General
✓✗Which of the following was NOT known by the middle of the nineteenth century?
- The O2 released comes from water.
- Plants use CO2 and water.
- Plants release O2.
- Plants use light energy.
General
✓✗Electrons from the PS I acceptor reduce NADP+ to NADPH + H+. The protons needed for this come from
- the Calvin cycle
- the outer membrane
- the lumen
- the stroma
General
✓✗Assertion (A): The thylakoid lumen becomes acidic during the light reaction.
Reason (R): Protons from water splitting and from the hydrogen carrier accumulate in the lumen.
Reason (R): Protons from water splitting and from the hydrogen carrier accumulate in the lumen.
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, but R is not the correct explanation of A.
- A is true but R is false.
- Both A and R are false.
General
✓✗The Calvin cycle occurs in the
- mitochondria
- glyoxysomes
- cytoplasm
- chloroplasts
General
✓✗How many molecules of 3-PGA are formed when six molecules of CO2 are fixed?
- 6
- 12
- 18
- 3
General
✓✗Within a photosystem, the reaction centre is formed by
- a carotenoid molecule
- a chlorophyll b molecule
- a single chlorophyll a molecule
- a molecule of ferredoxin
General
✓✗Plants in which the first product of CO2 fixation is a 3-carbon acid are called
- C2 plants
- C3 plants
- C4 plants
- CAM plants
General
✓✗If the light reactions of a chloroplast are stopped (for example, by darkness), the Calvin cycle
- soon stops, because ATP and NADPH run out
- speeds up, because more CO2 becomes available
- continues indefinitely
- reverses and releases O2
General
✓✗The first stable product of CO2 fixation in sorghum is
- oxaloacetic acid
- phosphoglyceric acid
- succinic acid
- pyruvic acid
General
✓✗Which of the following is NOT a product of the light reaction of photosynthesis?
- ATP
- NADPH
- NADH
- oxygen
General
✓✗In Engelmann's experiment, aerobic bacteria were used to
- fix nitrogen for the alga
- absorb light of particular wavelengths
- supply CO2 to the alga
- detect the sites of O2 release
General
✓✗Match List I with List II.
| List I | List II |
| P. Absorption spectrum | 1. Single chlorophyll a molecule that loses an excited electron |
| Q. Action spectrum | 2. Light absorbed by a pigment at different wavelengths |
| R. Reaction centre | 3. Pigments that pass energy to the reaction centre |
| S. Antenna | 4. Rate of photosynthesis at different wavelengths |
- P-1, Q-3, R-2, S-4
- P-2, Q-4, R-1, S-3
- P-2, Q-4, R-3, S-1
- P-4, Q-2, R-1, S-3
General
✓✗Absorption of light by the reaction-centre chlorophyll of a photosystem results in
- direct evolution of O2 from the chlorophyll
- reduction of the chlorophyll
- absorption of CO2 by the chlorophyll
- oxidation of the chlorophyll
General
✓✗Match List I with List II.
| List I | List II |
| P. RuBP | 1. First stable product in C3 plants |
| Q. 3-PGA | 2. CO2 acceptor in C3 plants |
| R. RuBisCO | 3. Carboxylating enzyme in C3 plants |
| S. NADPH | 4. Reducing power for the Calvin cycle |
- P-2, Q-1, R-3, S-4
- P-3, Q-1, R-2, S-4
- P-2, Q-3, R-1, S-4
- P-1, Q-2, R-3, S-4
General
✓✗The reaction centres of PS I and PS II differ in their
- number of electrons they can accept
- pigment, one being chlorophyll a and the other chlorophyll b
- location, one in the stroma and the other in the lumen
- wavelength of maximum absorption, 700 nm and 680 nm