<p> The Nitrogen Cycle</p><p>Instructions: Go to http://www.vtaide.com/png/nitrogenCycle.htm - Complete the diagram below by filling in the blanks. - Move your cursor over each component of the nitrogen cycle to learn more about it and then answer the questions below. </p><p>Questions on the Nitrogen Cycle</p><p>1. Why is nitrogen so important to all life? (refer also p. 25-27 in text) 2. Almost 79% of the atmosphere is nitrogen [N2(g)], but neither plants or animals can use this form of nitrogen directly. For use by organisms it must be supplied in the form of - the nitrate ion NO3 . Therefore, it must be “fixed” first. This is done through the - process of Nitrogen fixation (N2  NO3 ). List the three different ways atmospheric nitrogen is fixed.</p><p>3. Nitrogen fixation in soil: What type of relationship exists between Nitrogen-fixing bacteria and the plant it lives on? </p><p>Nodules</p><p>Explain how this relationship works. </p><p>What are nodules? </p><p>4. a) List the 3 decomposers involved in the nitrogen cycle. </p><p> b) What is the difference between aerobic and anaerobic bacteria? </p><p> c) What is the role of decomposers? </p><p> d) What is this process called? + - 5. a) What type of bacteria converts ammonium (NH4 ) to nitrates (NO3 )? </p><p> b) Why are nitrates so important? </p><p>6. What does denitrifying bacteria do? </p><p>7. What is assimilation? </p><p>8. a) How do animals get nitrogen?</p><p> b) How do you think animals return nitrogen to the soil? </p><p>9. How do plants return nitrogen to the soil? </p><p>10. Why do farmers use fertilizers? </p>