What you’ll learn3 learning objectivesChoose one objective for a focused lesson, or study the complete topic.19.3.1Carbon cycle• Describe the carbon cycle, limited to: photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustionSyllabus objective19.3.2Nitrogen cycle with reference to: •• Describe the nitrogen cycle with reference to: • decomposition of plant and animal protein to ammonium ions • nitrification • nitrogen fixation by lightning and bacteria • absorption of nitrate ions by plants • production of amino acids and proteins • feeding and digestion of proteins • deamination • denitrificationSyllabus objective19.3.3Roles of microorganisms• State the roles of microorganisms in the nitrogen cycle, limited to: decomposition, nitrification, nitrogen fixation and denitrification (generic names of individual bacteria, e.g. Rhizobium, are not required)Syllabus objective