What Is the Role of Cis- Acting and Trans- Acting

question 12

Essay

What is the role of cis- acting and trans- acting factors in transcription? Explain how these factors play a role in the lac operon, and discuss how complementation can be used to identify where the mutations have occurred (structural genes versus regulatory regions). Which type of mutations can be complemented by a second gene with normal function? Are IS and OC mutants cis- or trans- acting?

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Definitions:

Myelin Sheaths

Protective covering made of fat and protein that surrounds nerve fibers, facilitating the rapid transmission of nerve impulses.

Myelin Sheath

A fatty layer that covers and insulates nerve fibers to enhance the speed of electrical impulses.

Nodes of Ranvier

Gaps in the myelin sheath of a nerve fiber where the axon is exposed, allowing for the rapid transmission of nerve impulses through saltatory conduction.

Internodes

Sections of a plant stem between two nodes, where leaves and branches are attached.