The article Danish researchers solve virus puzzle here describes how physicists and biologists work together to examine how viruses are produced by a cell. As far as I understand, every human cell has RNA which contains the 'recipe' on how to build proteins. The human cell also contains ribosomes that read the RNA and produce proteins. Now, the virus invades the cell, leaves its RNA in the cell. The trick: because the viral RNA resembles the human RNA, the ribosomes read the viral ribosomes and produce proteins for the construction of a virus. But the viral RNA has in contrast to the human RNA some curls, called pseudo-knots. The ribosomes have to unravel the pseudo-knot first. While doing this, they sometimes slip backwards such that the recipe is read in a different way. Now my question about the following passage in the article: I wonder about the sentence The different protein formed is the protein needed by the virus. Why can this different protein also be used to construct the protein?