Chapter 3, Problem 13MIC

Why is the cell membrane not an absolute barrier between the cytoplasm and the external environment?

Which component of the plasma membrane is primarily responsible for forming a physical barrier between the cell’s internal and external environments?

Which of the following describes the plasma membrane? 1) phospholipid bilayer surrounding the cell 2) a membrane composed of tiny shelves or cristae 3) single-layered membrane that surrounds the nucleus of the cell 4) double layer of protein enclosing the plasma