Recycling nitrogen (OCR A-level Biology)

This lesson describes the role of decomposers and microorganisms in recycling nitrogen within ecosystems. The detailed PowerPoint and accompanying resources are part of the 1st lesson in a series of 2 lessons which have been planned to cover point 6.3.1 [c] of the OCR A-level biology specification.

The lesson begins by challenging students to recall two monomers containing nitrogen that were met in module 2, allowing them to recognise that this chemical element is a key component of nucleotides in DNA and amino acids, which are needed to synthesise proteins. Moving forwards, they will learn that despite the high % of nitrogen in the Earth’s atmosphere, it cannot be used directly by plants, and therefore plants need a supply of “fixed” nitrogen. A diagram is constantly updated and displayed as new information is introduced and this supports their understanding. The students will discover that microorganisms belonging to the Rhizobium, Azotobacter, Nitrosomonas and Nitrobacter genera are involved in nitrogen fixation, decomposition and ammonification, nitrification, and denitrification. As each of these biological actions is introduced, time is spent considering key details and understanding checks are used to allow the students to assess their progress. There are also several prior knowledge checks, where students are encouraged to make links to content met in modules 2 - 5. Answers to all questions are embedded in the PowerPoint.