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A type of phosphatase can be assayed using p-nitrophenyl phosphate but the assay is performed at pH 7.8, which is the optimum for this enzyme. The initial velocity measured at the highest substrate concentration was .45 deltaA_400 / minute. Convert this velocity to a change in concentration/minute (microM/minute). HINT Use […]

The Meselson-Stahl experiments were groundbreaking studies in molecular biology. Some of the clarity of the centrifugation results was due to the that the DNA was fragmented during handling (although the experimenters did not know it at the time). As quoted in Davis, Stahl said that pipetting DNA was like “throwing […]

The survival of viruses is a great example of natural selection and survival of the fittest. One such example is HIV. HIV reproduces very quickly (about 10 million new viruses per day. HIV lacks the proteins which repair mutations, and therefore there will be many mutations resulting from this rapid […]

A DNA molecule has the sequence shown below. The original DNA does not contain any radioactive labels. The DNA molecule is permitted to replicate in a solution containing all four unlabeled deoxyribonucleoside tripohosphates and deoxyadenosine triphospage that is labeled with 32P.   5′-TTTTTTTTTTTTTTT-3′ 3′-AAAAAAAAAAAAAAA-5′ Which statement best explains the radioactivity of […]