Beta () diversity refers to diversity
within a community
between communities
between two eco zones
within a population
Which one of the following antibiotics kills bacterial cells by inhibiting the polymerisation of peptidoglycan?
Aminoglycosides
Fluoroquinolones
Quinines
Penicillins
Indicate the correct sequence during spermatogenesis.
Spermatozoa spermatogonia spermatid spermatocyte
Spermatogonia spermatocyte spermatid spermatozoa
Spermatid spermatocyte spermatozoa spermatogonia
Spermatocyte spermatozoa spermatid spermatogonia
Egg in female gametophyte is accompanied by
antipodal cells
synergids
definitive nucleus
tube nucleus
B.
synergids
Synergids are two specialised cells that lie adjacent to the egg cell in the female gametophyte of angiosperms and play an essential role in pollen tube guidance and
function. These are responsible for cessation of pollen tube growth and release of the sperm cells.
Antipodals are nutritive in function and they nourishes the embryo sac. Substances developed by these cells helps in growth and development of endosperm.
Definitive nucleus is the diploid nucleus found in the centre of the embryo.
Tube nucleus is the one of the two nuclei formed by mitotic division of a microspore during the formation of a pollen grain.
Which one of the following organisms is not used as a biocontrol agent?
Bacillus sphaericus
Trichoderma viride
Bacillus thuringiensis
Bacillus subtilis
Which one of the following statements is relevant to sex linked characters?
They always follow criss-cross inheritance
They do not follow criss-cross inheritance
They are mostly present on Y-chromosome
They are only present on X-chromosome
Which one of the following insecticides is of plant origin?
Ecdysone
Rotenone
Parathion
Malathion
Archaeopteryx is a connecting link between
pisces and amphibians
amphibians and reptiles
reptiles and birds
birds and mammals