[ 537 ] Physical Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • A student is following a chemical assay to measure the amount of protein in a sample. The reaction turns blue in the presence of protein. She runs known solutions of protein plus an unknown and measures the amount of blue color or absorbance in a device called a spectrophotometer. The results are shown in the table and graph. 1.2 1 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 60 Protein (mg) Absorbance (arbitrary units) The line formed by the data from the protein standards is called a standard curve. How much protein is in the unknown sample? ____ μg