जीव विज्ञान – Zoology – Zoology MCQ
जीव विज्ञान – Zoology – CEE प्रवेश
Zoology · Medical Entrance (CEE) – Physics, Chemistry, Biology & MAT · ४०८ प्रश्न
४०८ प्रश्न उपलब्ध। मोड छान्नुहोस्:
जीव विज्ञान – Zoology: 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 sino-atrial node (SAN), often referred to as the 'pacemaker', of the human heart initiates electrical impulses that trigger heart contractions. What is the primary mechanism responsible for this rhythmic activity?
सही उत्तर: ग) Automatic Depolarization of SA and AV Nodes
The SAN exhibits spontaneous depolarization due to the influx of sodium ions, initiating an action potential that spreads throughout the heart, leading to rhythmic contractions. The other options describe secondary responses or conduction pathways within the heart.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which endocrine cell within the testis directly produces testosterone?
सही उत्तर: ख) Leydig Cells
Leydig cells are specifically responsible for synthesizing and secreting testosterone, which is crucial for male sexual development and function. Sertoli cells provide support to developing sperm cells.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In mammalian nephron, nearly all essential nutrients (around 98%) along with approximately 70-80% of filtered electrolytes are reabsorbed in which region?
सही उत्तर: ख) Proximal Convoluted Tubule
The proximal convoluted tubule is the primary site for nutrient and electrolyte reabsorption from glomerular filtrate due to its high density of microvilli and active transport mechanisms. The glomerulus filters, and the loop of Henle plays a role in water regulation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The type of cell junction found between adjacent epithelial cells that tightly controls permeability is termed as:
सही उत्तर: ग) Tight Junctions
Tight junctions are specialized cell junctions that form a seal between epithelial cells, preventing the passage of substances. Gap junctions allow communication between cells, while desmosomes and hemidesmosomes provide mechanical strength.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which organelle is responsible for degrading damaged or worn-out cellular components within a cell?
सही उत्तर: ख) Lysosome
The lysosome is the primary degradation compartment of the cell, containing enzymes that break down lipids, carbohydrates, proteins and nucleic acids. The other organelles listed – mitochondria, ribosomes, and the endoplasmic reticulum – have different, distinct functions within the cell.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The process of autophagy involves the degradation and recycling of damaged cellular components. Which organelle plays a central role in this process? (A) Endoplasmic Reticulum (B) Golgi Apparatus (C) Lysosome (D) Peroxisome
सही उत्तर: ग) Lysosome
Lysosomes contain enzymes that break down cellular waste products and damaged organelles – this is the core function of autophagy. The other organelles have distinct roles in protein synthesis and modification.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following is a key characteristic distinguishing prokaryotic cells from eukaryotic cells? (A) Presence of membrane-bound organelles. (B) Containment of DNA within a nucleus. (C) Smaller size compared to eukaryotic cells. (D) Ribosomes are present in both types of cells.
सही उत्तर: ख) Containment of DNA within a nucleus.
Eukaryotic cells possess complex internal structures like the nucleus and mitochondria, enclosed by membranes. Prokaryotic cells lack these membrane-bound organelles, and their DNA is not contained within a nucleus.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following cellular structures is primarily responsible for maintaining cell volume by regulating the movement of water in and out of the cell? (A) Ribosomes (B) Mitochondria (C) Cell Membrane (Plasma Membrane) (D) Nucleus
सही उत्तर: ग) Cell Membrane (Plasma Membrane)
The cell membrane’s phospholipid bilayer and associated proteins control the passage of water molecules into and out of the cell through osmosis. Ribosomes are involved in protein synthesis, mitochondria produce energy, and the nucleus contains genetic material.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The process of oogenesis (formation of female gametes) is initiated during which phase of the menstrual cycle? (A) Menstruation (B) Follicular Phase (C) Ovulation (D) Luteal Phase
सही उत्तर: ग) Ovulation
Oogenesis begins during the follicular phase when primordial follicles develop into primary oocytes. Menstruation marks the end of a cycle, ovulation releases the mature egg, and the luteal phase follows ovulation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following statements best describes the function of cilia in respiratory epithelium? (A) They facilitate gas exchange between air and blood. (B) They propel mucus and trapped particles towards the pharynx for removal. (C) They provide structural support to the epithelial cells. (D) They enhance nutrient absorption from the inhaled air.
सही उत्तर: ख) They propel mucus and trapped particles towards the pharynx for removal.
Cilia are tiny hair-like structures that beat in a coordinated manner to move mucus and debris across the surface of the respiratory tract. Option A is incorrect as gas exchange occurs at alveoli, not cilia. Option C describes cell shape, and option D is incorrect regarding nutrient absorption.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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