Question

A true breeding homozygous pea plant with green pods and axial flowers as dominant characters, 18 crossed with a recessive homozygous pea plant with yellow pods and terminal flowers. Work out the cross upto `F_2` generation giving the phenotypic ratios of `F_1` and `F_2` generation respectively.
(b) State the Mendelian principle which can be derived from such a cross and not from monohybird cross.

Answer 1

(a) The operon has polycistronic structural genes, i. e., three structural genes adjacent to an operator, a promoter and a regulator.
(b) Lactose IS the inducer that inactivates repressor. This allows RNA polymerase access to the promoter and initiate transcription of the structural genes or switch on the operon.


(b) From the above cross law of independent assortment can be derived which states that when two pairs of traits are combined in a hybrid, segregation of one pair of character is independent of the other pair of characters.