Biology:2011:CBSE:[Delhi ]:Set-III

The type of cell division that takes place in the zygote of an organism exhibiting haplontic life cycle is meiosis.

The scientific name of the microbe is Saccharomyces cerevisiae.

Dobson units (DU) is used for measuring ozone thickness.

The event that results in the gain or loss of chromosomes is aneuploidy.

Bacterial DNA can be released from the bacterial cell by treating the bacterial cells with enzymes such as lysozyme.

Cryopreservation is important in the conservation of biodiversity as gametes of threatened species can be preserved in viable and fertile condition for long periods. This technique can also be used to propagate plants using tissue culture methods. Also, seeds of commercially important plants can be kept for long periods in seed banks.

AUG is the start or initiation codon that initiates protein synthesis during translation, while UGA is the stop or termination codon that signals for the termination of protein synthesis.

The nucellar cells surrounding the embryo sac divide, protrude into the embryo sac and develop into embryos. In such species, each ovule contains many embryos. This condition of occurrence of more than one embryo in a seed is called polyembryony.

Histones are rich in basic amino acid residues such as lysine and arginine. Both lysine and arginine carry positive charges in their side chains. Thus, histone acquires positive charge from the amino acid residues with charged side chains.

CuT is most widely accepted method for spacing children. CuT increases phagocytosis of sperms within the uterus. The released Cu ions suppress sperm motility and the fertilising capacity of sperms. As a result, the sperms lose their motility.