Researchers use a variety of techniques to learn

more about the function of a specific gene in an

organism. In one type of experiment, called a

loss-of-function experiment, the gene being

investigated is eliminated. In a gain-of-function

experiment, extra copies of the gene being

investigated are inserted. The cell process most

directly affected in both experiments is

(1) protein synthesis

(2) waste disposal

(3) transport of materials

(4) breakdown of nutrients