Controlled experiment

Question

Evidence indicate that oocyte maturation or germinal vesicles breakdown (GVBD) in amphibians is induced by progesterone in a time and doses dependent manner.
Hypothesis: progesterone is able to also induce GVBD in fish.
Experiment:
Materials: fish ovarian oocytes, progesterone (dissolved in EtOH) various doses (1; 10; 100 µg/ml), culture media, room temperature, culture time = 24Hr.
What are the controlled, dependent, and independent?
How would you design a controlled experiment?
What is/are the control group and experiment or test groups?

Answer 1

Marry,

 

Each experiment has a positive and a negative control.

 

In your case you need a positive control to make sure that your progesterone is active and functional.

 

You have to find out from literature the concentration of Progesterone that would induce GVBD in frog oocytes.

 

Based on that you would set up a positive control experiment with frog oocytes and defined progesterone solution to incubate for a time period and observe GVBD. For this positive control, you would set up a negative control with no progesterone, frog oocytes incubated in buffer. This negative control should not show GVBD.

 

Now you set up your real experiment with fish oocytes, a number of concentration for progesterone solution at same time and temperature. You would set up a negative control with buffer only and no progesterone. You have to look for GVBD to prove or discard your hypothesis after you obtain same or highly similar results with at least three different experimental set up. 

 

Hope this helps.