Secondary school biology teachers’ planned topic-specific pedagogical content knowledge for teaching respiration

Topic-specific pedagogical content knowledge (TSPCK) allows teachers to transform content into forms that learners can easily understand. This study examined secondary school teachers’ planned TSPCK in respiration using 28 teachers’ content representations (CoRes). The teachers were selected from two districts of Zambia. The CoRes ( n = 28) were scored using a rubric and analysed descriptively in SPSS, while CoRe texts were analysed thematically. The mean TSPCK score indicated an overall basic TSPCK level ( M = 1.59, SD = 0.65). Teachers’ knowledge of conceptual teaching strategies ( M = 1.96, SD = 0.74), representations and analogies ( M = 1.96, SD = 0.84) received the highest scores. However, teachers’ knowledge of students’ prior knowledge—including misconceptions—( M = 1.25, SD = 1.14), what makes the topic easy or difficult to teach or learn ( M = 1.32, SD = 1.19), and curricular saliency ( M = 1.43, SD = 0.63) received the lowest scores. The qualitative findings further revealed fragmented integration of TSPCK components, with pedagogical decisions often disconnected from learners’ prior knowledge—including misconceptions—and conceptual difficulties. Furthermore, teachers mentioned typical misconceptions and learning difficulties related to respiration. The findings suggest the potential value of targeted professional development and strengthened emphasis on topic-specific PCK in teacher education. The study recommends integrating structured tools, such as CoRes, into teacher education to improve teachers’ ability to address misconceptions, identify curricular saliency, and foster the coherent integration of TSPCK components. Future research may extend to larger samples and triangulate CoRe data with classroom observation and learner data across different contexts.