A double blind study is the most rigorous clinical research design because, in addition to the randomization of subjects, which reduces the risk of bias, it can eliminate or minimize the placebo effect which is a further challenge to the validity of a study.
Transcription by RNA polymerase. An RNA strand is synthesized in the 5â²âââ3â² direction from a locally single stranded region of DNA. (After E. J. Gardner, M. J. Simmons, and D. P. Snustad, Principles of Genetics, (more...).igure 10-6. Transcription of two genes. (a) RNA polymerase moves from the 3â² end of the template strand, creating an RNA strand that grows in a 5â²âââ3â² direction (because it must be antiparallel to the template strand).
Nucleic Acid Strands Grow in the 5â² â 3â² Direction. All RNA and DNA synthesis, both cellular and viral, proceeds in the same chemical direction: from the 5â² (phosphate) end to the 3â² (hydroxyl) end (see Figure 4-13). Nucleic acid chains are assembled from 5â² triphosphates of ribonucleosides or deoxyribonucleosides.