By studying purple sulphur bacteria and green sulphur bacteria, who was the first scientist to demonstrate, in 1931, that photosynthesis is a light-dependent redox reaction in which hydrogen from an oxidizable compound reduces carbon dioxide to cellular materials?
1. Robert Hill
2. C. B. van Neil
3. Arnon
4. Jan Ingenhousz
1. Robert Hill
2. C. B. van Neil
3. Arnon
4. Jan Ingenhousz
Subtopic: Historical View: Experiments |
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Consider the given two statements:
| Assertion (A): | C4 plants are more suited to hot climates than C3 plants. |
| Reason(R): | They do not close their stomata in hot, dry weather. |
| 1. | (A) is True but (R) is False |
| 2. | Both (A) and (R) are True and (R) correctly explains (A) |
| 3. | Both (A) and (R) are True and but (R) does not correctly explain (A) |
| 4. | (A) is False but (R) is True |
Subtopic: C4 Cycle (Hatch & Slack Pathway) |
67%
From NCERT
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Consider the given two statements:
| Assertion (A): | The Calvin cycle actually occurs only in the dark or during night time. |
| Reason (R): | The Calvin cycle is also called as ‘Dark’ reactions. |
| 1. | (A) is True but (R) is False |
| 2. | Both (A) and (R) are True and (R) correctly explains (A) |
| 3. | Both (A) and (R) are True and but (R) does not correctly explain (A) |
| 4. | (A) is False but (R) is True |
Subtopic: Dark Reaction : Calvin Cycle |
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From NCERT
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Regarding ATP synthase involved in chemiosmosis in chloroplasts:
| I: | The component CF0 is embedded in the thylakoid membrane. |
| II: | The component CF1 protrudes on the outer surface of the thylakoid membrane on the side that faces the stroma. |
| 1. | Only I is correct |
| 2. | Only II is correct |
| 3. | Both I and II are correct |
| 4. | Both I and II are incorrect |
Subtopic: Chemiosmotic hypothesis |
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Consider the two given statements:
| Assertion (A): | The cyclic flow hence, results only in the synthesis of ATP, but not of NADPH + H+. |
| Reason (R): | The excited electron does not pass on to NADP+ but is cycled back to the PS I complex through the electron transport chain. |
| 1. | Both (A) and (R) are True and (R) correctly explains (A) |
| 2. | (A) is True but (R) is False |
| 3. | (A) is False but (R) is True |
| 4. | Both (A) and (R) are True but (R) does not explain (A) |
Subtopic: Light Reaction: Photophosphorylation |
87%
From NCERT
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Given below are two statements:
In the light of the above statements, choose the correct answer from the options given below :
| Statement I: | The primary CO2 acceptor in C4 plants is oxaloacetate and is found in the mesophyll cells |
| Statement II: | Mesophyll cells in C4 plants carry out Calvin cycle. |
| 1. | Statement I is incorrect but Statement II is correct |
| 2. | Both Statement I and Statement II are correct |
| 3. | Both Statement I and Statement II are incorrect |
| 4. | Statement I is correct but Statement II is incorrect |
Subtopic: C4 Cycle (Hatch & Slack Pathway) |
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Van Niel, based on his studies of purple and green bacteria, demonstrated that photosynthesis is essentially a light-dependent reaction in which hydrogen from a suitable oxidisable compound reduces CO2 to carbohydrates. This can be expressed by:
\(2 \mathrm{H}_2 \mathrm{~A}+\mathrm{CO}_2 \xrightarrow{\text { Light }} 2 \mathrm{~A}+\mathrm{CH}_2 \mathrm{O}+\mathrm{H}_2 \mathrm{O}\)
Compare this with the correct equation for photosynthesis:
\(6 \mathrm{CO}_2+12 \mathrm{H}_2 \mathrm{O} \xrightarrow{\text { Light }} \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+6 \mathrm{H}_2 \mathrm{O}+6 \mathrm{O}_2\)
Based on the comparison, which of the following will be correct?
1. Only I and II
2. Only I and III
3. Only II and III
4. I, II and III
\(2 \mathrm{H}_2 \mathrm{~A}+\mathrm{CO}_2 \xrightarrow{\text { Light }} 2 \mathrm{~A}+\mathrm{CH}_2 \mathrm{O}+\mathrm{H}_2 \mathrm{O}\)
Compare this with the correct equation for photosynthesis:
\(6 \mathrm{CO}_2+12 \mathrm{H}_2 \mathrm{O} \xrightarrow{\text { Light }} \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+6 \mathrm{H}_2 \mathrm{O}+6 \mathrm{O}_2\)
Based on the comparison, which of the following will be correct?
| I: | In green plants H2O is the hydrogen donor and is oxidised to O2. |
| II: | Some organisms do not release O2 during photosynthesis. |
| III: | O2 evolved by the green plant comes from H2O, not from carbon dioxide. |
1. Only I and II
2. Only I and III
3. Only II and III
4. I, II and III
Subtopic: Introduction | Historical View: Experiments |
78%
From NCERT
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Consider the two statements:
| Statement I: | Chloroplasts align perpendicular to the walls of mesophyll cells when intensity of light is minimum, to get more and more of light. |
| Statement II: | Chloroplasts align parallel to the walls of mesophyll cells when intensity of light is minimum, to get more and more of light. |
| 1. | Statement I is correct; Statement II is correct |
| 2. | Statement I is incorrect; Statement II is correct |
| 3. | Statement I is correct; Statement II is incorrect |
| 4. | Statement I is incorrect; Statement II is incorrect |
Subtopic: Chloroplast Structure |
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The given diagram shows action spectrum of photosynthesis superimposed on absorption spectrum of chlorophyll a. Identify the correct inference that can be drawn:
1. Only I and II
2. Only I and III
3. Only II and III
4. I, II and III
| I: | Chlorophyll a is the chief pigment associated with photosynthesis. |
| II: | Most of the photosynthesis takes place in the blue and red regions of the spectrum. |
| III: | No pigments other than chlorophyll a are involved in absorbing sunlight in green plants. |
2. Only I and III
3. Only II and III
4. I, II and III
Subtopic: Pigments |
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Consider the given two statements:
| Assertion: | The whole scheme of transfer of electrons, during light reactions, is called the Z scheme. |
| Reason: | Z shape is formed when all the carriers are placed in a sequence on a redox potential scale. |
| 1. | Both Assertion and Reason are true but Reason is not the correct explanation of Assertion. |
| 2. | Assertion is true but Reason is false. |
| 3. | Both Assertion and Reason are true and Reason correctly explains Assertion. |
| 4. | Assertion is false but Reason is true. |
Subtopic: Light Reaction: Electron Transport |
66%
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