Nitrogen cycle

Start with a picture of the cycle

A Nitrogen Cycle mind map introduces nitrogen in the atmosphere and explains why plants and animals need it. It also shows how plants get nitrogen from the soil and animals get it by eating plants. Start there for an overview, then look at the Nitrogen Cycle mind map that includes ammonia, ammonium and nitrogen-fixing bacteria.

Reading a map from one part to the next can help you follow the connections rather than treating each term as a separate fact. Keep track of the stages and organisms mentioned as you go.

Practice the terms with flashcards

OCR A2 Biology: The Nitrogen Cycle asks why plants and animals need nitrogen and includes questions on fixation, ammonification, nitrification and denitrification. The Nitrogen cycle flash cards deck also asks about these processes, including the roles of free-living and mutualistic bacteria.

After reading a map, use a deck to recall what each term means. Then return to the map and locate the processes you have practiced. The Nitrogen Cycle flashcard deck provides another set of questions about nitrogen and the production of nitrates.

Use a quiz alongside a map

The quiz on nitrogen cycle bacteria asks about nitrifying, denitrifying and nitrogen-fixing bacteria. It also includes questions about conversions involving ammonia, nitrates and nitrogen in the atmosphere. Use it after the maps and flashcards to check how well you can distinguish the bacteria and their roles.

For any question you want to explore again, return to the relevant part of a mind map or flashcard deck. The quiz titled The Nitrogen Cycle offers another option for practice.

Explore the unit

Nitrogen cycle is a section of Biogeochemical Cycles in Biology and natural sciences. The Nutrient cycles mind map places nitrogen alongside carbon and sulphur and includes bacteria and plant growth. It offers a way to see the nitrogen material in a wider context within the unit.

Choose a resource and work through the cycle at your own pace.