1) Suppose that a rare DNA replication error results in the duplication of a single gene, giving the daughter cell two copies of the same gene.
True or False: Gene duplication favors the acquisition of new functions by the daughter cell.
2) After several rounds of cell division, you sequence both genes and find that there are nucleotide substitutions in the second copy.
True or False: You can assume that the protein products from the two genes will have different amino acid sequences.
3) A common technique in biochemistry is to mutate a gene of interest to alter the primary sequence of the protein you are interested in studying, for instance, to replace a lysine (K) at position 2 with an alanine (A) (denoted in single letter code as K2A). Put the following proposed point mutations in order from most conservative change to the least conservative change, and explain your reasoning: K2A, K2R, K2M, K2D
4) Your lab mate hands you purified ACE2 extracellular domain, and asks you to determine the concentration. You measure the absorbance of the sample at 280 nm and get an absorbance of 0.8. Use Beer-Lambert’s law: A=ecl to determine the concentration of your labmate’s ACE2 sample. Assume the pathlength of your cuvette is 1 cm, and your buffer includes dithiothreitol. The molar extinction coefficient is 163180 M-1 cm-1. Give your answer in micromolar (uM).
Explain why you would measure the absorbance at 280 nm.