[Campbell Biology P.266] Which of the following statements about G protein-coupled receptors... | Practice Question

Which of the following statements about G protein-coupled receptors GPCRs is NOT supported by the provided text?

  • A: They constitute the largest family of human cell-surface receptors.
  • B: There are more than 800 different types of GPCRs.
  • C: Their structures are easily determined by X-ray crystallography due to their inherent stability.
  • D: Malfunctions of GPCRs are associated with various human diseases, including cancer and asthma.

Explanation

The text clearly states that determining the structures of cell-surface receptors, including GPCRs, by X-ray crystallography 'has proved challenging' because they 'tend to be flexible and inherently unstable', making option C incorrect. The other statements are directly supported by the text.