Nitrogen Cycle A2

Question 1

define nitrogen fixation

Answer 1

nitrogen gas in air fixed by nitrogen bacteria (free living or mutualistic) converted to ammonia then ammonium ions

Question 2

define nitrification

Answer 2

nitrifying bacteria convert ammonium ions into nitrite then nitrate in an oxidation reaction

Question 3

what are nitrates used for

Answer 3

taken in by plants through roots to make proteins DNA ect.

Question 4

what is the process of ammonification

Answer 4

saprobionts break down proteins in dead plants and animals (into amino acids then ammonium)
they release enzymes (extracellular digestion) to break down proteins, and then absorb the products by diffusion

Question 5

another word for ammonification

Answer 5

saprobiotic nutrition

Question 6

what is the process of denitrification

Answer 6

anaerobic denitrifying bacteria covert nitrate to nitrogen gas

Question 7

how to increase oxygen in soil

Answer 7

ploughing

Question 8

why add oxygen to soil

Answer 8

nitrifying/saprophytic and nitrogen fixing bacteria respire aerobically

Question 9

what are mycorrhizae for

Answer 9

help a plant to take up water and inorganic ions through the roots of the plant