Final answer:
In biology, protein concentration can be measured using absorbance readings. The concentration can be calculated using Beer's law and the molar absorptivity. For example, the concentration of a DNA sample can be calculated using the maximal absorbance at 260 nm and the molar absorptivity for DNA.
Step-by-step explanation:
In biology, the concentration of proteins in a sample can be measured using a chemical assay that changes color depending on how much protein is present. The more protein present, the darker the color. The amount of color can be measured by the absorbance reading.
To calculate the concentration of the sample, you can use the equation A = ɛlc, where A is the absorbance reading, ɛ is the molar absorptivity (extinction coefficient), l is the path length (usually 1 cm), and c is the concentration of the sample (in mol/L).
For example, if you have a diluted DNA sample with a maximal absorbance of 0.326 at 260 nm, you can use Beer's law and the molar absorptivity for DNA, which is 14,150 M¹cm¹, to calculate the concentration of the original DNA sample.