1. FIGURE 3.1. Membranes comprise a lipid bilayer plus integral and peripheral proteins.

2. FIGURE 3.2. Small uncharged molecules can pass through membranes by simple diffusion, but hydrophilic solute cannot.

3. FIGURE 3.3. Gap junctions allow solute and electrical current to pass from the cytosol of one cell to the cytosol of its neighbor.

4. FIGURE 3. 4. Not all connexins are compatible
FIGURE 3.4. Not all connexins are compatible. A √ indicates a working gap junction, x indicates that gap junction channels cannot form.

5. FIGURE 3.5. The nucleus and the relationship of its membranes to those of the endoplasmic reticulum.

6. FIGURE 3.6. The mitochondrion.