[Campbell Biology P.271] According to the text, which of the following best describes the ge... | Practice Question

According to the text, which of the following best describes the general principle of signal relay in a signaling pathway?

  • A: The original signaling molecule is physically passed from one protein to the next along the pathway.
  • B: Information from the signal is transduced into a different form, often involving a shape change in the next protein.
  • C: The signal strength is amplified by increasing the concentration of the original signaling molecule at each step.
  • D: Only enzymes are involved in relaying signals, as they directly alter the chemical composition of the signaling molecule.

Explanation

The first paragraph states: 'Keep in mind that the original signaling molecule is not physically passed along a signaling pathway; in most cases, it never even enters the cell. When we say that the signal is relayed along a pathway, we mean that certain information is passed on. At each step, the signal is transduced into a different form, commonly a shape change in the next protein. Very often, the shape change is brought about by phosphorylation.' This directly describes option B.