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 mineral element whose best-defined function is in the splitting (photolysis) of water to release oxygen during photosynthesis is:
सही उत्तर: क) manganese
Manganese is a component of the oxygen-evolving complex of photosystem II, where water is split.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Deficiency symptoms of nitrogen and magnesium appear first in the older leaves because these elements are:
सही उत्तर: ग) mobile and are moved from older to younger leaves
Mobile elements such as N, K and Mg are withdrawn from senescing older tissues and sent to young ones, so older leaves show deficiency first.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Substances such as phenyl mercuric acetate and abscisic acid, which reduce transpiration by causing stomatal closure, are called:
सही उत्तर: ख) antitranspirants
Antitranspirants reduce water loss from leaves, for example by closing stomata (PMA, ABA) or by forming a film over the leaf surface.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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When the stem of a well-watered herbaceous plant is cut near the base in the morning, sap oozes out of the stump. This is evidence of:
सही उत्तर: क) root pressure
Active absorption of ions makes water move into the xylem of the root, building a positive root pressure that pushes sap out of the cut stem.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A plant cell placed in pure water becomes fully turgid. At this stage:
सही उत्तर: ख) its water potential is zero, as ψp equals −ψs
Water enters until ψw of the cell equals that of pure water (zero); then ψp = −ψs, so ψw = ψs + ψp = 0.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Dry seeds and raisins swell up when placed in water. This phenomenon is called:
सही उत्तर: घ) imbibition
Imbibition is the absorption of water by hydrophilic colloids such as cellulose, starch and proteins, causing swelling.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The water potential (ψw) of a plant cell is related to its solute potential (ψs) and pressure potential (ψp) by:
सही उत्तर: ख) ψw = ψs + ψp
Water potential is the sum of solute potential (always negative) and pressure potential (usually positive in a turgid cell).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In the dorsiventral leaf of a typical dicot, stomata are usually:
सही उत्तर: ग) more numerous on the lower (abaxial) surface
Dicot leaves usually have more stomata on the lower surface, which reduces water loss; isobilateral monocot leaves have them on both surfaces.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In roots, most water and minerals are absorbed through the root hairs, which are outgrowths of the:
सही उत्तर: क) epidermal cells
Root hairs are unicellular tubular extensions of epidermal cells in the zone of maturation, greatly increasing the absorbing surface.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Phloem parenchyma is absent in the phloem of:
सही उत्तर: क) most monocotyledons
Phloem parenchyma is present in most dicots, gymnosperms and pteridophytes, but is absent in most monocots.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
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