[Campbell Biology P.275] According to the text, which of the following is an example of a cy... | Practice Question

According to the text, which of the following is an example of a cytoplasmic cellular response to a signal, rather than a nuclear response?

  • A: Synthesis of specific messenger RNAs (mRNAs).
  • B: Activation of a transcription factor that regulates gene expression.
  • C: Opening or closing of an ion channel in the plasma membrane.
  • D: Turning specific genes 'on' or 'off'.
  • E: Transcription of DNA into mRNA.

Explanation

The text states that cytoplasmic responses directly affect proteins that function outside the nucleus, giving examples such as 'opening or closing of an ion channel in the plasma membrane or a change in the activity of a metabolic enzyme'. Nuclear responses, in contrast, involve changes in gene expression, such as mRNA synthesis or turning genes on/off.