Q.(a) Illustrate the mechanism by which Dolly, the sheep was born. OR

(a) Dolly resulted from somatic cell nuclear transfer cloning. (b) AIDS presents with characteristic constitutional symptoms and opportunistic infections as defined by WHO.

(a) To create Dolly, scientists took a mammary (udder) cell from an adult Finn Dorset ewe and removed its nucleus, then transferred that nucleus into an egg cell from a different ewe whose own nucleus had been removed (enucleated); an electric pulse fused the somatic nucleus with the egg cytoplasm and triggered the reconstructed cell to begin dividing as an embryo, which was then implanted into the uterus of a surrogate mother sheep, ultimately developing into Dolly — genetically identical to the nucleus-donor ewe. This process, somatic cell nuclear transfer (SCNT), was the first successful cloning of a mammal from an adult somatic cell. (b) WHO's clinical case definition for AIDS (advanced HIV disease) includes a set of major and minor signs: major symptoms are significant unintentional weight loss (over 10% of body weight), chronic diarrhoea lasting more than a month, and prolonged fever for over a month; minor symptoms include persistent cough, generalised itchy skin conditions, recurrent shingles (herpes zoster), oral thrush (candidiasis), chronic progressive or disseminated herpes simplex infection, and generalised swollen lymph nodes; the appearance of …