3. Nutrient Cycle In Natural Ecosystems

Question 1

What is a natural ecosystem defined as being?

Answer 1

One that hasn’t been changed by humans.

Nitrogen/ phosphorous recycled through food webs.

Question 2

What 2 things do saprobiants do ?

Answer 2

They feed on remains of dead plants / animals/ waste products, breaking them done.
Secrete enzymes and digest food externally, then absorb nutrient they need.

Question 3

Because saprobiants break down deal animals and plants, what can they be considered to be ?

Answer 3

Decomposers.

Allows important chemical elements to be recycled

Question 4

What is it called when saprobiants digest food externally?

Answer 4

Extracellular digestion.

Question 5

What happens during extracellular digestion?

Answer 5

Organic molecules broken down into inorganic ions.

Question 6

What is it called when you obtain nutrients from dead organic matter and animal waste using extracellular digestion?

Answer 6

Saprobiotic nutrition

Question 7

Define mycorrhizae

Answer 7

A symbiotic relationship between a fungus and roots of the plant.

Question 8

Fungi structure

Answer 8

Long thin strands called hyphae

These connect to plant roots

Question 9

Function of hyphae

Answer 9

Greatly increase surface area of plants root helping to absorb ions from soil
Greatly increase water uptake.

Question 10

Name an ion in the soil.

Answer 10

Phosphorus

Question 11

What to fungi overall obtain?

Answer 11

Organic compound like glucose from plant.

Question 12

What is a symbiotic relationship ?

Answer 12

When 2 species live closely together and one or both species depends on one another do survival.

Question 13

Why do plants and animals need nitrogen?

Answer 13

Proteins and nucleic acids

Dna and rna

Question 14

What % of atmosphere is nitrogen?

Answer 14

78%

Question 15

Why is nitrogen in atmosphere not great?

Answer 15

Plants and animals can’t use it in this form.

So they need bacteria to convert it into nitrogen containing compounds.

Question 16

Bacteria’s role in nitrogen cycle.

Answer 16

Converts atmospheric nitrogen into nitrogen containing compounds.

Question 17

What does nitrogen cycle show ?

Answer 17

How nitrogen is converted into usable forms and then passes on between different organisms and Non living environment.
Includes food chains ( as nitrogen passed on when organisms are eaten)
4 different processes

Question 18

Name the 4 different processes in nitrogen cycle.

Answer 18

Nitrogen fixation
Ammonification.
Nitrification
Dentrification

N - AND

Question 19

What happens in nitrogen fixation ?

Answer 19

Nitrogen gas in atmosphere is turned into nitrogen containing compounds.

Question 20

What is biological nitrogen fixation carried out by ?

Answer 20

Bacteria

Which turns nitrogen into ammonia, this forms ammonium ions in solution that can be used by plants

Question 21

Where are the bacteria’s found?

Answer 21

Root nodules.
Leguminous plants.
Soul

Question 22

What type of relationship do the bacteria and plant form ?

Answer 22

Mutualistic relationship - they provide plants with nitrogen containing ions and plant provides them with carbohydrates.

Question 23

What happens in ammonification ?

Answer 23

Nitrogen compounds from dead organisms are turned into ammonia saprobiants, which go on to form ammonium ions.

Question 24

What does animal waste contain and what does this get turned into ?

Answer 24

Nitrogen compounds which turned into ammonia by saprobiants , go on to form ammonium ions.
(Ammonification)

Question 25

What happens in nitrification?

Answer 25

Ammonia ions in soil are changed into nitrogen compounds which can be used by plants - nitrates.

Question 26

What does nitrifying bacteria do ?

Answer 26

Changes ammonium ions unto nitrites.

Nitrification

Question 27

What bacteria becomes nitrified?

Answer 27

Nitrosomonas

Nitrification

Question 28

What does nitrifying bacterial called nitrobacter do ?

Answer 28

Nitrites to nitrates.

Question 29

Nitrifying nitrosomonas?

Answer 29

Ammonium ions into nitrites

Question 30

What happens in dentrification?

Answer 30

Nitrates in soil converted into nitrogen gas by dentrifying bacteria - use nitrates in soil to carry out respiration and produce nitrogen gas.
Happens under anaerobic conditions.

Question 31

Where does dentrification occur?

Answer 31

Where there’s no o2 anaerobic conditions

Water logged soil

Question 32

Name 2 other ways nitrogen into an ecosystem?

Answer 32

Lightening.

Artificial fertilisers.

Question 33

Lightening.

Answer 33

Fixes atmospheric nitrogen into nitrogen oxides.

Question 34

Artificial fertilisers.

Answer 34

Produced from atmospheric nitrogen on industrial scale in Haber process