B2.7: The Nitrogen Cycle

Question 1

What two major groups is nitrogen used in?

Answer 1

Proteins and DNA

Question 2

What are the three ways that nitrogen gas can get back into the soil?

Answer 2

Lightning releases energy to cause nitrogen in the air to react with oxygen to form nitrates which wash into the soil

Nitogen-fixing bacteria in the roots of plants such as peas and beans. Known an legumes. Bacteria combine nitrogen in the air with oxygen to make nitrates

Chemists are able to make ammonia industrially, using the Haber process

Question 3

How does bacteria help dead material?

Answer 3

Helps it decompose into ammonia, and convert ammonia into nitrates

Question 4

How can bacteria reverse the cycle?

Answer 4

Bacteria breaks nitrates down, and release nitrogen into the air