वनस्पति विज्ञान – Botany – Botany MCQ
वनस्पति विज्ञान – Botany – CEE प्रवेश
Botany · Medical Entrance (CEE) – Physics, Chemistry, Biology & MAT · ४०७ प्रश्न
४०७ प्रश्न उपलब्ध। मोड छान्नुहोस्:
वनस्पति विज्ञान – Botany: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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The plant hormone that induces and maintains dormancy in seeds and buds is:
सही उत्तर: ख) abscisic acid
ABA promotes seed and bud dormancy, helping seeds survive dry or cold periods; gibberellins break dormancy.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Zeatin, a naturally occurring cytokinin, was isolated from:
सही उत्तर: ख) corn (maize) kernels and coconut milk
Natural cytokinin-like activity was found in maize kernels and coconut milk (zeatin); kinetin came from autoclaved herring sperm DNA and auxin was first isolated from human urine.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Ethephon, widely used in agriculture to hasten fruit ripening, acts by:
सही उत्तर: घ) releasing ethylene
Ethephon is absorbed by the plant and slowly releases ethylene, which promotes ripening, flowering in pineapple and abscission.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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When an organic acid such as malic acid is the respiratory substrate, the respiratory quotient (RQ) is:
सही उत्तर: घ) more than 1 (about 1.33)
C₄H₆O₅ + 3O₂ → 4CO₂ + 3H₂O; RQ = 4/3 ≈ 1.33. Oxygen-rich substrates give RQ above 1.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In aerobic respiration of eukaryotes, the oxidative decarboxylation of pyruvic acid to acetyl CoA takes place in the:
सही उत्तर: क) mitochondrial matrix
Pyruvate enters the mitochondrion, where pyruvate dehydrogenase converts it to acetyl CoA, releasing CO₂ and forming NADH.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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C₄ plants such as maize show chloroplast dimorphism, in which the chloroplasts of the bundle sheath cells are:
सही उत्तर: ग) large and agranal (lacking well-developed grana)
Mesophyll chloroplasts are granal and carry out light reactions; the large bundle-sheath chloroplasts lack grana and contain RuBisCO for the Calvin cycle.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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To make one molecule of glucose through the Calvin cycle, a C₃ plant requires:
सही उत्तर: ग) 18 ATP and 12 NADPH
Fixing each CO₂ needs 3 ATP and 2 NADPH; six turns (6 CO₂) are needed for one glucose, i.e. 18 ATP and 12 NADPH.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In cyclic photophosphorylation:
सही उत्तर: क) only photosystem I is involved and only ATP is formed
Electrons from PS I return to it via the electron transport chain, producing ATP but no NADPH and no O₂.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Besides acting as accessory pigments, carotenoids in chloroplasts:
सही उत्तर: ग) protect chlorophyll from photo-oxidation
Carotenoids absorb additional wavelengths and pass energy to chlorophyll a; they also protect chlorophyll from damage by excess light (photo-oxidation).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The micronutrient required by plants for the synthesis of the hormone auxin is:
सही उत्तर: क) zinc
Zinc activates enzymes such as carboxylases and is needed for auxin synthesis; molybdenum is part of nitrogenase.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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