Radio Stars. Quasars are the brightest and most distant objects in the known universe. In the early 1960's, quasars were referred to as radio stars because they were discovered to be a strong source of radio waves. In fact, the term quasar comes from the words, quasi-stellar radio source.
The following DNA sequence occurs in the nontemplate strand of a structural gene in bacterium (the promoter sequence is located to the left but is not shown): 5 -GAATGTCAGAACTGCCATGCTTCATATGAATAGACCTCTAG-3 What is the ribonucleotide sequence of mRNA molecule that is transcribed from this piece of DNA?
The regular pairing of bases in the double-helical DNA structure suggested to Watson and Crick a mechanism of DNA synthesis. Their proposal that new strands of DNA are synthesized by copying of parental strands of DNA has proved to be correct. The DNA strand that is copied to form a new strand is called a template. The information in the template is preserved: although the first copy has a complementary sequence, not an identical one, a copy of the copy produces the original (template) sequence again.