Anaerobic Respiration

        

Planning of the Experimental Work:

        Objective:

                The main objective of the experiment was not only to plan a simple, safe method, but also to analyse and record the rate of respiration in yeast, and to find the optimum conditions for it to produce more alcohol and carbon dioxide as waste products from breaking down glucose during anaerobic respiration.  

        Apparatus:

                1 Bunsen Burner

                1 Boiling tube

                1 Test Tube  

                Heat Proof Mat

                Safety Goggles

                Retort Stand

                1 Thermometer

                Accurate balance

                1 gram of Yeast (per experiment)

                1 gram of Glucose (per experiment)

                Lime Water

                Tripod

                Boss + Clamp

                Laboratory Coat

                   Gauze

                  Beaker

        Method / Procedure:

1. Prepare a test tube with 1 gram of yeast and 1 gram of glucose, mixed with enough tap water to fill the test tube up to 2 cm. under the top.
2. Then place bung on the top, with delivery tube connecting to another test tube, with just tap water as well.
3. The first test tube (containing the yeast and glucose) is placed in a water bath; a beaker with water on a tripod.
4. Then place a Bunsen burner underneath, and then when everything is ready, adjust the temperatures to the varied degrees.
5. Continue to do this process until all results are taken.
6. For more accurate results take the experiment with 3 readings for each temperature. (20°C. – 70°C.)

Diagrams:

        

Fair Testing:

        

        I believe that I attempted to make my experiment as accurate and fair as possible by using the best method, to gain and achieve the most truthful and precise set of results.  And therefore by gaining a fair answer, I would definitely be moving towards getting an accurate answer, to the question in mind.

        

        There were many things that required adjustments and changes in my experiment as follows:

                

        I ensured that I used the same pieces of apparatus as much as I can throughout the whole experiment, to have a fairer test.  As changing cans during an experiment, would probably alter results slightly, due to heat being taken into the boiling tube.

                

        I also made sure that the thermometers were checked and regularly changed throughout the experiment.  As if I had used the same thermometer during the whole experiment the results would be inaccurate, as I would have to wait for the thermometer to reach the certain temperatures again.

                

        I made sure that I used the same amounts of yeast accurately, so that I could get the most accurate results.  As if we had more or less water in the boiling tube than we should have, the results would obviously be affected, and the experiment would be very unfair.

                

        Upon looking back at the adjustments made, I believe that I am confident in saying that, I made sure that my experiment was as fair as I could possibly make it.

Prediction / Hypothesis:

        I predicted that the rate of respiration in the yeast would start of at a low rate and as the temperature increased, the rate of respiration would also increase.  Then once at a certain temperature the rate would start to decrease.  These predictions were based on my research from textbooks and from the Internet.  But these predictions should be the basis of my results.

Obtaining the Evidence:

        Safety:

                Safety was one of my main priorities in this experiment, as there was a lot to be aware about.  Firstly there was a lot of hot water about in this experiment, this factor made me change some of my plans in the experiment.

                

        There was also the flames and fires, which needed to be kept an eye on.  This was probably the most dangerous thing or factor in my experiment.  Upon seeing these hazards, I made sure that I was always standing, and not sitting, so that if anything did occur I was able to move myself as need be.  I also made sure that I had a set of Safety goggles on at all times, to avoid any situations, with flames.  I also made sure that I was wearing my laboratory coat at all times, for some sort of protection, to any spilt water or other hazards.

        Results:

                

Analysis of the Evidence:

        Conclusion:

        Looking back upon my results, and experiment on the whole, I think it is fair to say that my investigation was performed with a great standard.  I also found that the rate of respiration gradually increased, before it reached its greatest point (peak).  Then it drops at a very rapid pace, to show the substances have reacted, and that the yeast has respired.  The bubbles slowly continue to be put out, until the substances are totally used.  My results seem to back up this proposal.

                Evaluation:

My experiment in my opinion was performed at the best possible way it could be performed, but there were a few changes, which could have been made.  The accuracy of the results was quite sufficient; however some of my results do seem peculiar.   

The reliability of my experiment was quite fair and supportive

of my results.  The results were as near enough as expected but there were a few anomalies which to alter the curve of the graph. To ensure this we could have possibly performed the experiment more times, for more tests.

The depth of the delivery tube in the test tube could, to a certain extent, affect how many bubbles were released.  Increasing the depth would make it harder for the bubbles to escape; as the pressure was so high.

        If the experiment were to be redone, I would have used different solutions in the other test tube.  A certain possibility was limewater.