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what is the third stage of the light dependant reaction
The energy released from this causes H+ ions to be pumped into the thylakoid lumen. Due to the concentration gradient, the H+ ions then move out of the ATP Synthase channel by diffusion. This causes ATP to be made from ADP and an inorganic phosphate. The H+ ions and the electron then react with NADP+ to from NADPH
what is oxidation
loss of electrons
what is reduction
gain of electrons
what is photoionisation
When photons 'excites' electrons in chlorophyll, the electrons are released from the Mg within the chlorophyll turning it into a Mg2+ ion.
What do the electrons reduce when they have left the chlorophyll
Electron carriers
what is the electron Transport Chain (ETC)
A sequence of electron carrier molecules that have a lower energy level than the last causing the electrons to loose energy as they move from one to another
what is photolysis and the equation of photolysis
The splitting of water using light energy.
2H2O > O2 + 4H+ + 4e-
what is the first stage of the light dependant reaction
photoionisation
what is the second stage of the light dependant reaction
The electrons then move into another photosystem once they are low on energy. They next move to some electron carriers before moving to NADP reductase. The electrons then leave the thylakoid membrane.
what is chemiosmotic theory
The process of electrons flowing down the electron transport chain and creating a proton gradient across a membrane to drive ATP synthesis.
What is the first stage of the calvin cycle (light independent reaction)
Carbon dioxide diffuses into the leaf through the stomata into the stroma of the chloroplast
What is the second stage of the calvin cycle (light independent reaction)
The carbon dioxide reacts with the 5-carbon compound ribulose biphosphate, catalysed by ribulose biphosphate carboxylase, rubisco
What is the third stage of the calvin cycle (light independent reaction)
The reaction between carbon dioxide and RuBP produces two molecule glycerate 3 phosphate
What is the fourth stage of the calvin cycle (light independent reaction)
NADPH reduces GP into triose phosphate using ATP
What is the fifth stage of the calvin cycle (light independent reaction)
some triose phosphate is converted into carbohydrates while most is used to regenerate ribulose biphosphate
where does the light independent reaction occur
stroma
where does the light dependant reaction occur
thylakoid membrane
what are producers
Photosynthetic organisms that manufacture organic substances using light energy
what are consumers
Organisms that get their energy by consuming other living organisms.
what are primary consumers
herbivores
what are secondary consumers
organisms that eat the primary consumer
what are tertiary consumer
organisms that eat the secondary consumer
giver three examples of a type of tertiary consumer
predators, scavengers and parasites
what are saprobionts
A group of organisms that break down the complex materials in dead organisms, releasing valuable minerals
what is a food chain
A feeding relationship between producers and consumers
what is a food web
a system of interlocking and interdependent food chains.
what is biomass
the total mass of living material in a specific area at a given time
How is biomass measured
in grams per square metre
What occurs in bomb calorimetry
a sample of dried material is weighed and then burnt in pure oxygen within a sealed container. This is then placed in a water bath and the heat from combustion causes a small rise in temperature. This allows the energy released from burning the biomass to be calculated
what is NPP
net primary production is the chemical energy store in plant biomass after respiratory losses to the environment have been taken into account
How do you work out NPP
GPP - R
what is GPP
Gross primary production is the total amount of chemical energy converted from light energy by plants in a given area in a given time.
Why do plants normally convert only 1% of the suns energy into organic material
Not all wavelengths of the sun can be absorbed, light may not fall on a chlorophyll molecule and there may be other factors limiting the rate of photosynthesis
Why is there a low percentage of energy transfer up the food chain
Not all of the organism is eaten, some parts cannot be digested, some energy is lost in waste and energy is lost in metabolic processes
How do you calculate the net production of consumers
N = I - (F+R)
How are ammonium ions converted into nitrate ions in the nitrogen cycle
the ammonium ions undergo nitrification to convert them into nitrite ions. These nitrite ions then undergo more nitrification to become nitrate ions
How does nitrogen in the atmosphere end up as ammonium ions in the soil
nitrogen fixation by free-living bacteria
How do nitrate ions end up as nitrogen in the atmosphere
Denitrification
How do nitrate ions end up s ammonium ions
Nitrate ions are absorbed into producers. These producers then either die or is eaten by an organism which later died. The nitrate ions end up in the soil due to death and waste where saprobionts convert them into ammonium ions in ammonification
what kinds of bacteria carry out nitrogen fixation
Free-living bacteria and mutualistic bacteria
In what plants are mutualistic bacteria found
in the root nodules of leguminous plants
Why does denitrification increase when the soil is waterlogged
There is less oxygen available for aerobic nitrogen-fixing bacteria causing an increase in anaerobic denitrifying bacteria
Give examples of biological components that contain phosphorus
Phospholipids, DNA, RNA and ATP
Describe the phosphorus cycle
Dissolved phosphate ions are absorbed by plants which are eaten by consumers. The phosphate ions then exit the consumer via waste or death. Some phosphate ions become solidified in bones and are released through erosion. Some phosphates are sedimented or deposited into rocks where they are also eroded to be dissolved
What are mycorrhizae
Associations between certain types of fungi and the roots of the vast majority of plants.
How do mycorrhizae benefit plants
Mycorrhizae increase a plant's absorptive surface area of roots. They also act like a sponge, storing water and minerals
What are natural organic fertilizers
fertilizers which consist of dead, decaying remains or plants and animals as well as animal waste
What are artificial fertilizers
Fertilizers which are mined from rocks and deposits
Which fertilizer gives the greatest long term increase in productivity
a mix between organic and artificial
What effect does nitrogen containing fertilizers have on the environment
reduces species diversity, causes leaching and europhication
what is leaching
The process by which nutrients are removed from the soil
why is leaching bad
Leached nitrate ions end up in water sources and can end up in drinking water. It can also cause eutrophication
why is it bad for drinking water to contain high levels of nitrogen
It can prevent efficient oxygen transport in babies
what is eutrophication
excessive richness of nutrients in a lake or other body of water
what is the first stage of eutrophication
Nitrogen ion concentration increases and it is no longer a limiting factor for photosynthesis
What is the second stage of eutrophication
This causes algae on the surface to grow forming an algal bloom
what is the third stage of eutrophication
The algal bloom blocks the sunlight from reaching the plants below causing them to die. This makes the water turn putrid as fish die due to lack of food
what is the fourth stage of eutrophication
Due to the lack of oxygen, anaerobic bacteria populations rise which further causes decomposition releasing even more nitrates and toxic waste into the water
What is glycolysis
the breakdown of glucose by enzymes, releasing energy and pyruvic acid.
