विस्तृत व्याख्या:

Deuteromycota / Fungi Imperfecti (ड्यूटेरोमाईकोटा - अपूर्ण कवक):

• Assertion (A) is TRUE: In mycological classification, Deuteromycetes (Deuteromycotina) are conventionally designated as Fungi Imperfecti (अपूर्ण कवक).
• Reason (R) is TRUE and correctly explains (A): In mycology, the sexual stage (meiotic reproduction) is termed the teleomorph (perfect state), whereas the asexual conidial stage is termed the anamorph (imperfect state). Deuteromycetes are classified as 'imperfect' precisely because only their asexual / anamorphic phase has been observed in nature, with no recognized sexual / teleomorphic stage. When a sexual stage is discovered, the fungus is reclassified into Ascomycota or Basidiomycota.

विस्तृत व्याख्या:

Initiator Amino Acid in Protein Translation (प्रोटीन अनुवाद में प्रारंभिक अमीनो अम्ल):

• In Eubacteria (True Bacteria): Translation initiates with a specialized modified amino acid, N-formylmethionine (fMet), delivered by initiator $\text{tRNA}_f^{\text{Met}}$.
• In Archaea (and Eukaryotes): Translation initiates with unmodified Methionine (Met), carried by initiator $\text{tRNA}_i^{\text{Met}}$.
• Comparison with the Statements:
• Statement (I) erroneously claims Methionine initiates in Eubacteria (False, it is fMet).
• Statement (II) erroneously claims N-formylmethionine initiates in Archaea (False, it is unmodified Met).

विस्तृत व्याख्या:

Symbiotic Nitrogen Fixation (सहजीवी नाइट्रोजन स्थिरीकरण):

• Anabaena: Filamentous cyanobacterium that establishes nitrogen-fixing endosymbioses with the water fern Azolla (Anabaena azollae) and cycad coralloid roots (Anabaena cycadeae).
• Frankia: Nitrogen-fixing actinobacterium that forms actinorhizal root nodules on non-leguminous woody dicots (Alnus, Casuarina).
• Bradyrhizobium: Slow-growing rhizobacterium forming nitrogen-fixing root nodules on soybean (Glycine max) and cowpea.
• Non-symbiotic / non-nitrogen-fixing organisms:
• Azotobacter: Free-living, aerobic, non-symbiotic diazotroph.
• Ulothrix: Filamentous green alga that does not fix nitrogen.

विस्तृत व्याख्या:

Structure and Genome of Tobacco Mosaic Virus (TMV):

• Statement (I) is CORRECT: TMV is a rigid, cylindrical rod-shaped virion measuring $300\text{ nm} \times 18\text{ nm}$ with helical symmetry, comprising 2,130 identical coat protein subunits and RNA as its genetic material.
• Statement (II) is INCORRECT: The genome of TMV is a single-stranded positive-sense RNA (ssRNA) molecule of 6,395 nucleotides, NOT double-stranded.