One OD unit of A260 is 50 ug/ml dsDNA. You have 2.75 ml genomic DNA (stock). You took 5C ul of the DNA sample and mixed it with 950 ul water and measured the A260 absorption. The diluted sample absorbed 0.14 units of A260. The DNA concentration of the stock is ug/ml, considering the dilution factor of - (Note: ug= microgram, ul- microliter). O 70/10 O 140/20 O 280/50 O 560/100

You have run a gel with 5 uL of amplified DNA in addition to 1 uL of 6X loading dye. Comparing the brightness of this band to your marker, you estimated that your amplified DNA is approximately 62 ng. What was the concentration of your amplified DNA that was loaded? You do not need to account for the volume of loading dye in your calculations.

When pure hemoglobin (molecular mass of 64,000 Da) is separated by the following methods, what major molecular mass species do you expect to see?  Gel filtration chromotography: Gel filtration with 6M Urea: SDS-PAGE with DDT: SDS-PAGE:

Calculate the viral titer of an experiment performed yielding a pfu of 279 from plating 1.0 ml of the 10-5dilution.  Show all work and write the answer in scientific notation.

The data in the table are used to create a calibration curve for the determination of RNA from ts absorbance at 260 nm. Use a spreadsheet and the least-squares method to determine the slope and y-intercept of the best straight line fit to the calibration curve. Do not subtract the blank reading when creating the calibration curve. m = b = RNA (µg) 0.00 10.36 20.72 31.08 41.44 Absorbance at 260 nm 0.268 0.497 0.795 1.131 1.373 Hig Using the slope and intercept of the calibration curve, determine the quantity of RNA in a sample that gives an absorbance of 0.699.

A plaque assay is performed beginning with 1 mL of a solution containing bacteriophages. This solution is serially diluted 3 times by combining 0.1 mL of each sequential dilution with 9.9 mL of liquid medium. Then 0.1 mL of the final dilution is plated in the plaque assay and yields 12 plaques.What is the initial density of bacteriophages in the original 1 mL? Enter your answer to two significant figures ( for example: 1.1 * 10^2)

Blood pH averages 7.4 but fluctuates from7.35 to 7.45. A pH of 7.4 can therefore beconsidered----------- the for this variable.

Several cell culture lines of epithelial cells, called “Cell Line A, B, or C,” are incubated with 104 infectious particles of influenza virus, and viral titers in the culture media are measured 2 days later. Looking at the results of this experiment, it is apparent that the three lines do not all show the same response to the virus. To investigate these differences, mixing experiments are performed, where cells from two different cell lines are mixed together at a 1:1 ratio before the Influenza infection.  Based on the results shown in the figure below, propose an explanation for these data.

Determine the concentration of monocytogenes enumerated from the apple slice based on the information below. You must draw your serial dilution and show your mathematical calculation to receive full credit. The apple slice (12 g) was first mixed with 108 ml of sterile 0.1% peptone water. After, 1 ml was added to tube containing 9 ml of sterile 0.1% peptone water. Process was repeated with two additional tubes. 1 ml was pipetted from tubes 2 and 3 onto MOX media. Plates were incubated at 37 for 48 hours. The pictures below show the plates from tube 2 (left) and tube 3 (right).

A student conducted an experiment on protein isolation from mungbean. After isolating the protein, the student characterized the isolate using the Bradford assay. Standard solutions of bovine serum albumin (BSA) were prepared and 0.1 ml of each solution was subjected to Bradford assay. Absorbance readings were made at 595 nm and summarized below. Concentration of Absorbance at BSA (mg/mL) 595 nm 1.2 1.12 1.0 0.97 0.8 0.79 0.6 0.59 0.4 0.37 0.2 0.17 The student found out that 0.1 mL sample of the protein extract from mungbean gave an absorbance of 0.83 in the same assay. 1. How much was the concentration of the protein in the mungbean sample (in mg/mL)? Show all equations and calculations. 2. Draw a graph for the readings of the standard solutions and absorbances. Indicate the approximate location of the calculated concentration of the mungbean sample in your graph.