Gene Expression and Regulation

Eight topics tracing the flow of genetic information from DNA to trait. The structure of DNA and RNA and why the two are not interchangeable, replication that is semiconservative — each new helix keeps one old strand — with leading and lagging strands built differently, transcription and RNA processing that make and edit a messenger rather than a protein, translation where the ribosome reads mRNA codons and tRNA anticodons to build a protein, the regulation of gene expression that switches genes on and off without changing the DNA, gene expression and cell specialization where every cell keeps the same genome but expresses it differently to become a specialized type, mutations that range from silent to harmful to beneficial, and the biotechnology tools — PCR, gel electrophoresis, restriction enzymes, and CRISPR — used to copy, cut, sort, and edit DNA.