NEET Biology: Photosynthesis phases and pigments Practice Questions
15 free multiple-choice questions on Photosynthesis phases and pigments (Plant Physiology) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. In the Calvin cycle, what molecule is fixed by the enzyme RuBisCO to initiate the synthesis of organic molecules?
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Correct answer: C — Carbon Dioxide (CO₂)
Carbon dioxide (CO₂) is the inorganic carbon source that is fixed by the enzyme RuBisCO to start the process of synthesizing glyceraldehyde-3-phosphate (G3P).
Q2. Which of the following pigments is responsible for the primary absorption of red and blue light energy in photosynthesis?
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Correct answer: C — Chlorophyll
Chlorophyll strongly absorbs light in the blue and red regions of the visible spectrum, making it the most effective pigment for photosynthesis.
Q3. Which of the following pigments is primarily responsible for the initial absorption of light energy and the initiation of the light-dependent reactions during photosynthesis?
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Correct answer: C — Chlorophyll a
Chlorophyll a is the primary photosynthetic pigment responsible for capturing light energy and initiating the light-dependent reactions in oxygenic photosynthesis.
Q4. In which part of the chloroplast does the light-dependent reaction primarily occur?
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Correct answer: D — Thylakoid membrane
The light-dependent reactions occur on the thylakoid membranes embedded within the chloroplasts.
Q5. The light-dependent reactions of photosynthesis ultimately produce which of the following energy-carrying molecules?
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Correct answer: B — ATP and NADPH
The main outputs of the light-dependent reactions are the energy carriers ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).
Q6. Which of the following stages of photosynthesis occurs in the stroma of the chloroplast?
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Correct answer: D — Light-independent reactions (Calvin cycle)
The Light-independent reactions, specifically the Calvin cycle, take place in the stroma of the chloroplast, where CO₂ fixation occurs.
Q7. Which of the following substances acts as the final electron acceptor in the electron transport chain during photosynthesis?
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Correct answer: D — Oxygen (O₂)
Oxygen acts as the final electron acceptor in the photosynthetic electron transport chain, combining with protons to form water.
Q8. Which molecule is fixed during the Calvin cycle to produce glucose?
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Correct answer: A — CO₂
Carbon dioxide (CO₂) is fixed and subsequently reduced using the energy supplied by ATP and reducing power from NADPH to synthesize carbohydrates.
Q9. Which pigment is primarily responsible for capturing light energy during the initial phase of photosynthesis?
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Correct answer: D — Chlorophyll
Chlorophyll is the main pigment located in the thylakoid membranes of the chloroplasts and is essential for driving the light-dependent reactions.
Q10. The stroma of the chloroplast is the site where which phase of photosynthesis occurs?
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Correct answer: D — Light-independent reactions (Calvin Cycle)
The stroma is the fluid-filled space within the chloroplast where the Calvin cycle (light-independent reactions) takes place, utilizing the ATP and NADPH produced in the thylakoids.
Q11. What is the main energy currency produced during the light-dependent reactions of photosynthesis?
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Correct answer: D — ATP and NADPH
The light-dependent reactions generate ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are the energy carriers.
Q12. What is the immediate energy carrier produced during the light-dependent reactions that is used to power the synthesis of sugars in the Calvin cycle?
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Correct answer: B — NADPH
The light-dependent reactions convert light energy into chemical energy in the form of ATP (Adenosine Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate), which are the energy carriers passed to the Calvin cycle.
Q13. What is the primary source of electrons for the reduction of NADP⁺ during photosynthesis?
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Correct answer: A — Water (H₂O)
Water is split during the light reactions to provide the electrons necessary to reduce NADP⁺ to NADPH.
Q14. Carotenoids, such as carotene, function primarily as what in relation to photosynthesis?
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Correct answer: D — Antioxidants and accessory pigments
Carotenoids act as accessory pigments that help capture light energy and protect the photosynthetic machinery from oxidative damage.
Q15. The primary energy-carrying molecules produced during the light-dependent reactions are:
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Correct answer: A — ATP and NADPH
The light-dependent reactions convert light energy into chemical energy, resulting in the production of ATP (Adenosine Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate), which power the next stage.
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