Category: Daily Practice MCQs
Agriculture Daily Practice MCQs – 63
By Agritests |
27 Jul, 2026
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1. In C₄ plants, the primary role of bundle sheath cells is to: A. Carry out photolysis of water B. Concentrate CO₂ around Rubisco, minimizing photorespiration C. Synthesize ATP exclusively through cyclic photophosphorylation D. Oxidize glycolate during photorespiration Show Answer Answer: B. Concentrate CO₂ around Rubisco, minimizing photorespiration Explanation: Bundle sheath cells decarboxylate C₄ acids, […]
Agriculture Daily Practice MCQs – 62
By Agritests |
27 Jul, 2026
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1. During cyclic electron transport in chloroplasts, ATP is synthesized without the net production of: A. ADP and Pi B. Ferredoxin C. NADPH and O₂ D. Plastoquinone Show Answer Answer: C. NADPH and O₂ Explanation: Cyclic photophosphorylation involves only Photosystem I. Electrons cycle back through the electron transport chain, generating ATP without producing NADPH or […]
Agriculture Daily Practice MCQs – 61
By Agritests |
27 Jul, 2026
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1. During the Mehler reaction (water-water cycle) in chloroplasts, molecular oxygen serves primarily as: A. The final electron donor to Photosystem II B. An alternative terminal electron acceptor at Photosystem I C. The substrate for RuBisCO oxygenase activity D. The electron donor for ferredoxin reduction Show Answer Answer: B. An alternative terminal electron acceptor at […]
Agriculture Daily Practice MCQs – 60
By Agritests |
27 Jul, 2026
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1. Which Calvin cycle enzyme is specifically activated in the light through the ferredoxin-thioredoxin regulatory system, thereby enhancing photosynthetic carbon assimilation? A. Ribulose-5-phosphate Isomerase B. Fructose-1,6-bisphosphatase C. Hexokinase D. Phosphoglucomutase Show Answer Answer: B. Fructose-1,6-bisphosphatase Explanation: Chloroplastic fructose-1,6-bisphosphatase is activated by thioredoxin reduced through the ferredoxin-thioredoxin system, allowing Calvin cycle enzymes to function efficiently in […]
Agriculture Daily Practice MCQs – 59
By Agritests |
27 Jul, 2026
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1. In C4 photosynthesis, which enzyme specifically catalyzes the decarboxylation of malate within the bundle sheath chloroplasts of NADP-malic enzyme (NADP-ME) subtype plants such as maize? A. Phosphoenolpyruvate Carboxylase (PEPC) B. NADP-Malic Enzyme (NADP-ME) C. Pyruvate Orthophosphate Dikinase (PPDK) D. Carbonic Anhydrase Show Answer Answer: B. NADP-Malic Enzyme (NADP-ME) Explanation: In NADP-ME type C₄ plants […]
Agriculture Daily Practice MCQs – 58
By Agritests |
27 Jul, 2026
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1. Which Calvin cycle enzyme is specifically activated in the light through the ferredoxin-thioredoxin regulatory system, thereby enhancing photosynthetic carbon assimilation? A. Ribulose-5-phosphate Isomerase B. Fructose-1,6-bisphosphatase C. Hexokinase D. Phosphoglucomutase Show Answer Answer: B. Fructose-1,6-bisphosphatase Explanation: Chloroplastic fructose-1,6-bisphosphatase is activated by thioredoxin reduced through the ferredoxin-thioredoxin system, allowing Calvin cycle enzymes to function efficiently in […]
Agriculture Daily Practice MCQs – 57
By Agritests |
27 Jul, 2026
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1. Which photosynthetic enzyme possesses both carboxylase and oxygenase activities, making it responsible for photorespiration in C₃ plants? A. Phosphoenolpyruvate Carboxylase (PEPC) B. Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RuBisCO) C. Carbonic Anhydrase D. Malate Dehydrogenase Show Answer Answer: B. Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RuBisCO) Explanation: RuBisCO catalyzes both CO₂ fixation and oxygenation of RuBP. The oxygenase reaction initiates photorespiration, reducing […]
Agriculture Daily Practice MCQs – 56
By Agritests |
27 Jul, 2026
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1. Which enzyme catalyzes the reduction of nitrate (NO₃⁻) to nitrite (NO₂⁻) during nitrate assimilation in higher plants? A. Nitrite Reductase B. Nitrate Reductase C. Nitrogenase D. Glutamate Synthase Show Answer Answer: B. Nitrate Reductase Explanation: Nitrate reductase is the first key enzyme of nitrate assimilation, reducing nitrate to nitrite in the cytoplasm before further […]
Agriculture Daily Practice MCQs – 55
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27 Jul, 2026
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1. Which enzyme is responsible for the oxidation of ammonium (NH₄⁺) to nitrite (NO₂⁻) during the first step of nitrification in soils? A. Nitrite Oxidoreductase B. Ammonia Monooxygenase C. Nitrogenase D. Nitrate Reductase Show Answer Answer: B. Ammonia Monooxygenase Explanation: Ammonia monooxygenase (AMO), present in ammonia-oxidizing bacteria and archaea, catalyzes the first and rate-limiting step […]
Agriculture Daily Practice MCQs – 54
By Agritests |
27 Jul, 2026
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1. Which enzyme is responsible for the conversion of atmospheric nitrogen (N₂) into ammonia during biological nitrogen fixation? A. Nitrate Reductase B. Nitrite Reductase C. Nitrogenase D. Glutamine Synthetase Show Answer Answer: C. Nitrogenase Explanation: Nitrogenase is the enzyme complex found in nitrogen-fixing microorganisms that reduces atmospheric nitrogen (N₂) to ammonia (NH₃), an energy-intensive process […]