In which concept is there a master molecule that directs all cellular activities, and its inactivation results in cellular death?

In which concept is there a master molecule that directs all cellular activities, and its inactivation results in cellular death?

• A. Indirect effect
• B. Direct effect
• C. Mutations
• D. Target theory

Answer: (D)

The idea being tested is that cells operate under the control of a specific molecular target, which serves as the central control point for cellular activities. In target theory, a drug or agent acts by binding to a defined target—often a receptor, enzyme, or other essential biomolecule—that directs how the cell functions. When that target is inactivated, the cell can no longer carry out its critical processes, which can lead to cellular dysfunction and death. This concept captures why a single, key molecule can govern many cellular activities and why disrupting it has such a profound effect. Indirect effect implies the action goes through secondary mediators rather than hitting a defined target; a direct effect focuses on immediate action at the site without implicating a central target concept; mutations refer to genetic changes rather than the pharmacologic mechanism described here.

The idea being tested is that cells operate under the control of a specific molecular target, which serves as the central control point for cellular activities. In target theory, a drug or agent acts by binding to a defined target—often a receptor, enzyme, or other essential biomolecule—that directs how the cell functions. When that target is inactivated, the cell can no longer carry out its critical processes, which can lead to cellular dysfunction and death. This concept captures why a single, key molecule can govern many cellular activities and why disrupting it has such a profound effect. Indirect effect implies the action goes through secondary mediators rather than hitting a defined target; a direct effect focuses on immediate action at the site without implicating a central target concept; mutations refer to genetic changes rather than the pharmacologic mechanism described here.