13.3 nutrients cycle

Question 1

simple nutrient cycle sequence

Answer 1

1. nutrients taken up by producers as simple inorganic molecules
2. producers incorporate the nutrients into complex organic molecule
3. when the producer is eaten the nutrients pass into the consumer
4. it then passes along the food chain where the animal is eaten by other consumers
5. when the producer and consumers die, their complex molecules are broken down by saprobiontic microorganism which release the nutrient in its simple form

Question 2

what % of the atmosphere is nitrogen

Answer 2

78%

Question 3

what form do plants take the nitrogen in

Answer 3

• nitrate ions (NO3-) in the soil
• absorbed by active transport via the roots

Question 4

how do animal gain nitrogen

Answer 4

• by eating and digesting plants

Question 5

what are the 4 main stages in the nitrogen cycle

Answer 5

• ammonification
• nitrification
• nitrogen fixation
• denitrification

Question 6

what happens during ammonification

Answer 6

• the production of ammonia forms organic nitrogen containing compounds
• saprobiontic feed on feces and dead organism material which forms ammonic on the soil releasing nitrogen to the non living component of the ecosystem

Question 7

what happens during nitrification

Answer 7

• oxidation reaction of the conversion of amino ions to nitrate ions
• uses nitrifying bacteria
  1. oxidation of amino ions to nitrate ions
  2. oxidation of nitrite ions to nitrate ions

Question 8

what is nitrogen fixation

Answer 8

• nitrogen gas is converted into nitrogen containing compounds
• carried out by 2 different nitrogen fixing bacteria

Question 9

what are the 2 different types of bacteria in nitrogen fixation

Answer 9

1. free living nitrogen bacteria- reduce gaseous nitrogen to ammonia which is then used to manufacture amino acids. nitrogen rich compounds are released from them when they decay
2. live in the nodules on the roots of the bean . obtain carbohydrates from the plant and the plant acquires amino acid from the bacteria

Question 10

what is denitrification

Answer 10

• anaerobic denitrifying bacteria convert soil nitrate into gaseous nitrogen

Question 11

outline the phosphorus cycle

Answer 11

phosphate ions are in rocks in the sea and are brought to the surface by the geological uplifting of rocks
- rock erosion dissolves phosphate ions making them available for plants to absorb
- included in their biomass which is passed into the animal
- excess phosphate excreted in waste material like guano
- decomposers break down plants and animals releasing the phosphate into the water or soil
- some phosphate remains in the bones or shells and are slow to break down
- phosphate ions are transported by streams into the ocean where they form sedimentary rocks