You tested for the presence of four different ✔ nutrients by adding ✔ indicators to the three test tubes. If the mystery food sample contained the nutrient, then it would change to the same color as the

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.