Quantitative determination of protein concentration using the biuret test
Name: Chloe Charlotte Farrell Hunt
Prac session: MPM
Q 1. In this practical exercise you will be using biuret reagent. Why is biuret reagent used in this practical?
Biuret reagent is used because it is a solution of alkaline copper sulphate, which reacts with compounds containing peptide bonds to give a violet-coloured complex. The intensity of the colour is a measure of the number of peptide bonds, and therefore an indication of the amount of protein in each sample. From this we can determine whether a plant raised in the sun or a plant raised in the shade will have a higher protein concentration.
Q 2. What is the experimental reason for constructing a standard curve?
A standard curve is used as it can be used to determine the protein concentration of an unknown solution by finding the protein concentration that corresponds to the absorbance reading obtained for that unknown solution. Multiple samples with known properties are measured and graphed, which then allows the same properties to be determined for unknown samples by interpolation on the graph.
Q 3. Based on the above information (in the prac manual) and your own thinking, which plant do you hypothesize will have more rubisco, one raised in the sun or one raised in shade?
I hypothesize that the plant raised in the sun will have more rubisco, because a plant raised in the sun will absorb more light and photosynthesize more rapidly, therefore have a higher protein concentration of rubisco than the plant raised in the shade.
Q 4. Should the line connect all the data points or should it be a line of best fit? Why? (2 sentences)
The line should be a line of best fit, as it will show the average path of the data. It would also represent more accurate results if there were to be experimental errors therefore eliminate outliers within the data affecting the...