Transfer of energy in an ecosystem Flashcards
Define heterotrophs
Organisms that ingest material from other organisms
Define primary consumers
Herbivores - eat plant material
Define secondary consumers
Carnivores - feed on consumers
Define tertiary consumers
Feed on carnivores
Define trophic levels
Position a species occupies in a food chain
Define detrivores
Primary consumers that feed on dead organic material called detritus
Define decomposers
Species of bacteria and fungi that feed on dead remains and faeces
Define limiting factors
When a process is affected by more than one factor its rate is limited by the factor furthest from its optimum value
in UK main one is CO2 conc
Define GPP
Rate at which energy is incorporated into organic molecules
Total energy transferred from light energy to glucose
Define NPP
Rate at which energy is transferred into organic molecules to make biomass
Total energy left to make new biomass
Whats the equation linking NPP and GPP
NPP=GPP-R
What is the formula for the percentage efficiency of photosynthesis
GPP divided by amount of light energy striking plant x100
What happens to respiration rate?
Doesn’t vary in plants as its fixed rate
Describe efficency
5% reflected
40% absorbed by chlorophyll
50% not absorbed but evaporated
5% transmitted through
Describe producers to primary consumers
2-10% goes to make biomass - not efficient
Not all available food gets eaten due to feeding limitations
Undigested food remains in faeces - cellulose -no enzymes to break it down
Food is used in respiration
Describe primary to secondary consumers
Over 10% of energy in herbivores ends up in new biomass
Most of a herbivore is eaten by carnivore
Why aren’t there more than four or five trophic levels?
Energy entering a trophic level is transferred to surroundings in respiration, transferred to next trophic level or to decomposers
So there’s no more than four or five levels as energy is insufficient to support
What is the thylakoid membrane (CHLOROPLAST STRUCTURE)
Interconnected flattened fluid-filled sacs
Proteins, chlorophyll, electron carriers here
What is the thylakoid space (CHLOROPLAST STRUCTURE)
Fluid in thylakoid membrane sacs with enzymes for photokysis
What is the stroma (CHLOROPLAST STRUCTURE)
Fluid surrounding thylakoid membrane - enzymes for light independent reaction
What is the granum (CHLOROPLAST STRUCTURE)
Stack of thylakoids joined to one another
What is the inner membrane of the chloroplast?
Transported molecules (membrane proteins which regulate the passage of substances in and out of the cell)
What is the outer membrane of the chloroplast?
Permeable to molecules ie H2O and CO2
Describe the light dependent reaction
Light energy is absorbed by PSII and excites electrons
Electrons enter the ETC and move along electron carries in a series of REDOX reactions losing energy in the process
This energy is used to synthesis ATP (photophosphorylation)
Electrons from PSII replace those lost from PSI
Water is split by photolysis and the electron replaces the one lost from PSII
Electron from ATV combine with H+ ions from water and NADP producing reduced NADP
What is the role of ATP?
ATPase catalyses the breakdown of ATP to ADP and Pi
Describe the light independent reaction
CO2 combines with RuBP catalysed by Rubisco
6C compound is unstable so breaks into 2 GP molecules
GP reduced to form GALP - H is from the oxidation of red NADP and ATP provides energy by breaking down
2/12 GALPs form glucose
10/12 GALPS recreate RuBP which is phosphorylated using ATP
