A2 quiz

Question 1

explain the water cycle

Answer 1

connects ecosystems
1) liquid water in lakes/ponds is turned into a gas through evaporation
2) water vapout in atmosphere condenses in clouds
3) Liquid water returns to the ground through precipation
4) Water re enters lakes/ponds/oceans through run offs

Question 2

what makes water the universal solvent

Answer 2

water molecules are polar(different charges at each end) this results in a week attraction between molecules known as a hydrogen bond
this enables water to dissolve wide variety of substances

Question 3

what biogeochemical cycling

Answer 3

porcess of transporting dissolved materials
movement of nutrients between biotic and abiotic factors

Question 4

what allows water to remain liquid and how does it change states

Answer 4

hydrogen bonding allows water to remain liquid state across a lagre temp range
large amounts of energy are required to change state (high boiling point and low melting point point

Question 5

explain water densisty

Answer 5

more dense as a liquid then a solid
most dense at 4 degrees celcius
water warms or cools gets less dense
when water cools hydrogen bonds losen causing solid water to have a lower densisty causing ice to float

Question 6

what is cohesion in water

Answer 6

water molecules are polar so they are attracted to one other, this causes cohesion which is responsible for surface tension

Question 7

what is adhesion in water

Answer 7

water molcules are attracted to molecules of other substances, porvides upward force counteracting the pull of gravity

Question 8

what are some examples of carbon sinks and how is carbon relased from them

Answer 8

trees, fossil fuels deposists, oceans and lime stone rocks
carbon is realsed from reservoirs both quickly (forest fires) and slowing weathering)

Question 8

What is the green house effect in water

Answer 8

when water is scarce plants respond by closing their stoma, this reduces transpiration meaning it cannot take in CO2 which slows photosynthesis
due to the greenhouse effect metabolic activites (cell resp and photo syntheis) slow and less CO2 is taken from the air

Question 8

what is slow cycling in the carbon cycle

Answer 8

carbon accumulates and is stored in various reservoirs (carbon sinks) for long periods of time where is it unavaiable to organisms until realsed

Question 8

what is weathering

Answer 8

wearing down or breaking of rocks

Question 9

what are some human impacts on the carbon cycle (5)

Answer 9

hydrocarbon combustion (CO2 in atmosphere)
deforestation (removing carbon sinks)
human caused forest fires
agriculutre
acification of oceans (co2 in h20 aka carbonic acid

Question 10

where is the carbon

Answer 10

in abotic enviroenments some carbon is in the form of CO2 is held in the atmosphere however majoirty dissolved in worlds oceans
although primary source for use by the biotic enviroenment is the atmosphere

Question 11

what is carbon fixtation

Answer 11

carbon is captured from the atmpsphere through photosyntheis and is realsed through cell resp

Question 12

how does carbon get realsed back into the atmpsphere

Answer 12

• remaining carbon in living organisms is returned to the atmosphere or to the water cycle when waste decays
• if this proccess is delayed and the bdoies become burried under large rocks it is possible to create fossil fuels

Question 13

how is carbon found in aquatic ecosystems

Answer 13

carbon is incorporated into carbonate compounds which is used to form shells
this carbon can also be trapped in the form of sedimentary rocks
carbon trapped in carbonate rocks like limestones can be realesed by heat produced by volcanic activty, this heat breaks down the rock relasing CO2 in the atompshere

Question 14

What are the proccess invovled in the carbon cycle (8)

Answer 14

• photosynthesis/ chemosyntheis aka carbon fixtation
  celluar resp
  death and decay or organisims
  fossilaztion
  burning fossil fuels
  formation of carbonate compounds
  sedimentation
  volcanic heating of carbonate rocks

Question 15

what is sedimentation

Answer 15

organic or inorganic carbon will settle to the bottom of the ocean or freshwater system creating sediemnts rich in carbon

Question 16

why does nitrogen cycle and why is it important

Answer 16

most organisms cannot use atmospheric nitorgen (N2)
makes up 78% of earths atmosphere and is essiental compenet in our DNA

Question 17

Explain the nitrogen cycle

Answer 17

• Ammonia (NH3 or NH4 is coverted into
• nitrites (NO2) then
• nitrates (NO3)
  this can then be used by plants which are eaten by animals

Question 18

what is denitrifcation

Answer 18

excess nitrates in the soil are converted back into atmosphereic nitrogen by a different set of bacteria
these bacteria are…
- anaerboic (O2 intolerant)
- live in the soil
-remove nitrates and nitrites and covert them into nitgrogen gas and nitruous oxide which returns to the atmosphere
this proccess will increase in rate if the soil is acidic or waste logged

Question 19

what is nitorogen fixtation

Answer 19

invloves converting gaseous nitrogen into a form available to the biotic enviornemnet (ammounim or nitrates)

Question 20

how does nitorgen fixtation happen

Answer 20

Lighting- causes reaction betwene nitrogen gas and oxygen in the air result is the formation of NO3 - ions which combine with water to enter the soil
Nitrogen fixing bacteria- bacteria fix nitroegn gas from the air prouding ammonia NH3 which becomes ammonium NH4
Nitrifying bacteria- convert NH4 into NO2 then NO3
these bacteria are found in the soil and root nodules on legumes, provides plants woth more then enough nitrogen

Question 21

explain the relashionship between nitrogen fixing bacteria and plants

Answer 21

they are often associated with the roots of legume (bean plants) such as clover
bacteria convert nitorgen into ammounium for the plants and in returen plants prodvide bacteria with sugars

Question 22

Atmospheric nitrogen fixtation:

Answer 22

lighting converts N2 into N03

Question 23

nitrogen fixing bacteria:

Answer 23

convert N2 into NH4

Question 24

nitrfying bacteria:

Answer 24

convert ammonium ions into nitrates NH4 into NO3

Question 25

what is the formula for nitrites

Answer 25

NO2

Question 26

formula for nitrates

Answer 26

NO3

Question 27

why is phosphorus important and where is it found

Answer 27

essential nutrient (found in bones and teeth) but it is found in limmited quanities
does not cycle through the atmosphere but instead found in soil and water, often added ti crops as a fertilizer

Question 28

how can aniamls and plants obtain phosphorus

Answer 28

animals- eating milk grains and meats
plants- can only use in form of phosphates which disolve in H2O

Question 29

where is phosporus long/short cycle

Answer 29

Long cycle- invloving rocks and earth’s crust
short cycle- invloving living organisms

Question 30

what are some proccess invloved in the phosporus cycle (8)

Answer 30

• geological uplift
  -errosion/weathering
  -decomposition
  -ingestion
  -aboorbiton
  -leacing
  -sedimentation
  -run off

Question 31

human impacts on the amount of phosporus

Answer 31

• detergents (used to conatain phosphates)
• agriculture (fertilizers)
• golf courses
• excess nutroents in lakes/ rivers - eutrophication aka algeal bloom

Question 32

what are stromata lights

Answer 32

produced by cyanobacteria, are the houses for these bacteria
cyano- first form of photosyntheies realses oxygen back into the atmosphere

Question 33

human impacts on nirtogen cycle

Answer 33

• burning of fossil fuels
• fertilizers
  -run off
  -leacing
• eutrophication

Question 34

list some rapid and slow cycling parts of the carbon cycle

Answer 34

vegetation , forest fires, fossil fuels, decompistion
slow: rocks, ocean and atmosphere