Consider the following genes in a hypothetical bacterium:
galA – encodes an enzyme that is required for cells to digest the sugar galactose
argB – encodes an enzyme that is required for cells to produce the amino acid arginineYou grow cells of this bacterium in a variety of different media. Under which conditions would you expect these genes to be expressed? Complete the table below:
Growth Medium galA Expression? argB expression?
Minimal medium with glucose as the only sugar
Minimal medium with galactose as the only sugar
Minimal medium with glucose as the only sugar and arginine
Minimal medium with galactose as the only sugar and arginine
Suppose that the galA gene was regulated by a repressor. Which of the following would be correct? Check all that apply.
The repressor for the galA gene would bind to DNA in the presence of galactose.
The repressor for the galA gene would not bind to DNA in the presence of galactose.
The repressor for the galA gene would bind to DNA in the absence of galactose.
The repressor for the galA gene would not bind to DNA in the absence of galactose.
c) You know that the argB gene is regulated, but you do not know if the regulatory protein is an activator or a repressor. You find a mutant strain of this bacterium where the gene encoding the regulatory protein has been deleted, so no regulatory protein is expressed. This strain produces the argB protein in the presence of arginine. Which of the following statements is correct?
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