MadSci Network: Biochemistry |
Dear Alle,
Thanks for your question. When plotting graphs, the convention is that you plot the independent variable: the variable over which you have control, on the x-axis (also called the abscissa). The dependent variable - the variable which you are measuring as a function of your known, controlled variable - is plotted on the y-axis (also called the ordinate).
In the case of a standard curve, the standards are known protein concentrations upon which the absorbance is dependent. So your initial idea was the correct one. Ideally, you will obtain a best-fit straight line through your points and be able to use the equation y = mx + c to obtain the concentration of the unknown sample from its absorbance.
In practice, switching the axes will make no difference to the calculation provided that you remember which is x and which is y. However, the convention is as I described and best followed to avoid confusion.
Hope that helps,Links
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