BIO 實驗

You are provided with THREE different sugars - starch, sucrose and glucose.
Then you should know that this experiment aims at investigating the effects on respiratory rate of yeast with different sugars.

Ok, now you have got the aim of the lab, whereas it would be the dependent variable, all of the other factors should be independent variable, in which they are said to be kept constant.

To start with, you should prepare 5 test tubes, add 0.5 - 1.0 ml the sugars into the tubes and one with water (as the control).
Secondly, add an adequate amount of yeast suspension in all tubes.
Thirdly, pipette the solution with a filler, leave the pipettes inside the tubes.
(* The solution should be left inside the pipettes)
Next, fold the rubber tubings and clip it.
The following one is a bit tricky, remove the filler and quickly block the opening with you finger.
Then apply the tubing instead of your finger, record the readings from the pipette.
After 20 - 30 mins, check the readings and obtain your results.

Try to find out the mechanism underneath by yourself.
(Hints : think of pressure)