[Campbell Biology P.178] Which of the following statements about membrane proteins, as descr... | Practice Question

Which of the following statements about membrane proteins, as described in the text, is correct?

  • A: Peripheral proteins are deeply embedded within the hydrophobic interior of the lipid bilayer, just like integral proteins.
  • B: All integral proteins span the entire membrane as transmembrane proteins.
  • C: Membrane proteins often form the main fabric of the membrane, while phospholipids determine most of its functions.
  • D: Membrane proteins can attach to the cytoskeleton on the cytoplasmic side or to the extracellular matrix on the extracellular side.

Explanation

The text explicitly states: 'On the cytoplasmic side of the plasma membrane, some membrane proteins are held in place by attachment to the cytoskeleton. And on the extracellular side, certain membrane proteins may attach to materials outside the cell. For example, in animal cells, membrane proteins may be attached to fibers of the extracellular matrix.' This directly supports option D.