Nutrient Cycles Flashcards
Advantage of using dry mass and not fresh mass to compare yield of plants
Water content variable
Will not affect dry mass
Carbon sink
Takes up CO2
Fossil fuel
Global warming
Increase in earths temperature
Co2= greenhouse gas
Which traps infra red radiation
Increases greenhouse effect
Melting ice caps+ climate change
Describe role of saprobionts in nitrogen cycle
Secrete extracellular enzymes via exocytosis to decompose proteins/dna/rna
Releasing ammonia into the soil
(AMMONIFICATION)
Explain how carbon-containing compounds are absorbed and used for growth by saprionionts
Extracellular digestion
By secretion of enzymes
Absorption of digested products (amino acid)
Synthesis of dna/rna/proteins
Respiration provide energy for growth
Nitrogen compounds made available to for main crop after ploughing
Describe the role of microorganisms in this process
Proteins broken down
Ammonifcation
By saprobionts
Conversion of ammonia to nitrites to nitrates
By nitrifying bacteria
Nitrates absorbed into the roots via active transport
Why Up g-1 units used
Allows comparisons
Easier to plot
Give examples of molecules containing nitrogen
Amino acids/protein
Base
Dna
Rna
Atp/ ADP
NADP
NAD
chlorophyll
Describe why phosphates needed for growing plant
PRODUCTION OF
phospholipids in cel membrane
DNA
RNA
NADP
Synthesis of ATP
Describe how lack of phosphate in the soil surrounding a plant can affect its growth
Phosphate required to produce ATP so LESS respiration less energy for growrh
REQUIRED to synthesis DNA/mRNA so less cell division/protein production
REQUIRED to make RUBP/NADP so less CO2 reduced INTO SUGAR
REQUIRED to make phospholipids for membrane
Outline advantages of having mycorrhizae near plants
Mycorrhizae helps plants to defend themselves ( causes an increase in crop yield)
Mycorrihzae helps plants take up phosphate (increase in growth and crop yield)
3 samples of water from 3 diff rivers
Outline how to obtain qualitative measurement of their cloudiness
Use of colorimeter
Measure absorbance of light
Same volume of water for each sample
Biomass
Total mass of of carbon
Dry mass of tissue per given area in a specific time
Suggest what you should do to ensure all water is removed from a sample
Regularly heat and weigh until mass is constant
GPP
Chemical energy store in plant biomass in a given area or volume
NPP
chemical energy store in plant biomass after respiratory losses
NPP= I - ( F+R)
Percentage of light energy trapped by producers is low
Why
Some of the light energy is reflected
Some absorbed by water vapour
Some light energy wrong wavelength
Some fails to strike chlorophyll
Biomass of primary consumers less than biomass of secondary consumers
Why
Energy lost through respiration
Energy lost through heat
Energy lost in excretion (urine)
Some parts inedible so energy lost through faeces
Describe and explain why the efficiency of energy transfer different st different stages in transfer
Some light energy fails to strike chlorophyll
Some light energy relfected
Efficiency of photosynthesis in plants low
2% efficient
Respiratory loss
Loss as heat
Efficiency lower in older animals
Carnivores use more of their food than herbivores
Explain how domestic livestock increases net productivity
Slaughtered when still growing/ before adulthood so more energy transferred into biomass
Fed on concentrated diet so more food absorbed so less energy lost thru faces
Movement restricted so less respiratory loss
Kept inside to reduce heat loss
Genetically selected for high productivity
Describe the need for plants to photosynthesise and respire
In the dark no atp production in photosynthesis
Some Tissues unable to photosynthesise
ATP cannot be stored
Plants use more atp than produced in photosynthesis
Atp for AT
ATP used for synthesis of protein
Conc of CO2 changes in the air st different heights in a period of 24 hours
Why
Explain using photosynthesis
High conc of CO2 in the dark
No photosynthesis in the dark
In dark plants respire
In light net uptake of CO2 by plants
Rate of photosynthesis greater than rate of respiration
Decrease in CO2 conc with height
Ar ground level fewer photosynthesising tissue
Natural vs agricultural ecosystems
Natural ecosystems recycle their inorganic ions but agricultural the crops are harvested/removed so less recycling of inorganic ions
*nitrogen required to produce proteins and DNA foe growth so less growth
Whats erosion
Once rock has been weakened and broken by weathering it can be moved to another place by ice wind or gravity
In the phosphorus cycle wat is NOT involved
Gases
Downsides of monoculture
Diseases and insects can spread from plant to plant quickly
Reducing biodiversity through loss of niches reduction in variety of food sources
Phosphorus cycle
Phospholipids, RNA + DNA from dead organisms into phosphate ions
Decomposed by saprobionts
Phosphate ions also found in waste and remains e.g bones
Phosphate ions transported by streams rivers and lakes
Form sedimentary rock
Weathering and erosion of rocks helps phosphate ions dissolve in ocean+lakes+soils
Phosphate becomes ready for absorption by plans to incorporate into new biomass
Describe eutrophication
Nitrates flushed into water courses
Increased algal bloom
Light blocked out
Algae die unable to photosynthesise
Aquatic plants unable to photosynthesise and die
Increase in saprobionts so increase in aerobic respiration
Aerobic organisms die as lack of O2
Increase in anserobic microoganims
Release of toxins=putrid conditions
Purification ponds only work efficiently when they are shallow and warm
Why
Sufficient light for photosynthesis
Warmth leads to faster enzyme activity so faster bacterial respiration+decomposition
So faster photosynthesis as respiration produced CO2
Increased growth
Explain advantage of having both algae and bacteria in a purification pond
Breakdown organic matter by enzymes
Ammonia used by algae to make proteins
Bacterial respiration uses O2.
Respiration produces energy for growth of bacteria
Reasons for conserving woodlands
Conserving habitats and niches
Increases biodiversity
Tourism
Reduces erosion
