Permeability coefficients measure the speed of passage of various molecules across lipid bilayers. Small nonpolar molecules and gases have higher permeability coefficient values. Charged ions have the lowest permeability coefficients. The image shows the permeability coefficient values (shown on the right) for water; glycerol (a small uncharged polar molecule); and the ions Na+, K+ and Cl–.

An up arrow titled permeability coefficients. The arrow has measurements from 10 to the negative fourteenth power at the bottom to 10 to the negative second power at the top. Upper N a +, Upper K + is at 10 to the negative twelfth power, Upper C l negative is at about 10 to the negative tenth power, glycerol is at 10 to the negative sixth power, and Upper H 2 Upper O is at about 10 to the negative third power.

Based on the info, which of the following are the correct permeability ranges for the gas O2 and the large hydrophobic amino acid tryptophan?

A. O2 will be less permeable than glycerol ( 10–2).
B. O2 will be less permeable than charged ions ( 10–2).
C. O2 will be more permeable than charged ions (>10–10). Tryptophan will be less permeable than glycerol (10–10 – 10–14).
D. O2 will be more permeable than water (>10–2). Tryptophan will be less permeable than glycerol (10–6 – 10–10).