You hang a microscope slide from a submerged, l-shaped pvc pipe in lake water that is 2 feet deep. the slide hangs 6 inches below the surface of the water and remains there for eight weeks. when you remove it and bring it to your lab for observation, you see that algae, bacteria, and even some fungi have colonized the slide. you determine that you are looking at a(n)

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.