This paper reports on a qualitative case study investigation of the knowledge and use of learning strategies by 16 students in a final year high school biology class to expand their conscious knowledge of learning. Students were provided with opportunities to engage in purposeful inquiry into the biological, social and ethical aspects of cancer. A constructivist approach was implemented to access prior content and procedural knowledge in various ways. Students were encouraged to develop evaluation of their learning skills independently through activities that promoted metacognition. Those students who planned and monitored their work produced essays of higher quality. The value and difficulties of promoting metacognitive approaches in this context are discussed, as well as the idea that metacognitive processes are difficult to research, because they have to be conscious in order to be identified by the learner, thereby making them accessible to the researcher.