/ present in excess Comes out of solution

42. Intensity: less/lower light intensity in deep water pigments can absorb what light there is Wavelength: not all wavelengths of light can penetrate/ mainly short wavelengths/ mostly blue light penetrates pigments can absorb these wavelengths

43. Light intensity

44. Some other factor is now limiting the rate e.g. carbon dioxide concentration or temperature

45. 1

46. Rate increases when temperature increases from 15 O C to 25 O C Rate increases when carbon dioxide concentration increases from 0.04% to 0.4%

47. Enzymes will (start to) denature E.g. rubisco Active site will change shape Less photolysis Less ATP produced Named step in Calvin cycle affected Increased rate of transpiration Stomata will close Less carbon dioxide taken in

48. Less reflection of light More light absorbed More wavelengths of light absorbed More ATP / reduced NADP produced Temperature of leaf will increase Enzymes work more effectively Reduces limiting effect of light intensity / temperature

51. As a control To show that light is producing the effect

53. Cut discs the same size To give same surface area Cut discs from same/similar part of leaf To give same amount of chloroplasts

54. Carry out at same temperature Temperature affects enzyme action/structure Carry out repeats To calculate means/identify anomalous results

55. Place lamp same distance from tubes To give same light intensity Use filters of same thickness To give same light intensity

56. Carry out in darkened room To ensure only one wavelength of light Give CO 2 in excess So that CO 2 is not a limiting factor

57. Use same volume/concentration of indicator So that colour changes can be compared Put heat sink between lamp and tubes To minimise temperature changes

58. Chlorophyll a Chlorophyll reflects/does not absorb green light Little/no photosynthesis/light dependent reaction Little/no photolysis/ splitting of water Little/no CO 2 taken up Some CO 2 produced in respiration CO 2 increases acidity/ lowers pH

59. Photosynthesis is controlled by enzymes Optimum temperature can be controlled with heaters/ ventilation/air conditioning CO 2 can be increased by burning gas/paraffin CO 2 will not be a limiting factor/ Calvin cycle will increase

60. Obtaining individual organelles Chlorophyll a Chlorophyll b Carotene Xanthophyll Fucoxanthin

61. From water Water is split in photolysis Linked to photosystem 2 Reduced N ADP/ N ADPH

62. Chloroplasts retain biochemical activity Prevent activity of (lysosome) enzymes Prevent membrane/protein damage Buffer keeps pH constant No (net) water movement/ osmosis So no change in volume/ turgidity of chloroplasts

64. blue gree n

65. Boiled suspension: enzymes denatured change in tertiary structure/ active site no photolysis no hydrogen released DCPIP remains blue/ oxidised photosystems damaged by heat

66. The End !