Nutrient Cycles

Question 1

What is an amino acid?

Answer 1

Monomer unit joined together to form a polypeptide

Question 2

What are nucleotides?

Answer 2

Monomer unit joined together to form DNA or RNA

Question 3

What are the stages of the nitrogen cycle?

Answer 3

Nitrogen fixation, nitrification, decay and ammonification, dentrification

Question 4

What is nitrogen fixation?

Answer 4

Conversion of nitrogen gas into ammonium ions by free living nitrogen fixing bacteria found in the soil

Question 5

What is nitrification?

Answer 5

Ammonium ions are converted to nitrates (NO2) then nitrates (NO3-) by nitrifying bacteria

Question 6

What is decay and ammonification?

Answer 6

Breakdown of proteins found in decomposing material by saprobiont bacteria into amino acids. Amino acids are then converted to ammonium ions by ammonifying bacteria.

Question 7

What is dentrification?

Answer 7

Conversion of nitrates (NO3-) into nitrigen gas which is released into air when dentrifying bacteria respire anaerobically.

Question 8

How does lightening cause nitrogen fixation?

Answer 8

Lighteneing adds to the soil. Nitrogen and oxygen combine to make nitrogen oxides. Lightening breaks the triple bonds in nitrogen allowing oxygen to combine with it. Nitrogen oxides formed dissolve in rain forming nitrates.

Question 9

How does bacteria cause nitrogen fixation?

Answer 9

Mutalistic bacteria are found in roots of leguminous plants. This is a mutalistic relationship where by bacteria provides the plant with nitrogen from air in return for carbohydrates.

Question 10

What else causes nitrogen fixation?

Answer 10

Use if articificial fertilisers?

Question 11

What is the nitrogen cycle?

Answer 11

Helps bring in the inert nitrogen from the air into the biochemical process in plants and then to animals. Plants need nitrogen to synthesise chlorophyll.

Question 12

Why does the nitrogen cycle occur?

Answer 12

Atmospheric nitrogen cannot be used by most organisms and must be converted into a usable form

Question 13

What are phospholipids used for?

Answer 13

Used to make cell membranes

Question 14

What is the role of ATP?

Answer 14

It is hydrolysed to relsease energy

Question 15

What is the phosphorus cycle?

Answer 15

Process by which phosphorus moves through the lithosphere, hydroshpere and biosphere

Question 16

Why is the phosphorus cycle needed?

Answer 16

Phosphorus is essential for plant and animal growth as well as health of microbes inhabiting soil.

Question 17

What are key stages in the phosphorus cycle?

Answer 17

Weathering, plant decay, feeding and digestion, waste products, decomposition, animal decay

Question 18

How does weathering produce phosphorus?

Answer 18

PO4(3-) ions are in sedimentry rocks, weathering causes erosion of these rocks so phosphorus ions dissolve in rain water and go to bodies of water.

Question 19

How does decomposition contribute to phosphorus cycle?

Answer 19

Other phosphorus ions from bones, shells, waste products and guano form sea birds decompose slowly and dissolve in water sorces, ending up in bodies of water

Question 20

How does the death of animals contirbute to the phosphorus cycle?

Answer 20

Phosphorus ions are transferred to animals when they eat plants, when animals die, decomposers break down the animal body releasing phosphorus ions, this can end up in a body of water. Waste products of these animals can also decompose.

Question 21

How does feeding and digestion contirbute to the phosphorus cycle?

Answer 21

Phosphorus ions are absorbed via plant roots via active transport, when animals eat these plants phosphorus ions are transferred to them.

Question 22

How does soil and bodies of water contribute the phosphorus cycle?

Answer 22

Phosphorus ions from weathering, decomposing and decay end up in soil and bodies of water through these ions dissolving in rain, plants then absorb these ions through thier roots.

Question 23

What is mycorrhizae?

Answer 23

Mutalistic associations between fungi and plant roots.

Question 24

What is the function of fungi in a plant?

Answer 24

It is an extension of the root system.

Question 25

What is the advantage of fungi on plants?

Answer 25

Increases the surface area for absorption of water and mineral ions e.g nitrate/phosphate, they jold water in the nieghborhood of the roots to protect the plant against drought.

Question 26

What are fertilisers?

Answer 26

Chemical compounds applied to soil for plants to absorb to increase plant growth/yeild.

Question 27

What are natural fertilisers?

Answer 27

Compounds of organic matter

Question 28

What are artificial fertilisers?

Answer 28

Composed mineral ions mainly NPR. Very soluable and normally these fertilisers are made by mining rocks

Question 29

What are the three major consequences of fertiliser overuse?

Answer 29

Leaching, reduced species diversity, eutrophication.

Question 30

What is leaching?

Answer 30

Leaching is a consequence of fertiliser overuse, soluable ions dissolve into rain water, water carries soluable ions to rivers and bodies of water, this has a harmful effect on humans eg high nitrate can prevent 02 carriage by heamoglobin, leaching also leads to eutrophication.

Question 31

How does reduced species diversity from fertilisers occur?

Answer 31

Soils rich in nitrates favour the growth of grasses and other rapidly growing species, these outcompete many other species, so species diversity is reduced.

Question 32

What is eutrophication?

Answer 32

Build up of mineral ions to a body of water. Water soluable ions causes algal bloom, this nlocks out light so light becomes a limiting factor, aquatic plants die increasing dead organic matter in water. Saprobiontic bacteria use the dead organic matter as a food source then oxygen becomes a limiting factor. Aerobic organisms begin to die. Anearobic bacteria further decomposes dead organic matter releasing hydrogen and toxic wastes which makes the water putrid

Question 33

What is the carbon cycle useful for?

Answer 33

Tranfers carbon to air, decomposers, fossil fuels, plants, animals