A melt curve analysis was performed to genotype hepatitis C virus (HCV), which has been identified in a patient. When the derivative of fluorescence was plotted versus the temperature for the patient’s isolate as well as for a known genotype of HCV, the two sequences had identical peaks and thus the same Tm. Which of the following is the correct interpretation of these results?

During interphase FISH analysis of a normal specimen for the t(9;22) translocation, one nucleus was observed with two normal signals (one red for chromosome 22 and one green for chromosome 9) and one composite red/green signal. Five hundred other nuclei were normal. What is one explanation for this observation?

Which is a frameshift mutation?

A reference segment of DNA has the following sequence: GCTCACCATGG. Insertion of AG occurs between positions 7 and 8 in a particular genetic disease. How is this mutation denoted by accepted nomenclature?

Protein D consists of 120 residues and forms a dimer through an α-helix at the very C-terminus (residues 100-120). The dimer recognizes a specific 9-base pair DNA sequence. You are purifying the protein in order to determine its structure.   A) For the first step of the purification procedure, describe how you can use an affinity column to capture the protein. You can either design a specific affinity column or a protein construct with a specific tag. In the latter case, specify both the tag and the column that recognizes the tag. (2 pts)   B) For the second step of the purification procedure, ion exchange chromatography is used. The isoelectric point of the protein (PI) is pH 8 and the buffers used for the ion exchange chromatography are at pH 6. Will Protein D be positively charged or negatively charged in the buffers? Should anion or cation exchange columns be used? (2 pts)   C) For the last step of the purification procedure, gel filtration chromatography is used to separate the dimer from a small amount of monomer.  Which species, the dimer or the monomer, will elute first from the column? (2 pts)

A nucleosome consists of DNA and which of the following combinations of histone proteins?

Comparative genome hybridization detects which type of genetic abnormalities?

A protein and its ligand have a Kd value of 10-9 M. If the concentration of both in the cell is 10-8 M, what is the concentration of bound ligand? (2 pts)

 In the TCA cycle, the isocitrate dehydrogenase reaction produces which of the following?  (1.5 pts)

Two enzymes of unknown concentrations, A and B, act on the same substrate, S. The initial velocity (V0) of the reaction catalyzed by Enzyme B is 60% of the V0 for Enzyme A when both enzymes are assayed at [S]= 100 mM. Enzyme A has a Km of 20 mM, and enzyme B has a Km of 100 mM. Both Enzyme A and B have a Vmax of 120 mM/s. (6 pts)   A) What is the initial velocity (V0) for Enzyme A with its kinetic parameters and [S] provided? (3 pts)   B) From these results, can you draw the conclusion on whether Enzyme A’s kcat is higher/lower than or equal to that of Enzyme B? Explain. (3 pts)