TLS Online TPP Program

#Question id: 4018


How does binding of the lac repressor to the lac operator block transcription initiation?

#Unit 3. Fundamental Processes
  1. lac repressor binding blocks RNA polymerase from interacting with DNA at the start site.

  2. lac repressor binding induces a DNase that cleaves the DNA at the transcription start site.

  3. lac repressor binding causes a conformational change in RNA polymerase.

  4. lac repressor binding induces a protease that degrades the sigma subunit of RNA polymerase.

More Questions
TLS Online TPP Program

#Question id: 4991

#Unit 11. Evolution and Behavior

Which of these fly organs, as they exist in current fly populations, best fits the description of an exaptation?

TLS Online TPP Program

#Question id: 4992

#Unit 11. Evolution and Behavior

The existence of the phenomenon of exaptation is most closely associated with which of the following reasons that natural selection cannot fashion perfect organisms?

TLS Online TPP Program

#Question id: 4993

#Unit 11. Evolution and Behavior

If the prokaryotic flagellum developed from assemblages of proteins that originally were not involved with cell motility but with some other function instead, then the modern prokaryotic flagellum is a(n)

TLS Online TPP Program

#Question id: 4994

#Unit 11. Evolution and Behavior

In certain motile prokaryotes, dozens of different proteins comprise the motor that powers the prokaryotic flagellum. The motor has a complicated structure, and its various proteins interact to carry out its function. Based on Darwinʹs explanation for the existence of human eyes, how would he probably have explained the existence of such motors?

TLS Online TPP Program

#Question id: 4995

#Unit 11. Evolution and Behavior

It has been found that certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This is evidence in support of the claim that

TLS Online TPP Program

#Question id: 4996

#Unit 11. Evolution and Behavior

An explanation for the evolution of insect wings suggests that wings began as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air, and selection later refined them as flight-producing wings. If this hypothesis is correct, insect wings could best be described as