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17 Cards in this Set

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This graph shows part of the nutrient cycle. Which one of the processes involved nitrification? [1]

This graph shows part of the nutrient cycle. Which one of the processes involved nitrification? [1]

-R

This figure includes one process by which microorganisms add ammonium ions to soil. Describe another process carried out by microorganisms which adds ammonium ions to soil [2]

This figure includes one process by which microorganisms add ammonium ions to soil. Describe another process carried out by microorganisms which adds ammonium ions to soil [2]

-Proteins broken down




-by saprophytes

Denitrification requires anaerobic conditions. Ploughing aerates the soil. Explain how ploughing would affect the fertility of the soil [2]

-Fertility increased as more nitrated accumulates




-No denitrification because soil not anaerobic

One farming practice used to maintain high crop yields is called crop rotation. This involves growing a different crop each year in the same field. Suggest two ways in which crop rotation may lead to high crop yields [2]

-Growing plants with nitrogen fixing bacteria




-different crops use different minerals from the soil so soil can regenerate

Climate change has resulted in an increase in the concentration of salt in the soil water of some parts of the world. Suggest how climate change could result in an increase in soil salinity [2]

-Higher global temperature




-Increase in evaporation from soil, leaving salt behind

Explain why crops don't grow when soil salinity is above 2% [2]

-Soil has reduced water potential




-so water leaves roots by osmosis

Use your knowledge of photosynthesis and respiration to describe and explain how the concentration of carbon dioxide in the air changes over a period of 24 hours, and at different heights above ground [5]

-High concentration of CO2 caused by more respiration than photosynthesis at night




-No photosynthesis at night because no light




-In light, net uptake of CO2 reduced CO2 concentration




-Decrease in concentration of CO2 with height




-Because less photosynthesis at ground level

Give a biological molecule that contains nitrogen [1]

Amino acid, protein, enzyme, urea, nucleic acid, chlorophyll, DNA, RNA, ATP

Give a biological molecule that contains Phosphorus [1]

DNA, RNA, nucleic acid, ATP, ADP, etc

Describe the role of microorganisms in producing nitrates from the remains of dead organisms [3]

-Saprophytes break down remains and DNA into ammonia




-Ammonia ions converted into nitrite and nitrate




-By nitrifying bacteria

Upwelling is a process where water moves from deeper parts of the sea to the surface. This water contains a lot of nutrients from the remains of dead organisms. Nitrates and phosphates are two of these nutrients. They provide a source of nitrogen and phosphate for cells. Upwelling often results in high primary productivity in coastal waters. Explain why some of the most productive fishing area are found in coastal waters [2]

-Nitrates absorbed by producers




-More producers mean more consumers so fish thrive

Explain how human activities have contributed to global warming [4]

-CO2 is a greenhouse gas




-Deforestation removes trees so less CO2 removed by photosynthesis




-Combustion releases CO2




-Methane is a greenhouse gas




-Cattle produce methane

Explain how the intensive rearing of domestic livestock increases net productivity [4]

-slaughtered when young so more energy transferred to biomass




-Fed on concentrated food source so more food assimilated for biomass




-Movement restricted so less respiratory loss




-Kept warm so less energy used to maintain temperature




-Genetically selected for high productivity

Name processes P and Q [2]

Name processes P and Q [2]

-P = Nitrification




-Q = Denitrification

Leguminous crop plants have nitrogen-fixing bacteria in nodules on their roots. On soils with a low concentration of nitrate ions, leguminous crops often grow better than other types of crop. Explain why [2]

-Nitrogen fixing bacteria convert nitrogen to ammonia




-so plants can produce more protein

Applying very high concentrations of fertiliser to the soil can reduce plant growth. Use your knowledge of water potential to explain why. [2]

-Reduces water potential of soil




-so water leaves roots by osmosis

Describe the reasons for the low efficiency of energy transfer through ecosystems [5]

-Some light not correct wavelength so reflected off leaves




-Some light misses leaves




-Heat loss




-Respiratory loss




-Energy loss through faeces