Photosynthesis in Plants AIIMS AIPMT PMT NEET JIPMER MCAT Questions

1. Which of the following graphs correctly depicts the rate of photosynthesis of sun plant (P) and shade plant (Q)?



















2. When two plants L and M were exposed to different light intensities and temperatures, they showed changes in their rates of photosynthesis, which have been represented in the following graph.







The graph indicates that
(a) Plant L is a C3 plant for which the light saturation point is 100% of full sunlight.
(b) Plant M is a C4 plant for which the optimum temperature is around 20°C.
(c) Plant M is a C3 plant which is more affected at higher temperature and higher light intensity as compared to plant L.
(d) Plant L is a C4 plant and cannot function at light intensities above the saturation point.
3. When wheat and sugarcane leaves are fed with radioactive ,4CO2, in which molecule would the radioactivity appear first in these plants?

Wheat Sugarcane
(a) 3-Phosphoglycerate Oxaloacetate
(b) 3-Phosphoglycerate 3-Phosphoglycerate
(c) Oxaloacetate Oxaloacetate
(d) Malate 3-Phosphoglycerate

4. Given table shows the C02 compensation point and optimum C02 concentration for photosynthesis for C3 and C4 plants.

C3 Plants C4 Plants
CO2 compensation point 25-100 ppm A
Optimum CO2 concentration B 360 ppm

Select the correct values for A and B.

(a) 0-50 ppm 300 ppm
(b) 0-10 ppm 450 ppm
(c) 100-150 ppm 250 ppm
(d) 100-110 ppm 290 ppm

5. Warburg effect refers to
(a) decreased photosynthetic rate at very high 02 concentration
(b) increased photosynthetic rate at very high 02 concentration
(c) decreased photosynthetic rate at very low 02 concentration
(d) increased photosynthetic rate at very low 02 concentration.
6. During fixation of one molecule of C02 by C3 plants, number of ATP and NADPH2 required are
(a) 3 ATP and 2 NADPH2
(b) 5 ATP and 2 NADPH2
(c) 12 ATP and 12 NADPH2
(d) 2 ATP and 3 NADPH2

7. Select the incorrect pair.
(a) 2-carbon compound – Aspartic acid
(b) 3-carbon compound – PGA
(c) 4-carbon compound – Malic acid
(d) 5-carbon compound – RuBP













9. Refer to the given reaction.
2H20 -» 4H+ + 02 + 4e
Where does this reaction take place in the chloroplasts of plants?
(a) Outer surface of thylakoid membrane
(b) Inner surface of thylakoid membrane
(c) In the matrix (stroma)
(d) Intermembrane space
10. Select the incorrect statement as far as kranz anatomy is concerned.
(a) Undifferentiated mesophyll occurs in concentric layers around vascular bundles.
(b) Centrifugal chloroplasts are present in bundle sheath cells.
(c) Large sized bundle sheath cells are arranged in a wreath-like manner in one to several layers.
(d) Chloroplasts of bundle sheath cells possess well- developed grana lamellae.
11. In an experiment demonstrating the evolution of oxygen in Hydrilla, sodium bicarbonate is added to
water in the experimental set-up. What would happen if all other conditions are favourable?
(a) Amount of oxygen evolved decreases as the availability of carbon dioxide increases.
(b) Amount of oxygen evolved increases as
carbon dioxide in water is absorbed by sodium bicarbonate
(c) Amount of oxygen evolved decreases as
carbon dioxide in water is absorbed by sodium bicarbonate
(d) Amount of oxygen evolved increases as the availability of carbon dioxide increases.
12. Identify A in the given figure and choose a correct option.







(a) PC (b) FRS (c) PQ (d) Cyf-93
13. Rate of photosynthesis is low in herbs, shrubs as compared to sun plants because
(a) herbs, shrubs receive more red light
(b) herbs, shrubs receive more blue light
(c) herbs, shrubs receive more green light
(d) herbs, shrubs receive more white light.
14. C4 plant minimises the photorespiration because C4 plants
(a) use PEPcase to initiate C02 fixation
(b) do not carry out the Calvin cycle in low C02 level
(c) exclude Calvin cycle
(d) show photorespiration.
15. Protons produced by the splitting of water in light reaction of photosynthesis accumulate within the
(a) lumen of thylakoids
(b) intermembrane space of chloroplast
(c) stroma of chloroplast
(d) outside the lumen of thylakoids.
True or False type questions
16. In photorespiratory pathway, there is minimum synthesis of ATP or NADPH.
17. Calvin pathway occurs in all mesophyll cells of both C3 and C4 plants.
18. Chemiosmosis requires a membrane, an electron pump, electron gradient and ATPase.
19. RuBisCO binds to both CO2 and O2, with the same affinity.
20. Proton accumulation in photosynthesis and respiration is same, i.e., intermembrane space.
21. The electrons removed from photosystem I are provided by photosystem II.
22. Engelmann demonstrated that photosynthesis is essentially a light dependent reaction.
23. Photosynthesis occurs only in green leaves of plants.
24. In PS I the reaction centre chlorophyll a has an absorption peak at 680 nm, while in PS II, absorption maxima is at 700 nm.
25. ATPase consists of two parts, one called F, is embedded in the membrane and the other called F0, protrudes on the outer surface of thylakoid membrane.

26. Match Column-I with Column-ll and select the correct option from codes given below.

Column-I Column-II
A. P700 (i) Oxygen evolving complex
B. Carotene ii) RuBP
C. Carboxydismutase (iii) PEP
D. Photorespiration (iv) Phosphoglycolate
E. C4 plant (v) RuBisCO
F. C3 plant (vi) Lycopene
G. P680 (vii)Cydic flow of electrons

27. Match Column-I with Column-ll. There may be more than one correct matches for items in Column-I.

Column-I Column-II
A. Hatch Slack pathway (i) Pennisetum
B. Calvin cycle (ii) Chlorella
C. C2 cycle (iii) Scenedesmus
D. CAM (iv) Peroxisome
E. Solarisation (v) Pineapple
F. Photosynthetic rate (vi) Photooxidation
G. CO2 compensation (vii) Red drop effect
(viii) 25-100 ppm – C3
(ix) 0-10 ppm-C4 plants
(x) Emerson
(xi) Photoinhibition
(xii) Vanilla
(xiii) Mitochondrion
(xiv) Panicum

28. (A) Complete the given passage with appropriate words or phrases.
When only (i) is functional, the electron is circulated within the photosystem and (ii) occurs. A possible location where this could be happening is in the (iii). While the membrane or lamellae of the grana have both (iv) and (v) the stroma lamellae membranes lack (vi) as well as (vii) enzyme.
(B) Read the passage and correct the errors, wherever present.
C4 plants show saturation at about 260 u/L, while C3 show saturation below 450 u/L.
The light reactions are temperature controlled, while the dark reactions are affected to a much lesser extent.

Assertion & Reason Questions
In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of the statements, mark the correct answer as:
(a) if both A and R are true and R is the correct explanation of A
(b) if both A and R are true but R is not the correct explanation of A
(c) if A is true but R is false
(d) if both A and R are false.
29. Assertion : The rate of photosynthesis in bright light is much higher in sun plants, than in shade plants.

Reason : The sun plants contain more chlorophyll as compared to shade plants.
30. Assertion : Euphorbia maculata is a C4 plant. Reason : Euphorbia corollata is a C3 plant.
31. Assertion : C4 plants are adapted to dry, tropical regions.
Reason : These plants use C3 pathway as the main biosynthetic pathway.
32. Assertion : Phycobilins are found in phycobilisomes attached to the thylakoids.
Reason: They are found in blue, green, red and green algae.
33. Assertion : Alongwith chlorophyll a, the carotenoids are called accessory pigments.
Reason: They hand over the energy absorbed by them to chlorophyll b.
34. Assertion : From plastocyanin, the electron is picked up by the trap centre P700 of photosystem II.
Reason : The electron is received by plastocyanin from plastoquinone.
35. Assertion : Carbon dioxide can be fixed in the dark by previously illuminated green cells.
Reason : The reactions do not require light, and use assimilatory power from the light reaction.
36. Assertion : Photosynthetic carbon reduction cycle requires RuBP as acceptor of carbon dioxide and RuBisCO as enzyme.
Reason : RuBisCO has a rapid turnover of nearly 300 molecules per second.
37. Assertion : C4 plants have overcome the problem of photorespiration.
Reason : Light reaction in C4 plants occurs in bundle sheath cells and RuBisCO mediated C02 fixation in mesophyll cells.
38. Assertion : The range of photosynthetically active radiation – PAR lies between 400-700 nm.
Reason: Red light favours carbohydrate accumulation while blue light stimulates protein synthesis.

39. Refer to the figure given below and identify A, B,C, D and E













40. Fill in the blanks using given letters and appropriate words / phrases.
(a) While going over (i) the electron energises passage of protons to create a proton gradient for synthesis of ATP from ADP and inorganic phosphate.
(b) (ii) also hands electron to photocentre P700 of PS I in non-cydic photophosphorylation.
(c) In the given figure of cyclic photophosphorylation, there is no (iii) of water, no evolution of (iv) and no synthesis of (v) . as in noncydic photophosphorylation.


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