Topic 5: Nutrient Cycles

Question 1

Why is nitrogen important for plants?

Answer 1

• they are used by plants to make chlorophyll or proteins
  -if they are nitrogen deficient then they cant make either so are pale and stunted

Question 2

How do phosphorous deficient plants appear?

Answer 2

• they are stunted in growth
• they tend to have purple margins around stems and veins

Question 3

What are Saprobionts?

Answer 3

• microorganisms that carry out saprobiotic nutrition and decomposition

Question 4

What kind of digestion are Saprobionts involved in?

Answer 4

Extra-cellular digestion

Question 5

How are Saprobionts, like bacteria and fungi, involved in extra-cellular digestion?

Answer 5

-they secrete digestive enzymes onto the dead material
= the large insoluble molecules are hydrolysed into smaller ones that can be absorbed

Question 6

What are the 4 stages of the Nitrogen cycle?

Answer 6

-Nitrification
-Ammonification
-Denitrification
-Nitrogen Fixation

Question 7

Why is the nitrogen cycle important?

Answer 7

Producers use nitrogen to synthesise amino acids, proteins, nucleic acids, ATP and other nitrogen containing compounds like chorophyll
Consumers obtain the nitrogen they need from the digestion of organic material

Question 8

How much of the air does nitrogen make up?

Answer 8

80%
It is an unreactive gas

Question 9

Name 2 sources of nitrogen for producers and where they are found

Answer 9

-nitrate ions
- ammonium ions
-from soil or water