Final answer:
Most membranes used in blotting procedures, such as Southern and Northern blots, are made of positively charged nitrocellulose or nylon, which bind with negatively charged nucleic acids. These techniques involve transferring DNA or RNA onto the membranes and probing with labeled sequences to detect specific nucleic acid sequences.
Step-by-step explanation:
In blotting procedures typically used in molecular biology to detect nucleic acids (DNA or RNA), the membranes that bind to nucleic acids are usually composed of nitrocellulose or nylon. These membranes carry a positive charge, which attracts the negatively charged phosphate groups of nucleic acids, facilitating their binding during the transfer process in Southern and Northern blotting techniques developed for DNA and RNA detection, respectively. In the Southern blot technique, after agarose gel electrophoresis, DNA fragments are transferred to the membrane by capillary action and then are targeted with a labeled probe to visualize the sequence of interest. The identification is made possible by the probe that is labeled with a fluorescent dye or a radioactive molecule. Conversely, the Northern blot is used for RNA detection, with a similar methodology.