Fig 12-1 Figure: 12-01 Caption: Flow of genetic information encoded in DNA to messenger RNA to protein.

Fig 12-2 Figure: 12-02 Caption: The effect of frameshift mutations on a DNA sequence repeating the triplet sequence GAG. (a) The insertion of a single nucleotide shifts all subsequent triplet reading frames. (b) The insertion of three nucleotides changes only two triplets, but the frame of reading is then reestablished to the original sequence.

Fig 12-3 Figure: 12-03 Caption: The reaction catalyzed by the enzyme polynucleotide phosphorylase. Note that the equilibrium of the reaction favors the degradation of RNA, but can be “forced” in the direction favoring synthesis.

Fig 12-4 Figure: 12-04 Caption: Results and interpretation of a mixed copolymer experiment in which a ratio of 1A:5C is used (1/6A:5/6C).

Fig 12-5 Figure: 12-05 Caption: An example of the triplet-binding assay. The UUU triplet acts as a codon, attracting the complementary tRNAPhe anticodon AAA.

Fig 12-6 Figure: 12-06 Caption: The conversion of di-, tri-, and tetranucleotides into repeating copolymers. The triplet codons produced in each case are shown.

Fig 12-7

Tab 12-4 Figure: 12-15-01T04 Caption: Anticodon-Codon base pairing rules

Fig 12-8 Figure: 12-08 Caption: Illustration of the concept of overlapping genes. (a) An mRNA sequence initiated at two different AUG positions out of frame with one another will give rise to two distinct amino acid sequences. (b) The relative positions of the sequences encoding seven polypeptides of the phage f x 174.

Fig 12-9 Figure: 12-09_a Caption: The early stages of transcription in prokaryotes, showing (a) the components of the process

Fig 12-9 Figure: 12-09_b Caption: The early stages of transcription in prokaryotes, showing (b) template binding at the 210 site involving the sigma subunit of RNA polymerase and subsequent initiation of RNA synthesis

Fig 12-9 Figure: 12-09_c Caption: The early stages of transcription in prokaryotes, showing (c) chain elongation, after the sigma subunit has dissociated from the transcription complex and the enzyme moves along the DNA template.

Fig 12-10 Figure: 12-10_a Caption: Posttranscriptional RNA processing in eukaryotes. Heterogeneous nuclear RNA (hnRNA) is converted to messenger (mRNA), which contains a 59 cap and a 39-poly-A tail, which then has introns spliced out.

Fig 12-10 Figure: 12-10_b Caption: Posttranscriptional RNA processing in eukaryotes. Heterogeneous nuclear RNA (hnRNA) is converted to messenger (mRNA), which contains a 59 cap and a 39-poly-A tail, which then has introns spliced out.

Fig 12-11 Figure: 12-11b Caption: An electron micrograph and an interpretive drawing of the hybrid molecule (heteroduplex) formed between the template DNA strand of the chicken ovalbumin gene and the mature ovalbumin mRNA. Seven DNA introns, A–G, produce unpaired loops.

Fig 12-12 Figure: 12-12 Caption: Intervening sequences in various eukaryotic genes. The numbers indicate the number of nucleotides present in various intron and exon regions.