This article explores why certain types of conversations are effective to develop disciplinary knowledge during video game play while others are not. In particular, we analyze conversations among students playing an educational video game that focuses on the process of viral replication. To do so, we use an emergent qualitative coding strategy. In this process, we identify three different types of conversational patterns: general, content and situated conversations. General conversations are not related to biology or other class topic. Content conversations are related to class content, but they do not involve the different sources of information available for students. Situated conversations delve into disciplinary knowledge by connecting gameplay with the information available in the educational materials. Situated conversations support the development of disciplinary knowledge by presenting the symbolic devices of the domain and bringing expert knowledge to the learning situation.