Biology 2.2.13: Practical Biochemistry 2: Quantitative Tests For Biological Molecules

Question 1

what does a colorimeter measure?

Answer 1

absorbance/transmission, the paler the solution the lower the absorbance and the higher the transmission, as more light can pass through substance

Question 2

how do you use a colorimeter to find the unknown concentration of reducing sugars?

Answer 2

carry out a Benedict’s test on a range of standard solutions of reducing sugar. using the colorimeter, measure the % transmission of each sample starting at 0.0 each time by using a cuvette of water and shining red light through, then plot a graph of transmission against concentration , now carry out Benedict’s test on the unknown solution and measure the transmission the same way as before, plot the transmission on a calibration curve, and read x-axis for conc. of unknown solution

Question 3

what indicates a higher reducing sugar concentration?

Answer 3

higher absorbance, lower transmission