The correct answer is none of the other answers. To increase specificity of the generated antibody, it is beneficial to expose the animal (in which the antibody will be made) to the entire purified protein, rather than a short synthesized predictive peptide. Moreover, affinity purifying the antibody by exposing the bled antisera to the purified protein and separated the bound antibody-protein fraction from antibody and protein alone will increase specificity. Following antibody generation, determining the optimal dilution of the antibody as well as appropriate blocking conditions to compete out non-specific binding with the specimen are necessary. 

The correct answer is sectioning is preferred if the whole-mount is too large in the Z plane to resolve by confocal microscopy. Sectioning takes a small slice of an otherwise large specimen, and then subsequent antibody staining can be performed. Typically, this is preferable when one desires to stain certain cell types/layers or the entire specimen is too thick (large Z plane) to mount on a coverslip and resolve by microscopy. 

The correct answer is the 1200 bp fragment will not image as brightly as the 3500 bp fragment. Ethidium bromide intercalates into DNA proportionally to the size of the fragment. Since we expect the same number of molecules of 1200 bp and 3500 bp fragments, the 1200 bp fragment should be roughly 3 times less bright than the 3500 bp fragment based on the number of ethidium bromide molecules incorporated into the strands. Additionally, smaller fragments migrate more quickly than larger fragments, and as such, are farther from the loading wells. 

The correct answer is ribosomal RNA genes. These genes have highly conserved regions that scientists can use to design primers to amplify intervening regions. These intervening regions, however, are highly divergent and are extremely useful sequences to distinguish between species. 

The resolution of an image is defined as the minimum distance between two points so that they can still be seen as two distinct structures. Resolution is important in microscopy. Images with clear resolution can be distinctly seen as two separate objects within the field of view.

For this problem we need to determine the equation of our standard curve. This can be done by creating a graph from the data points and determining the slope.

Assuming that a sample of zero concentration will also have zero absorbance, we can find the equation for the line generated by finding the slope.

Pick two points on the line to find the slope. We will use (0,0) and (40,0.405).

Use this equation and the absorbance given in the question to find the concentration of the unknown sample.

Bradford assays use shifts in absorption ranges to identify the quantity of a protein in a sample. The technique uses Coomassie blue dye (Bradford reagent) and spectrophotometry to analyze protein concentrations.

qPCR is a procedure that measures the products made from a PCR reaction in real time, and is a helpful tool for studying gene expression. Coimmunoprecipitation is a technique that will isolate a specific protein or protein complex by using an antibody specific to that protein; however, this technique will not quantify a sample without further analysis. Southern blots are used to detect specific DNA sequences in a sample. 

Because he is unaware of exactly where the concentration lies, it would be best to test a few samples before and after his predicted range. This will allow the researcher to ensure that his curve is linear and that his sample fits accurately somewhere along the curve. If his sample falls outside of the range he tested, he will not be able to use his standard curve to accurately predict the concentration of his sample.

The correct answer is the ratio of A₂₆₀/A_280. DNA absorbs light most strongly at 260nm and is used to determine the concentration of the DNA solution. Contaminants such as aromatic amino acids present in proteins are absorbed at 280nm, and as such, taking the ratio of A₂₆₀/A₂₈₀ will indicate the purity of the DNA sample. Typically, a A₂₆₀/A₂₈₀ ratio of 1.7-2 is indicative of good quality DNA. 

The correct answer is to determine the concentration of protein in a sample. Bradford assays are often used before Western blots in order to normalize the amount of protein being loaded between conditions. Briefy, a small volume of protein lysate is mixed with a reagent and the absorbance at 595nm is compared to known concentration controls to determine the relative protein concentration of the sample.