Assertion (A): | Except for plants in shade or in dense forests, light is rarely a limiting factor for photosynthesis in nature. |
Reason (R): | Increase in incident light beyond a point causes the breakdown of chlorophyll and a decrease in photosynthesis. |
1. | (A) is True but (R) is False |
2. | Both (A) and (R) are True and (R) explains (A) |
3. | Both (A) and (R) are True but (R) does not explain (A) |
4. | (A) is False but (R) is True |
Assertion (A): | Current availability of CO2 levels is limiting to the C3 plants. |
Reason (R): | Carbon dioxide is the major limiting factor for photosynthesis. |
1. | (A) is True but (R) is False |
2. | Both (A) and (R) are True and (R) explains (A) |
3. | Both (A) and (R) are True but (R) does not explain (A) |
4. | (A) is False but (R) is True |
I: | Water stress causes the stomata to close, hence reducing the CO2 availability. |
II: | Water stress also makes leaves wilt, thus, increasing the surface area of the leaves and their metabolic activity as well. |
1. | Only I |
2. | Only II |
3. | Both I and II |
4. | Neither I nor II |
Assertion (A): | Plants that do not use PEP-carboxylase in primary carbon fixation are called C3 plants. |
Reason (R): | C3 plants are so called because, the primary carboxylation reaction, catalyzed by RuBisCO, produces the three-carbon 3-phosphoglyceric acids directly in the Calvin-Benson cycle. |
1. | (A) is True but (R) is False |
2. | Both (A) and (R) are True and (R) explains (A) |
3. | Both (A) and (R) are True but (R) does not explain (A) |
4. | (A) is False but (R) is True |
Assertion (A): | Water molecules appear on both sides of the equation of photosynthesis. |
Reason (R): | The molecules that enter the reaction are not the same molecules that emerge from the reaction. |
1. | Both (A) and (R) are True and (R) correctly explains (A). |
2. | Both (A) and (R) are True but (R) does not correctly explain (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False |
1. | Oxygen | 2. | NADP+ |
3. | Water | 4. | G3P |
1. | Chlorophyll a | 2. | Chlorophyll b |
3. | Xanthophylls | 4. | Carotenoids |
Assertion (A): | Accessory photosynthetic pigments in higher plants enable a wider range of wavelength of incoming light to be utilised for photosynthesis. |
Reason (R): | Accessory pigments protect chlorophyll a from photo-oxidation. |
1. | Both (A) and (R) are True and (R) correctly explains (A). |
2. | Both (A) and (R) are True but (R) does not correctly explain (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Statement I: | The electrons that are removed from photosystem II are replaced by electrons available due to splitting of water. |
Statement II: | The electrons needed to replace those removed from photosystem I are provided by photosystem II. |
1. | Statement I is correct; Statement II is incorrect |
2. | Statement I is correct; Statement II is correct |
3. | Statement I is incorrect; Statement II is incorrect |
4. | Statement I is incorrect; Statement II is correct |