phosphorus cycle and fertilisers

Question 1

1. What molecules contain phosphorous?

Answer 1

ATP, phospholipids and nucleic acids.

Question 2

2. Where does phosphorus mostly exist?

Answer 2

Phosphate ions in the form of sedimentary rock deposits.

Question 3

3. How are phosphates in rocks released?

Answer 3

Weathering and erosion, and the use of fertilisers (rocks reacted with sulphuric acid to produce phosphate fertiliser).

Question 4

4. How are phosphates absorbed by plants?

Answer 4

They need to be dissolved in water then absorbed by the root hair cells.

Question 5

5. What is guano?

Answer 5

The accumulated excrement of some sea birds and cave dwelling bats that has high levels of phosphate ions

Question 6

6. How are phosphate ions released from dead organisms?

Answer 6

Saprobionts decompose them, releasing phosphate ions. Saprobionts release extracellular enzymes to hydrolyse large molecules into small inorganic ions.

Question 7

7. Why do farmers need to add fertilisers?

Answer 7

When crops are harvested, plants are removed from the soil so do not decay and replace mineral ions in the soil.

Question 8

8. How do fertilisers increase yields?

Answer 8

They enable to plants to make more biological molecules (biomass) and therefore grow more.

Question 9

9. What is leaching?

Answer 9

Rainwater dissolves any soluble nutrients and carries them away from the soil.

Question 10

Rainwater dissolves any soluble nutrients and carries them away from the soil.

Answer 10

Eutrophication