Aim:
To investigate the effect of different light wavelengths on the photosynthesis of immobilised algae.
Equipment:
Method:
We had to immobilise algae into beads so that we could maintain a set mass of algae for each experiment. Furthermore, having the algae in beads meant that the colour of the algae didn't interfere with our qualitative readings from the hydrogen carbonate indicator solution.
1. Leave your algal culture to settle for 30 minutes in a measuring cylinder, then using a pipette take 5cm3 of the algal culture from the bottom of the measuring cylinder where the algae has settled.
2. Mix 5cm3 of algal culture with 5cm3 of 3% sodium alginate solution. Take up the algal culture and sodium alginate solution in a syringe.
3. Clamp the syringe above a beaker of calcium chloride solution.
4. Remove the back of the syringe which allows the solution to drip into the calcium chloride and form beads in the beaker.
5. Allow the beads to harden for a few minutes before straining them out of the beaker through a tea strainer
6. Rinse the beads in distilled water to keep the algae alive.
7. Rinse 6 translucent bottles with hydrogen carbonate indicator solution
8. Add 20 algal balls to each container
9. Add 5cm^3 indicator to each container
10. Surround each bottle with different coloured light filters apart from one with no filter.
11. After a few days note the colours of the indicator and compare it to your action spectrum.
To investigate the effect of different light wavelengths on the photosynthesis of immobilised algae.
Equipment:
- light filters of different colours
- 3% sodium alginate solution
- Algal culture
- Hydrogen carbonate indicator solution
- 50cm^3 syringe
- Clamp
- calcium chloride solution
- beaker
- tea strainer
Method:
We had to immobilise algae into beads so that we could maintain a set mass of algae for each experiment. Furthermore, having the algae in beads meant that the colour of the algae didn't interfere with our qualitative readings from the hydrogen carbonate indicator solution.
1. Leave your algal culture to settle for 30 minutes in a measuring cylinder, then using a pipette take 5cm3 of the algal culture from the bottom of the measuring cylinder where the algae has settled.
2. Mix 5cm3 of algal culture with 5cm3 of 3% sodium alginate solution. Take up the algal culture and sodium alginate solution in a syringe.
3. Clamp the syringe above a beaker of calcium chloride solution.
4. Remove the back of the syringe which allows the solution to drip into the calcium chloride and form beads in the beaker.
5. Allow the beads to harden for a few minutes before straining them out of the beaker through a tea strainer
6. Rinse the beads in distilled water to keep the algae alive.
7. Rinse 6 translucent bottles with hydrogen carbonate indicator solution
8. Add 20 algal balls to each container
9. Add 5cm^3 indicator to each container
10. Surround each bottle with different coloured light filters apart from one with no filter.
11. After a few days note the colours of the indicator and compare it to your action spectrum.
before the experiment.
place your vials in the same place where they will receive equal levels of sunlight.
our results.
Analysis:
As can be seen our results don't show a large colour difference in the indicator solution.
If the algae have a net rate of photosynthesis over respiration then carbon dioxide will be removed from the solution and thus the indicator will go purple. If there is a net exchange of respiration over photosynthesis then oxygen will be removed from the indicator and more carbon dioxide added tot he indicator and thus it will go yellower in colour.
I think the reason my results didn't work was because i put the beakers in a shaded area that didn't receive much sunlight. This meant that photosynthesis could not occur as the light dependent stages of the reactions couldn't be undertaken thus the solutions turned yellow as the rate of respiration was bigger than the rate of photosynthesis.
As can be seen our results don't show a large colour difference in the indicator solution.
If the algae have a net rate of photosynthesis over respiration then carbon dioxide will be removed from the solution and thus the indicator will go purple. If there is a net exchange of respiration over photosynthesis then oxygen will be removed from the indicator and more carbon dioxide added tot he indicator and thus it will go yellower in colour.
I think the reason my results didn't work was because i put the beakers in a shaded area that didn't receive much sunlight. This meant that photosynthesis could not occur as the light dependent stages of the reactions couldn't be undertaken thus the solutions turned yellow as the rate of respiration was bigger than the rate of photosynthesis.