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The expression of Gene A is up-regulated (increased) by the activator B, which b

ID: 255928 • Letter: T

Question

The expression of Gene A is up-regulated (increased) by the activator B, which binds to the enhancer C upstream (before) of Gene A. Activator B is also activated by the effector hormone D. Once the activator B is bound by the effector D, it binds to the enhancer and recruits RNA polymerase, which binds to the promoter of gene A.

RNA activator enL Ar Question 5a: The expression of Gene A is up-regulated (increased) by the activator B, which binds to the enhancer C upstream (before) of Gene A. Activator B is also activated by the effector hormone D. Once the activator B is bound by the effector D, it binds to the enhancer and recruits RNA polymerase, which binds to the promoter of gene A How many mutations are possible for B that would prevent the gene from turning on?

Explanation / Answer

3 mutation are possible in activator B that would prevent the gene from turning on. One mutation can inhibit the binding of B to effector thus thus preventing its activation. Another mutation in B will stop its binding to enhancer and final mutation will inhibit its binding to RNA polymerase thus stopping the recruitment of RNA polymerase at the promoter region.