In the absence of lactose, the repressor protein encoded by the I gene binds to the lac operator and prevents transcription. Binding of allolactose to the repressor causes it to leave the operator. This enables RNA polymerase to transcribe the three genes of the operon.
A tough-skinned tropical fruit, the mango features a sweet, orange- to red-color flesh inside when ripe. Kensington pride, Kent, Palmer and sensation are only a few of the many varieties of mango available through groceries and markets.
Shell color is not necessarily a sign of maturity or ripeness. A pineapple can be ripe when it is practically all green outside. The plantation calls it âgreen-shell ripe.â Shell color of ripe fruit are divided into seven groups or levels ranging from No. 0, all green, to No. 6, all yellow. A pineapple will not ripen any further â get any sweeter â after picking.