BSA Concentration Determination Quiz

Protein Quantitation and Assays

• The formula to calculate dilution factor (DF) is not specified in the text.
• The wavelength of maximum absorption of the Coomassie Brilliant Blue G-250 dye when it is not yet bound to protein is 465 nm.
• The Coomassie Brilliant Blue G-250 dye is affected by different pH levels, with varying absorption spectra.
• Upon initial contact with CBB G-250 dye, the protein's conformation changes, allowing the dye to bind.
• The Bradford reagent is prepared by mixing the Coomassie Brilliant Blue G-250 dye with other reagents.
• The UV-visible spectrophotometer measures the absorbance of a sample at a specific wavelength.
• The protein-bound dye absorbs orange light strongly at a wavelength of 595 nm.
• The Beer-Lambert law states that there is a linear relationship between absorbance and concentration.
• If the absorbance of a sample is higher than the absorbance of the standard solution with the highest concentration, the sample may be too concentrated.
• Absorbance should be measured immediately after mixing the dye with the protein sample to avoid errors.
• The correlation coefficient (R or r) measures the strength of the linear relationship between variables.
• The coefficient of determination (R2 or r2) quantifies the proportion of the variance in the dependent variable that is predictable from the independent variable.
• The Biuret Assay produces a purple color.
• In Colorimetric copper-based assays, the absorbance is measured at a wavelength of 540 nm.
• The Lowry Assay primarily measures the protein content in protein samples.
• The Lowry Assay produces a blue color.
• The Lowry Assay can detect lower protein concentrations than the Biuret assay.
• The Folin-phenol reagent reacts with the copper ions in the Lowry Assay to form a chromophore.
• Homology modeling is not directly related to the Lowry Assay.
• The function of the Lowry Assay is to quantify protein concentrations in a sample.
• The best protein to use as a standard in a protein assay is a protein with a known concentration.
• Standard curves made using the same concentrations of 2 different proteins are not the same due to differences in protein structure and composition.
• The Bradford reagent should be stored in a dark place to avoid degradation.
• The incubation of protein solutions after mixing with the Bradford reagent should be done away from light to prevent photobleaching.
• In the absence of an absolute reference protein, a relative standard should be used in a protein assay.
• The purpose of using a protein standard like Bovine serum albumin (BSA) in the Lowry assay is to create a standard curve.
• The formula used to calculate the concentration (x) of a protein sample based on its absorbance (y) in the Lowry assay is y = 0.2869x – 0.0007.
• Protein samples concentrations are unknown in the Lowry assay because the assay is used to quantify protein concentrations.
• The equation y = 0.2869x – 0.0007 represents the linear relationship between absorbance and concentration in the Lowry assay.
• 2 mg/mL is equivalent to 2 ug/uL.
• 2 mg/mL is equivalent to 2000 ug/mL.
• To prepare 500 uL of 2 ug/uL BSA solution, 100 uL of BSA stock solution with a concentration of 10 ug/uL is needed.
• The formula C1V1=C2V2 represents the law of conservation of mass, used in dilution calculations.
• The final volume for a new BSA concentration is 500 uL if 2 ug/uL BSA solution is prepared using 100 uL of BSA stock solution with a concentration of 20 ug/uL.
• The protein's conformation changes upon initial contact with Coomassie Brilliant Blue G-250 dye.
• Coomassie Blue stains proteins by binding to basic amino acid residues.
• The formula to calculate dilution factor (DF) is not specified in the text.