Respiration

• Historic Cloned Mammals:
• Cloned Sheep:
• Dolly (1996): First mammal cloned from adult somatic cells.
• Megan and Morag (1995): First cloned sheep from differentiated embryonic cell lines.
• Polly (1997): First transgenic cloned sheep bearing human factor IX gene.
• Xena (2000):
• The world's first cloned pig (porcine), produced from adult granulosa cells via SCNT.
• nalysis:
• (Xena): Correct (Xena is a cloned pig, not a sheep).

Correct option: (2) Xena

• Aerobic Energy Generation:
• Assertion (A): Under aerobic conditions, the tricarboxylic acid (TCA) cycle coupled with the electron transport chain represents the cell's primary catabolic generator of metabolic ATP. (True).
• Reason (R): For each turn of the TCA cycle, oxidation of acetyl-CoA reduces 3 molecules of $NAD^+$ to $NADH$ and 1 molecule of $FAD$ to $FADH_2$. The transfer of electrons from these reduced cofactors through the mitochondrial electron transport chain drives oxidative phosphorylation, producing approximately 10 high-energy ATP equivalents per acetyl-CoA. (True).
• nalysis:
• Both (A) and (R) are correct, and (R) is the correct explanation of (A). Hence, Option 1 is correct.

• Lymphocyte Blastogenesis and Mitogens:
• In whole blood lymphocyte cultures for cytogenetic karyotyping or cell-mediated immune assays:
• Phytohemagglutinin (PHA), a plant lectin extracted from the red kidney bean (Phaseolus vulgaris), binds to surface carbohydrate receptors on T-lymphocytes, acting as a potent polyclonal mitogen that stimulates blast transformation, DNA synthesis, and mitotic cell division.
• nalysis:
• (Phytohemagglutinin): Correct mitogen.

Correct option: (2) Phytohemagglutinin.

• Generation of Transgenic Livestock and Rodents:
• Pronuclear DNA Microinjection (Gordon & Ruddle, 1980):
• Linearized recombinant transgene constructs are injected directly into the male pronucleus of freshly fertilized embryos at the One-Cell Stage (zygote).
• Performing microinjection at the single-cell stage prior to the first mitotic cleavage ensures that the integrated transgene is replicated and passed into every embryonic cell lineage, minimizing germline mosaicism.
• nalysis:
• (One-cell-stage): Correct developmental stage.

Correct option: (1) One-cell-stage.