Conclusion from scatter diagram
Many results lie a long way off the line of best fish
Explanation of increase in number of water beetles due to presence of fish in lake
There is a greater selective pressure, so beetles are forced to adapt.
Therefore there are more species.
Fish produce an acidic environment as they release CO2 during respiration
Presence of predators increases the birth rate of the population as more offspring are needed to survive to reproduce
Suggestion of function of hydrogen sulfide in bacterial alternative form of photosynthesis
Hydrogen sulfide .. breaks down to form glucose
..can be split into glucose, sulfur and water
Bacteria use the hydrogen sulfide to create ammonium-containing compounds
Explanations of evolution in giraffes
Different habitats are different colours
The advantageous alleles survive and reproduce
As more survived and reproduced the allele for mutation was passed on
Different skin colours and markings would then prevent reunited populations from interbreeding
Humans may have built a road separating these giraffes into different groups
Giraffes had different markings showing who they could mate with
Use of mitochondrial DNA (mDNA) to demonstate different species
Mitochondrial DNA is inherited only by the mother
mDNA of 6 subspecies was so different that the different subspecies DNA would not survive with the other's
mitochondrial DNA
mDNA of same species would be the same length ..have same number of chromosomes
They may have had different numbers of chromosomes in different species
mDNA
- contained different amino acids
- contains info used to make gametes
- contains aerobic enzymes
- was taken from the egg of female
- could be incorporated into surrogate giraffe
ATP made in the mitochondria might have been different in the 6 subspecies
They separated the DNA into its separate amino acids
This would have resulted in respiratory problems for offspring
Only the strongest alleles of genes would be passed on
This would allow comparison of rates of respiration
Better camouflaged giraffes have less mitochondria - others would need to run from predators
They compared how much ATP each subspecies produced
Because DNA codes for organisms ,,,
The different amino acid sequence in the DNA of the six determine that these species are more different from each other
How micro-organisms processing household waste contribute to the increase in temperature
When decomposing waste, microbes will have been respiring and hence generating heat from muscles used in respiration
Advantages of showing data using standard deviation rather than ranges
Ranges uses extreme values which does not include the majority of the data
SD is not affected by extreme values
Evidence for succession
Gram positive rods started low and increased as time went on
Explanation of respiratory quotient results
Seeds who are respiring need more oxygen to be able to respire
This suggests respiration was higher than intake of oxygen
Why aerobic respiration produces more ATP than anaerobic respiration
Oxygen is used to move large amounts of H+ ions through ATP synthase
Aerobic respiration involves a longer process e.g. the Calvin cycle and so it needs more ATP to keep the process continuing
Anaerobic respiration is used over a shorter time so uses glucose less well e.g. exploits it less
In anaerobic respiration the Kelvyn cycle can't occur
Aerobic respiration uses the CO2 to form more energy
In anaerobic respiration the organism has to have the energy in the first place to form the ATP
Krebs cycle happens twice - glycolysis only happens once
In aerobic respiration, phosphorylated oxidation takes place
Avoiding bias?
Place a transect square at the co-ordinates
Generate co-ordinates from random computer generator
Explanation of differences in algal species at 2 points on seashore
More light may cause algae to lose water via their stomata
If it is humid there is less oxygen in the air
Site may differ in pH concentration
Algae needed a lower temperature so less energy was wasted in maintaining it
The closer to the sea the more salt in the soil
More light means it is more likely to photosynthesise
Algae on the upper shore may photosynthesise more easily due to lack of water to refract light
How scientists determined the loss of mass of algae due to respiration
In the lab everything is equal
They mave have kept a measure of the oxygen released into the tank
Measure the mass of alga before and after evaporating it.
This would show the loss of water due to respiration as water is produced by respiration.
If the liquid in the tube moved to the right that would show that carbon dioxide is being produced
- By testing the acidity in the tank before and after the experiment
- Using gas syringe
- Respirometer
- Counting bubbles
- By measuring temp change
- Place in tank of KOH solution
- Measure amount of ethanol produced
The difference would be the amount of algae that was eaten and therefore not respiring
Conclusions to data about amounts of algal species being consumed by sea slug and shore crab - using probability values
Each alga ate both the sea slug and the shore crab
The significant value was less than 0.01 suggesting they were 99% confident
The final alga had p < 0.05 so it was significantly eaten
One alga had a critical value that left 1% to chance
Two algae are in the acceptable range for probability of error
There is a greater than 5% chance that these results are down to probability
0.05 is a very small number so the results are accurate
Light-dependent reaction explained
Photons of light strike the chlorophyll in the chloroplasts
and this causes the excitement of the electron
Electrons are excepted by an electron carrier
Water is hydrated to produce oxygen
Light energy also causes the phosphorylation of water
As the H+ ions try to create balance they move through ATP synthase
ATP synthase adds an independent phosphate to ADP
Light difffuses into the cell via the stomata and into the thylakoids
Light has electrons present that contribute to making OH- and H+
These e- are transported in electron carriers to higher levels so e- has more energy
Light enters the chloroplast via the stomata
Energy released from falling elecrons is used to reduce NADP
Advantages and disadvantages of chemical pesticides
Nitrate pesticides cannot be used in organic farming
Pesticides are not as specific so they kill other pests
Its not specific so it kills both good pests that help the growth of plants
as well as the bad pests
They will kill the whole pestilential population
If rainfall occurs then the chemical agents can lead to bioaccumulation
Pesticides are insoluble in water so they can leach into water sources
How soil microorganisms produce nitrates from remains of crop plants
Saprobionts produce nitrates from the remains of the soil
Proteins contain nitrogen as they have nitrogenous bases adenine thymine guanine and cytosine
Ploughing adds oxygenated nitrogen gas to the soil
The microbes use the ammonia and breathe out the nitrogen
These nitrate ions are broken down by saprobionts
Saprobiotic organisms break down the crop plant remains to their original compounds
Nitrogen fixation is when nitrogen gas in the atmosphere is broken down to ammonia
Urea, amino acids and proteins are ammonia containing compounds
Nitrofine organisms convert ammonia into nitrates
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