How to Write an Essay

Here’s an example of how to write an essay. Our topic is nitrogen fixing bacteria.

Outline:

• Introduction: Define nitrogen fixing bacteria, explain their importance for the nitrogen cycle and agriculture, and state the main purpose of the essay.
• Body: Discuss the different types of nitrogen fixing bacteria, their characteristics, and their interactions with plants and other organisms.
  • Free-living bacteria: Describe examples such as Azotobacter, Beijerinckia, and Clostridium, and how they fix nitrogen in the soil or aquatic systems.
  • Symbiotic bacteria: Explain how bacteria such as Rhizobium, Frankia, and Azospirillum form mutualistic relationships with legumes, actinorhizal plants, and cereal grasses, and how they form root nodules and exchange nutrients with the host plants.
  • Other nutrient mobilizing bacteria: Mention how some bacteria can help plants obtain other nutrients such as phosphorus, calcium, magnesium, sulfur, and micronutrients, by solubilizing, oxidizing, or chelating them.
  • Plant growth promoting rhizobacteria (PGPR): Highlight how some bacteria can enhance plant growth by increasing iron nutrition, reducing root pathogens, and producing plant hormones.
  • Decomposers: Emphasize the role of microorganisms such as Trichoderma fungi in breaking down dead organic matter and returning nutrients to the soil.
• Conclusion: Summarize the main points of the essay, restate the main purpose, and provide some implications or recommendations for further research or practice.

Sample introduction:

Nitrogen fixing bacteria are microorganisms that can convert atmospheric nitrogen into ammonia or other nitrogenous compounds that can be used by plants. Nitrogen fixing bacteria play a vital role in the nitrogen cycle, which is the process of transforming nitrogen among different forms in the biosphere. Nitrogen fixing bacteria are also essential for agriculture, as they can increase the soil fertility and the plant productivity, without the need for synthetic fertilizers. The purpose of this essay is to explore the diversity and the functions of nitrogen fixing bacteria, and how they interact with plants and other organisms in different ecosystems.