Richard J. Roberts

PubMed Central is vital for researchers and the public alike. Only through free access can everyone find out where the cutting edge of research lies. With access to the latest studies, patients and their families have a much-needed piece of the puzzle as they consider treatment options and potential outcomes.

Hard as it is to imagine, there's a move afoot in Congress to take away the public's free online access to tax-funded medical research findings. That would be bad for medical discovery, bad for patients looking for the latest research results, and another rip-off of the American taxpayer.

During normal cell metabolism, RNA is constantly being made and broken down. The purine and pyrimidine residues are reused by several salvage pathways to make more genetic material. Purine is salvaged in the form of the corresponding nucleotide, whereas pyrimidine is salvaged as the nucleoside.

What do cells do when they see a broken piece of DNA? Cells don't like such breaks. They'll do pretty much anything they can to fix things up. If a chromosome is broken, the cells will repair the break using an intact chromosome.