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.
Â©iStockphoto.com/YinYang. One of the most celebrated tropical fruits out there, mangoes are ripe for the picking in the next few months. Characterized by juicy, fibrous flesh and an oblong pit in the center, mangoes are refreshing and delicious.