TN State Board 12th Zoology Question Paper 2023

Competition between species, specifically competitive exclusion, often leads to the extinction or local elimination of the weaker species if they compete for the same limited resource. Amensalism is a relationship where one is harmed and the other unaffected, Symbiosis is a close association, and Mutation is a genetic change; none are the direct primary consequence of interspecific competition.

Statins, produced by the yeast Monascus purpureus, act by competitively inhibiting the enzyme responsible for the synthesis of cholesterol. Clot busters (streptokinase) dissolve clots, Tetracycline is an antibiotic, and Cyclosporin A is an immunosuppressant.

Gastrulation is the morphogenetic process during embryonic development where the single-layered blastula is reorganized into a trilaminar (three germ layers: ectoderm, mesoderm, and endoderm) structure called the gastrula.

AUG is the universal start codon which codes for the amino acid methionine. UUU codes for phenylalanine, AUC codes for isoleucine, and UAA is a stop codon.

The ZW-ZZ system of sex determination is found in birds, some reptiles, and certain species of fish and butterflies. In this system, females are heterogametic (ZW) and males are homogametic (ZZ).