The translocation of electrically charged macromolecules through narrow channels is a fundamental process in life. The physical chemistry of this process will be narrated using simulations and polymer physics concepts against a background of single-molecule experiments. Specifically, the movement of single-stranded DNA/RNA through alpha-hemolysin channels under an external electric field will be exemplified. The implications to DNA-sequencing in biotechnology, and transport of mRNA through nuclear pores in mammalian cells will be discussed.