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Method
ResultsThe picture taken shows examples of the colours produced by the pH hydrogen carbonate indicator, compared to some standard hydrogen carbonate solutions. The vial that was without a coloured filter turned a deep purple colour. From the pH scale this shows the pH in that vial was at roughly 8, meaning it is in an alkali solution. This is because all wavelengths of light were able to penetrate the vial so that the algae in the vial could photosynthesise at its greatest rate. Therefore the production of CO2 in the vial was at its greatest leading to the greatest colour change. However the vial which had the green filter on, the colour has stayed yellow suggesting a pH of around 7. This is because that the green filter prevented all wavelengths of light other than green from penetrating the vial. Therefore the lowest light intensity is being absorbed by the plant so the least amount of photosynthesis is occurring. So the lowest concentration of CO2 is being produced. From the graph above we can see that green spectrum (around 520-550 nm) and since the alga cannot photosynthesis. This explains why the algal balls in this spectrum didn't produce much CO2.
Equipment
SafetyBecause soda lime is very corrosive, eye protection must be worn at all times during the experiment. A spatula should also be used to remove the soda lime from the container. Maggots can also carry pathogens on their skin so you should wash your hands carefully after handling them. Method
ResultsFrom the results there is an optimal temperature for the rate of aerobic respiration at 40 degrees. This shows that respiration is an enzyme controlled reaction meaning that the rate of respiration is very slow at low temperatures and at temperatures above 40 degrees the active site becomes denatured which halts respiration since the substrate is unable to bind with as there is no induced fit. At the lower temperatures where a little respiration still occurs, there isn't enough energy for the substrate molecule bind to the active site. Therefore the rate is very slow. Secondary ResearchFrom secondary research I have learnt that the increase in respiration is due to the increase in metabolic rate as a result of the increased kitentic energy, allowing reactions to happen at a greater rate as collisions between molecules will happen more frequently so there's a higher chance that the collide with sufficient kinetic energy and at the correct orientation. I also learnt that te size of the organism also has a large affect on the rate of respiration so it is important to control that when considering how to keep my experiment valid. I did this by carefully selecting maggots of a similar size.
http://science.sciencemag.org/content/293/5538/2248 |