विस्तृत व्याख्या:

Comparison Between Eukaryotes and Prokaryotes (प्रोकैरियोट बनाम यूकेरियोट):

• Eukaryotic-exclusive traits:
• Mitosis: True spindle-mediated nuclear division with chromosome condensation is unique to eukaryotes (prokaryotes lack a true nucleus and divide by binary fission).
• Phagocytosis / Endocytosis: Engulfment of large particles via cytoskeletal and membrane remodeling occurs only in eukaryotic cells; prokaryotes have rigid cell walls and lack the requisite endomembrane machinery.
• Nucleolus: The specialized subnuclear ribosome biogenesis factory exists inside the membrane-bound eukaryotic nucleus (prokaryotes lack both a nucleus and nucleoli).
• Prokaryotic traits:
• 70S ribosomes: Standard in prokaryotes (though also found inside eukaryotic mitochondria/chloroplasts, eukaryotic cytoplasm contains 80S ribosomes).
• Binary fission: Primary mode of prokaryotic asexual division.

विस्तृत व्याख्या:

Ethanol Fermentation by Saccharomyces cerevisiae (यीस्ट द्वारा एथेनॉल किण्वन):

• Statement (I) is CORRECT: Brewer's/baker's yeast (Saccharomyces cerevisiae) has been utilized for millennia and remains the dominant industrial workhorse organism for large-scale bioethanol fuel and alcoholic beverage production owing to its high ethanol tolerance ($\gt 12\%\text{ v/v}$) and rapid fermentation kinetics.
• Statement (II) is CORRECT: Under anaerobic/fermentative conditions, S. cerevisiae metabolizes hexose sugars (glucose, fructose) to pyruvate via the classical Embden-Meyerhof-Parnas (EMP) glycolytic pathway. Pyruvate is subsequently decarboxylated to acetaldehyde by pyruvate decarboxylase and reduced to ethanol by alcohol dehydrogenase with regeneration of $\text{NAD}^+$.

विस्तृत व्याख्या:

Sterilization and Disinfection Mechanisms (निर्जर्मीकरण एवं विसंक्रमण की विधियाँ):

• Discontinuous heating $\rightarrow$ (III). Tyndallization: Fractional steam sterilization developed by John Tyndall involving heating at $100^\circ\text{C}$ for 20–30 minutes on three successive days to allow heat-resistant bacterial endospores to germinate into heat-sensitive vegetative cells in between.
• Destruction of all viable forms including spores $\rightarrow$ (IV). Steam sterilization under pressure: Autoclaving at $121^\circ\text{C}$ ($15\text{ psi}$) for 15–20 minutes completely destroys all vegetative cells, viruses, and highly resistant bacterial endospores.
• Ionization of biological molecules $\rightarrow$ (II). Gamma rays: High-energy ionizing radiation produces hydroxyl radicals ($\text{OH}^\bullet$) from water, shattering DNA strands and biological macromolecules.
• Pyrimidine dimerization $\rightarrow$ (I). UV rays: Non-ionizing UV-C radiation ($260\text{ nm}$) causes formation of covalent thymine-thymine (cyclobutane pyrimidine) dimers in DNA, halting transcription and replication.

Matching sequence: (A) - (III), (B) - (IV), (C) - (II), (D) - (I).
Correct Answer: Option 4.