What selective pressures are likely to have led to the evolution of regulatory systems like operons? Why not simply express these genes continuously?
What will be an ideal response?
Continual production of unnecessary enzymes is energetically costly; presumably, this is the main selective pressure to evolve regulatory mechanisms that express genes only when needed.
You might also like to view...
You’ve heard the phrase, “Feed a cold, starve a fever,” your whole life, and you’ve always considered it dubious advice at best; after all, how are you supposed to recover from any infection if you’re undernourished? After reading this module, however, you realize that one of your organs may be following a portion of this folk remedy despite your opinion. Which statement is true?
a. In response to a cold, the capillaries surrounding the stomach constrict, reducing hunger. b. In response to a cold, the pancreas produces less insulin, causing blood sugar levels to spike immediately c. In response to a fever, the liver stops releasing iron into the blood, starving certain bacteria. d. In response to a fever, the small intestine becomes more permeable to large protein molecules.
The first life on Earth was probably most similar to modern-day
A. bacteria. B. protists. C. Archaeans. D. plants. E. fungi.
The movement of the organic products of photosynthesis from the leaf to the roots is the result of what process?
a. Cellular respiration b. Replication c. Germination d. Transcription e. Translocation
The mechanism of beta-lactam drugs causes the targeted microbial agents to be susceptible to_______.
A. cold B. radiation C. osmotic pressure D. heat