TRB PG Assistant - Photosynthesis: photosystem I and photosystem II and their bioinorganic aspects Online Test (MCQ Quiz)

1. Which metal ion is the central atom in the reaction center of Photosystem I (PSI)?

A) Magnesium (Mg^2+) B) Iron (Fe^2+/Fe^3+) C) Manganese (Mn^2+) D) Copper (Cu^+/Cu^2+)

2. What is the primary role of Photosystem II (PSII) in photosynthesis?

A) To generate ATP through chemiosmosis B) To oxidize water and release oxygen C) To reduce NADP+ to NADPH D) To capture light energy for carbon fixation

3. The oxygen-evolving complex (OEC) in Photosystem II is primarily associated with which metal ion?

A) Iron B) Manganese C) Calcium D) Magnesium

4. In Photosystem I, the primary electron acceptor is a molecule called:

A) Pheophytin B) Plastoquinone C) A 4Fe-4S cluster (ferredoxin) D) Chlorophyll a_0

5. Which pigment molecule is considered the reaction center chlorophyll in Photosystem II?

A) Chlorophyll b B) Carotenoid C) P680 D) P700

6. The electron transport chain between Photosystem II and Photosystem I involves which of the following carriers?

A) Cytochrome b6f complex B) Plastocyanin C) Plastoquinone D) All of the above

7. What is the typical absorption maximum wavelength for the reaction center chlorophyll of Photosystem I (P700)?

A) 680 nm B) 700 nm C) 650 nm D) 430 nm

8. The splitting of water (photolysis) in Photosystem II requires the presence of:

A) ATP and NADPH B) Light energy and a manganese cluster C) Carbon dioxide and RuBisCO D) Cytochrome c and plastocyanin

9. Which of the following is a key bioinorganic component of the electron transfer pathway in Photosystem I?

A) Manganese cluster B) Cytochrome b6f complex C) 4Fe-4S clusters D) Copper ions

10. The role of plastocyanin in the photosynthetic electron transport chain is to:

A) Carry electrons from PSII to the cytochrome b6f complex B) Carry electrons from the cytochrome b6f complex to PSI C) Carry electrons from PSI to NADP+ reductase D) Carry protons across the thylakoid membrane

11. The P680 reaction center chlorophyll in Photosystem II is oxidized by:

A) Water B) A tyrosine residue (Z) C) Light energy D) Plastoquinone

12. Which complex contains the primary electron donor P700 in Photosystem I?

A) Light-harvesting complex I (LHCI) B) Reaction center of PSI C) Cytochrome b6f complex D) Photosystem II

13. The bioinorganic center responsible for the oxidation of water in PSII is a tetrameric cluster of:

A) Fe-S B) Cu-Zn C) Mn-Ca D) Mg-Cl

14. Which molecule directly receives electrons from Photosystem I to reduce NADP+?

A) Plastquinone B) Ferredoxin C) Plastocyanin D) Cytochrome f

15. The primary function of the light-harvesting complexes (LHCs) associated with PSI and PSII is to:

A) Catalyze water splitting B) Transfer absorbed light energy to the reaction centers C) Reduce NADP+ D) Generate ATP

16. The 'Z-scheme' of photosynthesis refers to the energy levels of electrons as they move through:

A) The Calvin cycle B) The electron transport chain involving PSI and PSII C) ATP synthase D) The light-independent reactions

17. The bioinorganic component that acts as a mobile electron carrier between PSII and the cytochrome b6f complex is:

A) Plastocyanin B) Plastoquinone C) Ferredoxin D) Cytochrome f

18. In Photosystem II, the electron lost by P680 is ultimately replaced by an electron from:

A) Water B) Plastoquinone C) ATP D) NADPH

19. Which of the following is NOT a component of the electron transport chain linking PSII and PSI?

A) Plastoquinone B) Cytochrome b6f complex C) Ferredoxin D) Plastocyanin

20. The reaction center chlorophyll of Photosystem I is designated as:

A) P680 B) P700 C) P870 D) P580

21. Which metal ion is essential for the catalytic activity of the NADP+ reductase enzyme, which receives electrons from PSI?

A) Magnesium B) Manganese C) Iron D) Copper

22. The primary role of the oxygen-evolving complex (OEC) is to:

A) Reduce NADP+ B) Generate ATP C) Catalyze the oxidation of water to O2 D) Transfer electrons to P680

23. Which of the following is a primary electron acceptor in Photosystem II?

A) A 4Fe-4S cluster B) Plastoquinone C) Chlorophyll a_0 D) P700

24. The bioinorganic cofactor in the reaction center of Photosystem I that is responsible for the initial electron transfer is:

A) Chlorophyll a B) Pheophytin C) A special pair of chlorophyll a molecules (P700) D) Beta-carotene

25. The 'plastoquinone pool' in the thylakoid membrane functions to:

A) Transfer electrons from PSI to NADP+ B) Transfer electrons from PSII to the cytochrome b6f complex C) Transfer electrons from the cytochrome b6f complex to PSI D) Transfer protons from the stroma to the lumen

26. Which element is crucial for the stability and function of the chlorophyll molecules within the photosystems?

A) Iron B) Magnesium C) Manganese D) Copper

27. The electron flow from Photosystem I directly leads to the reduction of:

A) Water B) Oxygen C) NADP+ D) ATP

28. The cytochromes in the cytochrome b6f complex contain heme groups, which are iron-containing porphyrin structures, essential for:

A) Light absorption B) Electron transfer C) Water oxidation D) NADPH production

29. In Photosystem II, the electron lost by P680 is transferred to pheophytin, and then to:

A) Plastocyanin B) Plastoquinone C) Ferredoxin D) Cytochrome f

30. The bioinorganic component that bridges the electron transport between the cytochrome b6f complex and Photosystem I is:

A) Plastoquinone B) Ferredoxin C) Plastocyanin D) Cytochrome b559

31. What is the role of accessory pigments (like chlorophyll b and carotenoids) in the photosystems?

A) Directly oxidize water B) Transfer energy to the reaction center chlorophyll C) Reduce NADP+ D) Generate ATP

32. The 'water splitting' reaction in PSII produces electrons, protons, and:

A) Hydrogen peroxide B) Oxygen C) Ozone D) Water vapor

33. Which metal ion is part of the reaction center chlorophyll (P700) in Photosystem I?

A) Manganese B) Copper C) Iron D) Magnesium

34. The high redox potential of P680+ in Photosystem II is crucial for:

A) Reducing NADP+ B) Oxidizing water C) Generating ATP D) Transferring electrons to P700

35. The bioinorganic components of the Fe-S centers in Photosystem I are responsible for:

A) Light absorption B) Proton pumping C) Electron transfer D) Water oxidation

36. Which of the following is the terminal electron acceptor in the linear electron flow of photosynthesis?

A) Water B) Plastocyanin C) NADP+ D) Oxygen

37. The 'dark reactions' (Calvin cycle) are directly dependent on the products of the light-dependent reactions, which are:

A) Oxygen and water B) ATP and NADPH C) Light energy and CO2 D) Chlorophyll and carotenoids

38. The proton gradient generated across the thylakoid membrane by the electron transport chain is used by:

A) Photosystem I B) Photosystem II C) ATP synthase D) NADP+ reductase

39. Cytochrome f, a component of the cytochrome b6f complex, contains a heme group with which metal ion?

A) Manganese B) Copper C) Iron D) Magnesium

40. The bioinorganic cluster in PSII that directly receives electrons from P680 is:

A) A 4Fe-4S cluster B) Plastoquinone C) Pheophytin D) A Mn4CaO5 cluster

41. Which of the following is a key role of copper ions in photosynthetic electron transport?

A) Catalyzing water splitting B) Part of the P700 reaction center C) Involved in electron transfer in plastocyanin D) Primary electron acceptor in PSII

42. The reduction of P700+ in Photosystem I by plastocyanin occurs in the:

A) Stroma B) Thylakoid lumen C) Thylakoid membrane D) Outer chloroplast membrane

43. The overall function of the photosystems and associated electron transport chain is to convert light energy into chemical energy in the form of:

A) Glucose and oxygen B) ATP and NADPH C) Carbon dioxide and water D) Heat and light

44. Which of the following is a characteristic of the bioinorganic center of Photosystem I's reaction center?

A) Contains a manganese cluster for water oxidation B) Has P680 as its primary electron donor C) Involves 4Fe-4S clusters for electron transfer D) Its primary electron acceptor is plastoquinone

45. The bioinorganic aspect of Photosystem II's function involves the manganese cluster's ability to:

A) Absorb light energy B) Transfer electrons to P680 C) Facilitate the oxidation of water D) Reduce NADP+

46. The 'cyclic electron flow' in photosynthesis primarily involves:

A) Only Photosystem I B) Only Photosystem II C) Both Photosystem I and II D) The Calvin cycle

47. In cyclic electron flow, electrons from ferredoxin are returned to:

A) Photosystem II B) Plastoquinone C) The cytochrome b6f complex D) NADP+

48. The primary bioinorganic component that acts as the electron donor to P700 in Photosystem I during cyclic electron flow is:

A) Water B) Plastocyanin C) Plastoquinone D) Cytochrome f

49. The function of cyclic electron flow is primarily to generate:

A) NADPH B) ATP C) Oxygen D) Glucose

50. Which metal ion is proposed to play a role in stabilizing the structure of chlorophyll antennae complexes?

A) Iron B) Manganese C) Magnesium D) Calcium

Photosynthesis: photosystem I and photosystem II and their bioinorganic aspects - Online Test

Test Results