practical 8 in a test-tube

In practical 8 you will be practising preparing a protein solution, making a standard curve and looking at how absorption spectra change between oxidised and reduced haemoglobin... 

During this lab you will be:

• practising concentration calculations
• making up a protein solution of known concentration
• performing a serial dilution of your protein solution
• using your set of diluted protein solutions and a spectrophotometer to create a standard curve
• using your standard curve to find the concentration of a protein solution of unknown concentration 
• Using the spectrophotometer to look at how the absorbance properties of oxidised and reduced haemoglobin differ

The day will be divided into the following activities:

Activity 1 : You will prepare a protein solution of known concentration, and then from this you will perform some serial dilutions of your protein solution so you have a set of protein solutions of decreasing protein concentration. You will find the absorbance of these protein solutions.
Activity 2 : You will draw a calibration curve relating protein concentration to absorbance. You will use this standard curve to find the concentration of a protein solution that you make up yourself, and then you will use the standard curve to find the concentration of a protein solution of unknown concentration. 
Activity 3: You will be looking at what happens to the absorption properties of haemoglobin, when it is both oxidised and when it is reduced.

These exercises have been designed to make you think about what you are doing - for example, what is the best way to make a solution of very low concentration when you are starting with a powder of the compound? 

Also, you will notice that there are not too many activities this week. This is to allow you to really think about what you are doing, refine your techniques and it will give you time to ask questions on anything you have been struggling with up to this point.

See you Tuesday!