[Campbell Biology P.441] Based on the diagram "Normal Breast Cells in a Milk Duct", which of... | Practice Question

Based on the diagram "Normal Breast Cells in a Milk Duct", which of the following statements about the cellular location of the discussed receptors is correct?

  • A: Estrogen receptor alpha (ERα) and Progesterone receptor (PR) are shown as transmembrane proteins on the cell surface.
  • B: HER2 and HER3 are depicted as receptors embedded in the cell membrane.
  • C: All three signal receptors (ERα, PR, HER2) are found exclusively within the cell's nucleus.
  • D: HER2 and HER3 are located in the extracellular matrix, outside the cell.

Explanation

The diagram clearly illustrates HER2 and HER3 as integral membrane proteins. ERα and PR are shown inside the cell intracellular/cytoplasmic/nuclear , consistent with their description as steroid receptors, which typically bind ligands in the cytoplasm and then translocate to the nucleus.