Answer: Both phospholipid layers completely.
- A Only the outer leaflet
- B Only the inner leaflet
- C Both phospholipid layers completely
- D Between the cell wall and membrane
Correct answer: C. Both phospholipid layers completely
Explanation: Integral (transmembrane) proteins span the entire phospholipid bilayer, with portions exposed on both sides.
Animal cell structure with major organelles labeled. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Cell theory, prokaryotic vs eukaryotic cells, organelles and their functions. Foundation of all biology.