In succulent plants the stomata open in night and close in d

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

191.

Assertion : The efficiency of C4 plant is more than those of C3 plant.

Reason : C4 plants are more efficient in picking CO2.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are hue but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


192.

Cyclic photophosphorylation involves

  • PS I

  • PS II

  • PS I and PS II

  • P680


193.

The first stable product of Calvin cycle is

  • 3- phosphoglycerate

  • 1, 3 biphosphoglycerate

  • glyceralydehyde - 3 phosphate

  • ribulose - 5 - phosphate


194.

Assertion : Due to pollution atmospheric concentration of CO2 is increasing which will be harmful for C4 plants whereas productivity is going to increase for C3 plants.

Reason : C4 plants have greater efficiency for CO2 as CO2 is fixed by PEP oxygenase.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


Advertisement
195.

PS-II occurs only in

  • stroma

  • granal thylakoids

  • stromal lamella

  • matrix


196.

Which of the following statements is correct

  • Photorespiration is useful process.

  • C4 plants are more efficient than C3 plants.

  • C3 plants are more efficient than C4 plants.

  • Photorespiration is absent in C3 plants but present in C4 plants.


197.

Which of the following is the characteristic of PS-I?

  • It is active only upto 680 nm of light.

  • The reaction centre of PS- I is P680.

  • PS- I is reduced by the electrons released in photolysis of water.

  • PS-I is involved in non-cyclic photophosphorylation.


198.

Assertion : Dark reaction occurs only at night in the stroma of chloroplast.

Reason : CO2 fixation occurs only during C3 cycle.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


Advertisement
Advertisement

199.

In succulent plants the stomata open in night and close in day. Which among the following would be best hypothesis to explain the mechanism of stomatal action in night only.

  • CO2 accumulates, reduces pH, stimulate enzymes resulting in accumulation of sugars.

  • Increase in CO2 concentration, conversion of organic acids into starch resulting in the increased conversion into sugars resulting in K+ transport.

  • Low CO2 concentration accumulates organic acids resulting in the increased concentration of cell sap.

  • CO2 used up, increase pH results in accumulation of sugars.


B.

Increase in CO2 concentration, conversion of organic acids into starch resulting in the increased conversion into sugars resulting in K+ transport.

In CAM plants stomata open at night. In these plants night acidification occurs. i.e., malic acid is
synthesised during night due to incomplete oxidation of carbohydrates.
In night. 2 C 6H12O6+ 3 O2 3 C 4H6O5+ 3H2O
                                             (malic acid)
                                                    
                                leads to opening of stomata

At night malic acid formed in guard cells dissociates into H and malate ions. K ion exchange from subsidiary cells with H ions. Thus due to accumulation of K ions osmotic pressure of guard cells increases, endosmosis occurs and guard cells become turgid due to which stomata opens. The malic acid at clay time breaks into CO2 and pyruvic acid thus increasing the concentration of CO2 in mesophyll cells. This is utilised in Calvin cycle to form sugar which is finally converted into starch.


Advertisement
200.

Chlorenchyma is known to develop in the

  • cytoplasm of Chlorella

  • mycelium of a green mould such as Aspergillus

  • spore capsule of a moss

  • pollen tube of Pinus


Advertisement