4cd- cycles + human inf

Question 1

CARBON CYCLE

Answer 1

1. CO2 USED FOR PHOTOSYNTHEISS
2. ENERGY PASSES ALONG FOOD CHAIN
3. AEROBIC RESP RELEASES INTO AIR
4. DECOMP, DEAD CELLS AND CO2 RELEASED INTO SOIL
5. FOSSILISATION, STORED AS FOSSIL FUIELS
6. COMBUSTION OF FFS RELEASES CO2 BACK INTO AIR

Question 2

WHY IS NITROGEN CYCLE A THING WHEN IT IS ABUNDANT IN AIR?

Answer 2

• n2 unreactive, unable to take straight from air
• only NH3 & NO3

Question 3

NITROGEN FIXING BACTERIA

Answer 3

N2 –> NO3 (plant root nodules)
N2 –> NO3 (Lightning gives enough energy to react)

Question 4

DECOMPOSING BACTERIA

Answer 4

urea/proteins –> into soil –> NH3

Question 5

NITRIFYING BACTERIA

Answer 5

NH3 –> NO2 –> NO3

Question 6

DENITRIFYING BACTERIA

Answer 6

NO3 —> N2

Question 7

NITROGEN CYCLE:

Answer 7

1. N2 –> NO3

using a) root hair nodules and nitrogen fixing bacteria OR b) lightning gives enough energy to react)

2. N2 –> NH3 –> NO2 –> NO3

using a) decomposing bacteria to convert urea by animal into NH3 and THEN b) nitrifying bacteria to further convert into NO3

3. NO3 –> NO2

using denitrifying bacteria to convert back to N2 into atmosphere

Question 8

greenhouse effect

Answer 8

SUN = SHORT WAVE RADIATION

earth –> reflects as long wave (some)
earth –> absorbs and trapped by GHG in atmosphere

BUTTT excess of GHG trapps too much heat into atmospher = GLOBAL WARMING

Question 9

GHGS: (5)

Answer 9

1. H2O
2. CO2
3. NO2/NO3
4. CH4
5. CFCS

Question 10

CO2 AS A GHG

Answer 10

• burning FFS
• houses, veichles, powerstations, manufacturing
• deforestation (carbon cycle ref.)

Question 11

NO2/3 AS A GHG

Answer 11

• car fumes (But now catalytic converters)
• fertilisers (denitrying bacteria –> more n2 into earth and reacts w o2)

Question 12

CH4 AS A GHG

Answer 12

• more cattle from intensive farming and need to feed + product of digestion
• decay of landfills
• rise production, bacteria produce

Question 13

CFCS AS A GHG

Answer 13

• aerosols and fridges
• destroyed ozone layer
• more uv rays in, cell mutation.. cancer

Question 14

effects of GLOBAL WARMING

Answer 14

• ice caps melt
• sea level rise
• loss of habitat
• desertification/droughts
• extinctions –> disrupted food chains/migration
• change in ecosystems
• spread of disease
• extreme changes in weather patterns and climate change

Question 15

CO POISINING

Answer 15

• incomplete combustion of fuel
• binds w haemoglobin
• prevents o2 from being carried in blood

Question 16

ACID RAIN

Answer 16

• caused by sulfates and nitrates
• fuel inpurities, combusted
• acidic gases dissolve in rain water, producing acidic solutions

effects:
- acidifies lakes
- kills animals and plants
- releases toxic subs from soil
- stops minerals from being absorbed
-destroys limestone

Question 17

DEFORESTATION

Answer 17

1. less evotranspiration: local climate is drier, humidity decreases
2. leeching: exposed soil dries up, rainwater runs off and takes minerals w it = infertile soil
3. soil erosion: rain causes soil to get washed away, no tree roots hold it in place and less interception
4. less o2, more co2

Question 18

EUTROPHICATION

Answer 18

causes: untreated sewage, pesticides, fertiliser nitrates

process:

LEECHING
excess nitrates in ponds
growth of algae (algal bloom)
blocks light for bottom plants
plants die due to lack of light (no ps)
plants decay and decompose
bacteria uses up o2 in water
anoxic water levels
other animals die
no respiration