Most academic science educators encourage teachers to provide their students with access to more authentic science activities. What can and do teachers say to increase students' interests in participating in opportunities to do real science? What are the discursive "resources" they draw on to introduce authentic science to students? The purpose of this ethnographic and discourse-analytic study is to investigate the ways in which the activities of scientists are discursively presented to high school students in a biology/career preparation course. Data sources were collected by means of observation, field notes, interviews, and videotaped lessons in an eleventh-grade biology/career preparation course. Drawing on discourse analysis, we investigate the discursive resources--or, more specifically and technically, the "interpretative repertoires"--teachers used to explain and promote opportunities to engage students in real science activities. Our analysis identifies and characterizes six types of interpretative repertoires: specialized, a-stereotypical, relevant, empirical, emotive, and rare-opportunity. To better understand the "big picture" of how these discursive resources are drawn on in the classroom, we also report on the frequencies of the repertoires in the discourse and the ways in which repertoires changed in the course of teacher-student interactions. The findings of this case study offer teachers and researchers a better understanding of how specific forms of discourse--i.e., the repertoires--can serve as resources to enhance teacher-introduction of authentic science to students and provide students a bridge between school and authentic science.