Investigating the Rate of Respiration in Yeast: Triple/double science Biology coursework for GCSE - page 3
Keywords: Investigating the Rate of Respiration in Yeast: Triple/double science Biology coursework for GCSE, anerobic respiration, A, Higher Level
By Glamurus on 02/11/2006 17:54:57
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 3 of 6 pages: 1 2 3 4 5 6
repeats of each glucose concentration.
Prediction of Results
I think that the higher the concentration of glucose is, the more gas will be produced. However, there will be a point when the yeast has all the glucose it can use to respire anerobically, so the results after that point will remain the same.
Graph Prediction
Collision theory states that the more energy molecules have, the more often they collide with one another, and so the more times molecules will react with one another. I have predicted a positive correlation increase in the first half of the graph because section 1 is where more energy is available to the enzymes as glucose concentration increases. The increased number of collisions means that there is an increased number of reactions so more carbon dioxide gas is produced. Section 2 is where enzyme theory is used to make the graph prediction. This theory compares enzymes and substrates to a lock and key. The idea is that the substrate for a particular enzyme attaches to that enzyme like a lock and key – only one key will fit in a particular lock; only one substrate will fit with a particular enzyme. Substrates can react with enzymes over and over again. Once all the enzymes in the yeast have reacted with the substrate, no more are needed. At this point, the amount of carbon dioxide gas the yeast enzyme produces will be the same however much the glucose concentration is increased because the actual reaction rate won’t increase. For this reason section 2 of the graph is a flat plateau.
Table of Results
Volume of gas (cm³)
Concentration of Glucose (%) Repeat 1 Repeat 2 Average
10 1.8 3.2 2.9
8 1.9 4.4 3.2
6 4.2 4 4.1
4 1.0 2.9 2.0
2 0.7 5.5 0.7 :
0 0.3 0.2 0.3
: For the 2% glucose concentration, I have not included the 5.5 reading in the average volume of gas because the result is obviously anomalous. It is far higher than any other result. It is also very different to the first repeat’s result (0.7cm³).
Graph
In the first part and the average graph, the trend is that the volume of gas produced increases as the concentration of glucose increases. But after the measurement at 6% glucose concentration, the volume of gas produced starts to decrease as the concentration of glucose increases.
Conclusion
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