The enzyme lactase which breaks down the sugar in milk is pr

The enzyme lactase, which breaks down the sugar in milk, is produced by certain cells of the small intestine. Which of the following observations would provide the best evidence that the gene coding for lactase is being expressed in a cell?

A. The gene for lactase is present in the nucleus of the cell.

B. The cell is located in the small intestine.

C. The enzyme lactase is found in the cell.

D. Milk sugar is found in the cell.

E. Milk sugar is found in the small intestine.

Solution

C. The enzyme lactase is found in the cell

When the lactase gene is expressed, the protein synthesis occurs to produce the enzyme lactase. Thus, the presence of lactase in the cell indicates that the gene codong for lactase is expressed.