# What Affect Does the Concentration of Sugar Have on the Rate of Respiration of Yeast

Topics: Measurement, Glucose, Fructose Pages: 4 (1087 words) Published: February 2, 2013
What affect does the concentration of sugar have on the rate of respiration of yeast? Apparatus:
1. Stopwatch with a resolution of 0.001 seconds
2. 4 test tubes
3. 200 ml of yeast in a beaker
4. 200 ml of glucose solution
5. 500 ml of limewater
6. 2 delivery tubes
7. 1 test tube rack
8. 1 water bath set to 37°C
9. 2 pipettes
10. 3 measuring cylinders with a resolution of 1ml, ranging from 0-30ml. 11. 200 ml of water
Hypothesis:
The higher the concentration of sugar: the faster the rate of respiration. I predict this outcome as the rate of respiration depends upon three main factors: glucose, temperature and oxygen...as the oxygen concentration and temperature remain the same; the increase in the concentration of glucose (sugar) should lead to an increase in the rate of respiration. Variables:

The independent variable for this experiment is the concentration of sugar. The range of the concentration of sugar is 0-100% (inclusive), in intervals of 25%. The chosen range is suitable as it is easy to dilute water with the glucose solutions with the given concentrations and the range is wide enough to see a change in the dependant variable, yet the intervals are equally spaced to allow us to record patterns. The dependant variable is the time taken (in seconds) for the limewater to begin to turn cloudy. In order to make it a fair test, the same person will use the stopwatch to account for reaction times and debates between when the water has begun to turn cloudy. This means that the results will be consistent for each group, and there is less room for human error. We will use a stopwatch with a resolution of up to 0.001 seconds to ensure that the results are as precise as possible. We will also repeat our investigation three times using the same method and equipment to ensure that it is repeatable and we will compare our results with another group’s who have used the same method to see if our results are reproducible. In...