5.3, 5.4 Energy / nutrient cycles

How to extract photosynthetic pigments and separate them using chromatography

1. Add leaf to pestle and mortar. Add low boiling point, polar solvent a few drops at a time and crush into a slurry.

2. Add chlorophyll solution using capillary tube to chromatography paper with origin drawn with a ruler and pencil.

3. Place paper in solvent

4. Leave for solvent to travel paper

Rf Value

Retention factor

(Distance pigment travelled from origin / distance solvent front travelled from origin)

Producers

Plants and algae that access sunlight energy directly

Consumers

Animals obtain the energy indirectly from the consumption of plants

Decomposers

• Bacteria and fungi obtain the energy from the decomposition of dead plants and animals

• aka saprabionts

• feed on dead organic matter

• secrete digestive enzymes out of their cells

• extra cellular enzymes hydrolyse large, insoluble organic molecules into small, soluble molecules

• small, soluble molecules are absorbed into cells

A: extra cellular enzymes

B: extracellular digestion

C: small, soluble molecules

How 99% of energy is lost from the sun

Some light is reflected off the surface of the leaf

Some light is transmitted through the leaf without hitting the chloroplasts

Not all wavelengths of light absorbed are used in photosynthesis

GPP

gross primary production

total mass glucose produced in photosynthesis by producers

NPP

net primary production

total mass of glucose remaining after glucose used in respiration is removed (lost as heat)

biomass

total mass of living material / organic molecules in organism

what % of energy is passed to the next energy flow stage

10%

How is 90% of energy lost through the energy cycle stages (5)

Not all biomass is eaten

Not all biomass is digested

Dead tissue

Faeces and urine

Some biomass used in respiration to provide ATP for metabolism, lost as heat

N = I - ( R + F)

N = net secondary production

I = biomass ingested

R = Respiratory losses

F = energy lost as faeces and urine

Organic forms in phosphorous cycle (4)

• phospholipids

• ATP / adp

• dna / rna

• nadp

inorganic forms in phosphorous cycle

Phosphate

Draw the phosphorous cycle

How does DNA in consumers come from DNA in producers?

Ingestion, digestion, absorption, assimilation

Proteins in saprabionts from proteins in consumers

Death and decay

Urine and faeces

Proteins in saprabionts from proteins in producers?

Death and decay

Draw the nitrogen cycle

Organic forms in the nitrogen cycle (5)

Amino acids / proteins

DNA/RNA

ATP

NADP/NAD/FAD

urea

Inorganic forms in nitrogen cycle (4)

Ammonium ions (NH4+)

Nitrite ions (NO2-)

Nitrate ions (NO3-)

Atmospheric nitrogen (N2 gas)

Ammonification

Saprobiotic bacteria convert amino acids (and urea)

Into ammonium ions (NH3 from amino acid to NH4+)

phosphate ions from saprabionts to DNA in producers?

Phosphate ions are released from the DNA of saprabionts to soil

Are uptaken and incorporated into the DNA of producers

Nitrification

Nitrifying, aerobic bacteria convert

Ammonium ions to nitrites to nitrates

Denitrification

Denitrifying, anaerobic bacteria convert nitrates to atmospheric nitrogen

Nitrogen fixation

Nitrogen fixing bacteria convert atmospheric nitrogen to ammonium ions

Nitrogen fixing bacteria (4)

• some are free living in soil

• Others have a mutualistic relationship with plants

• Eg legumes (peas, beans, clover)

• Found in root nodules

Mutualistic relationship between nitrogen fixation bacteria and legumes

• plant uses NH4 to synthesise amino acids

• bacteria obtains sucrose to be used as respiratory substitute

Eutrophication

• inorganic fertilisers contain NH4+ and PO4 3-

• highly soluble, ions are leeched into aquatic ecosystems

• increase in NH4+ and PO4 3- leads to algal bloom

• prevents light getting to plants, they can’t photosynthesise

• saprabionts decompose dead plant material, their population increases

• bacterial respiration leads to deoxygenating of water

• oxygen sensitive species die