U1T4 - Keywords (3) Flashcards

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1
Q

Excretion

A

Removal of waste matter from an organism. (Urine)

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2
Q

Egestion

A

Removal of undigested food from an organism. (Faeces)

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3
Q

Nitrogen Fixation

A

Converts nitrogen gas into nitrogen containing compounds. Has 3 main methods (nitrogen fixing bacteria, haber process + lightning)

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4
Q

The Haber Process

A

Used to make fertilisers added to soil. Nitrogen reduced to create ammonia. Industrial method.

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5
Q

Nitrogen-Fixing Bacteria

A

Free living bacteria reduce nitrogen gas from air (air pockets in soil) into ammonia, used to synthesise amino acids for formation of proteins. Catalyse reaction with nitrogenase so it can take place at 20c unlike high temps required in Haber process. Enriches soil (farmers grow legumes + let them decay to add N2)

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6
Q

Ammonification

A

Saprobiotic bacteria/fungi feed on dead organisms/organic waste, releasing ammonia (NH4+) in water. Aided by earthworms as feed on dead organisms, breaking into small pieces (Large SA) + distributes dead material through soil.

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7
Q

Nitrification

A

Requires O2 so only occurs rapidly in well aerated soils/well oxygenated waters. 2 stages by diff nitrifying bacteria (both chemoautotrophs)

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8
Q

Chemoautotrophs

A

Derive energy for synthesis of organic molecules from oxidation reactions in nitrification.

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9
Q

Active Transport

A

Energy requiring process so proceeds best in aerobic conditions.

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10
Q

Leaching

A

When nitrates are washed out of soils due to heavy rains.

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11
Q

Denitrification

A

Denitrifying bacteria (Pseudomonas) are anaerobes + reduce nitrate (NO3-) to atmospheric nitrogen (N2) + O2 which can be used by bacteria in aerobic resp whilst N2 escapes into atmosphere. Leads to loss of nitrates from soil + can reduce soil fertility. Occurs in soils with high nitrate content but also anaerobic conditions usually caused by waterlogging.

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12
Q

Fossilisation

A

Dead organisms preserved in environments hostile to decay. (Anaerobic Conditions) Fossil fuels (coal, peat) contain locked in carbon not released as decay + decomp couldn’t occur. Carbon released by combustion.

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13
Q

Mineralisation

A

Decay + decomp by saprobiotic organisms recycling N2 in dead organisms, excreta + faeces to usable inorganic form (nitrate) 2 stages (ammonification + nitrification)

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14
Q

Nitrogenase

A

Enzyme of nitrogen-fixing bacteria that catalyses reduction of nitrogen to ammonia.

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15
Q

Putrifying (Decay) Bacteria

A

Bacteria involved in putrefaction of living matter. Recycles nitrogen from dead organisms.

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16
Q

Organic Pollution

A

Chemical pollution caused by carbon pollutants (manure/sewage)

17
Q

Indicator Species

A

Living organisms which can show pollution by being present or absent.

18
Q

Extensive Farming

A

Using more land with lower yield to produce same amount of food.

19
Q

Intensive Farming

A

Using less land, with lots of fertiliser + machinery.

20
Q

Sustainable Farming

A

Farming in ways based on understanding ecosystems.

21
Q

Biodegradable

A

Capable of being decomposed by bacteria/other living organisms + so avoiding pollution.

22
Q

Anaerobic

A

Not using much O2 to respire.