AQA A Level Environmental Science
Biogeochemical Cycles
Exam Practice Test
the carbon cycle - Answer>> - naturally in a state of dynamic
equilibrium with processes cancelling each other out
- little or no overall charge in the amount of carbon in each
amount of carbon
carbon cycle processes: photosynthesis - Answer>> - captures
light energy using chlorophyll
- converts low energy substances such as carbon dioxide and
water into high energy carbohydrates
- carbohydrates can be converted into proteins, lipids, amino
acids
carbon cycle processes: respiration - Answer>> - releases the
energy that was captured during photosynthesis
- energy used to drive metabolic processes
- aerobic respiration returns carbon into the atmosphere as
carbon dioxide
- aerobic respiration breaks down organic compounds more
completely
- release more energy than anaerobic respiration
carbon cycle processes: food webs - Answer>> - plants eaten
by herbivores
- herbivores are eaten by carnivores
carbon cycle processes: fossilisation - Answer>> - incomplete
decomposition of dead organic matter under anaerobic conditions
can produce substances that form substances that have a high
carbon store
, carbon cycle processes: combustion - Answer>> - burning
organic material to release carbon dioxide
carbon cycle: human impacts: changes to photosynthesis -
Answer>> - deforestation reduces the movement of carbon
from the atmosphere into biomass
- afforestation increases the movement of carbon from the
atmosphere into the biomass
- marine pollution with toxic materials can reduce phytoplankton
populations which then reduces the absorption of dissolved
carbon dioxide
- carbon dioxide in the atmosphere would have dissolved in the
sea to maintain the balance between CO2 in the atmosphere and
the sea
- more toxic pollution that kills the phytoplankton leads to an
increase in atmospheric carbon dioxide levels
- algae that live on the underside of ice, some of the carbon
dioxide they absorb sinks to the seabed in the faeces of krill that
eat the algae
- if climate change reduces the sea ice then less CO2 may be
removed from the sea
carbon cycle: human impacts: changes in aerobic respiration -
Answer>> - carbon in DOM is gradually released as CO2 by
aerobic respiration of soil organisms--> bacteria and fungi
- ploughing increases the oxygen supply to decomposers so
aerobic decomposition takes place more rapidly
- the amount of carbon in the soil of DOM is reduced and amount
in atmosphere increased
carbon cycle: human impacts: changes in anaerobic respiration -
Answer>> - anaerobic soil organisms release methane gas
Biogeochemical Cycles
Exam Practice Test
the carbon cycle - Answer>> - naturally in a state of dynamic
equilibrium with processes cancelling each other out
- little or no overall charge in the amount of carbon in each
amount of carbon
carbon cycle processes: photosynthesis - Answer>> - captures
light energy using chlorophyll
- converts low energy substances such as carbon dioxide and
water into high energy carbohydrates
- carbohydrates can be converted into proteins, lipids, amino
acids
carbon cycle processes: respiration - Answer>> - releases the
energy that was captured during photosynthesis
- energy used to drive metabolic processes
- aerobic respiration returns carbon into the atmosphere as
carbon dioxide
- aerobic respiration breaks down organic compounds more
completely
- release more energy than anaerobic respiration
carbon cycle processes: food webs - Answer>> - plants eaten
by herbivores
- herbivores are eaten by carnivores
carbon cycle processes: fossilisation - Answer>> - incomplete
decomposition of dead organic matter under anaerobic conditions
can produce substances that form substances that have a high
carbon store
, carbon cycle processes: combustion - Answer>> - burning
organic material to release carbon dioxide
carbon cycle: human impacts: changes to photosynthesis -
Answer>> - deforestation reduces the movement of carbon
from the atmosphere into biomass
- afforestation increases the movement of carbon from the
atmosphere into the biomass
- marine pollution with toxic materials can reduce phytoplankton
populations which then reduces the absorption of dissolved
carbon dioxide
- carbon dioxide in the atmosphere would have dissolved in the
sea to maintain the balance between CO2 in the atmosphere and
the sea
- more toxic pollution that kills the phytoplankton leads to an
increase in atmospheric carbon dioxide levels
- algae that live on the underside of ice, some of the carbon
dioxide they absorb sinks to the seabed in the faeces of krill that
eat the algae
- if climate change reduces the sea ice then less CO2 may be
removed from the sea
carbon cycle: human impacts: changes in aerobic respiration -
Answer>> - carbon in DOM is gradually released as CO2 by
aerobic respiration of soil organisms--> bacteria and fungi
- ploughing increases the oxygen supply to decomposers so
aerobic decomposition takes place more rapidly
- the amount of carbon in the soil of DOM is reduced and amount
in atmosphere increased
carbon cycle: human impacts: changes in anaerobic respiration -
Answer>> - anaerobic soil organisms release methane gas
