Due to the nature of biological based inventions, it may not always be sufficient for the applicant to list the steps necessary to create the product. In these cases, the PTO will request that a “deposit” is made so that members of the public desiring to use the particular product will have access to it. An example of this would be a specific tissue culture cell type.

In other cases, when the invention seeking to be patented involves a nucleotide or amino acid sequence, that sequence must be listed in the patent.

You may see a couple of questions related to biotechnology patents on the patent bar exam.