Which of the following represents the order that molecules cross a synthetic membrane composed of phospholipids but not proteins, from most easily (freely permeable) to least easily (not permeable)? A)O₂, sodium ions (Na⁺), water (H₂O), glucose B)O₂, water (H₂O), glucose, sodium ions (Na⁺) C)sodium ions (Na⁺), glucose, water (H₂O), O₂ D)water (H₂O), glucose, sodium ions (Na⁺), O₂ E)glucose, water (H₂O), O₂, sodium ions (Na⁺)

Question

Quizplus · Accepted Answer

Small, nonpolar molecules like O2 cross phospholipid membranes most easily, followed by small, uncharged polar molecules like water. Larger, uncharged polar molecules like glucose cross less easily, and ions like Na+ are generally not permeable without specific transport proteins.

Which of the Following Represents the Order That Molecules Cross