Jacob, Monod, and Pardee constructed a mutant strain of E. coli that carried a laci-gene mutation (encodes the lac repressor). Which of the following is true of this mutant strain?
1) It will produce a functional lac repressor
2) It will not produce a functional lac repressor
3) It will produce a functional lac repressor only in the presence of lactose
4) It will produce a non-functional lac repressor only in the presence of lactose