Figure: 13-01 Title: How Genetic Information Produces Protein Caption: Flow chart illustrating how genetic information encoded in DNA produces protein.

Figure: 13-02 Title: Frameshift Mutations Caption: The effect of frameshift mutations on a DNA sequence with the repeating 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.

Figure: 13-03 Title: Polynucleotide Phosphorylase 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.

Figure: 13-04 Title: A Mixed Copolymer Experiment Caption: Results and interpretation of a mixed copolymer experiment where a ratio of 1A:5C is used (1/6A:5/6C).

Figure: 13-05 Title: Triplet Binding Assay Caption: An example of the triplet binding assay. The UUU triplet acts as a codon, attracting the complementary tRNAphe anticodon AAA.

Figure: 13-06 Title: The Conversion of di-, tri-, and Tetranucleotides into Repeating Copolymers Caption: The conversion of di-, tri-, and tetranucleotides into repeating copolymers. The triplet codons that are produced in each case are shown.

Figure: 13-07 Title: Triplet Coding Dictionary Caption: The coding dictionary. AUG encodes methionine, which initiates most polypeptide chains. All other amino acids except tryptophan, which is encoded only by UGG, are represented by two to six triplets. The triplets UAA, UAG, and UGA are termination signals and do not encode any amino acids.

Figure: 13-08a Title: The Early Stages of Transcription in Prokaryotes Caption: The early stages of transcription in prokaryotes, showing the components of the process.

Figure: 13-08b Title: The Early Stages of Transcription in Prokaryotes Caption: The early stages of transcription in prokaryotes, showing template binding at the -10 site involving the sigma subunit of RNA polymerase and subsequent initiation of RNA synthesis.

Figure: 13-08c Title: The Early Stages of Transcription in Prokaryotes Caption: The early stages of transcription in prokaryotes, showing chain elongation, after the sigma subunit has dissociated from the transcription complex and the enzyme moves along the DNA template.

Figure: 13-09a Title: Posttranscriptional RNA Processing in Eukaryotes Caption: Posttranscriptional RNA processing in eukaryotes. Heterogeneous nuclear RNA (pre-mRNA) is converted to mRNA, which contains a 5’-cap and a 3’-poly-A tail. The introns are then spliced out.

Figure: 13-09b Title: Posttranscriptional RNA Processing in Eukaryotes Caption: Posttranscriptional RNA processing in eukaryotes. Heterogeneous nuclear RNA (pre-mRNA) is converted to mRNA, which contains a 5’-cap and a 3’-poly-A tail. The introns are then spliced out.

Figure: 13-10b Title: Heteroduplex Molecule Caption: 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, labeled A through G, produce unpaired loops.

Figure: 13-11 Title: Intervening Sequences in Various Eukaryotic Genes Caption: Intervening sequences in various eukaryotic genes. The numbers indicate the number of nucleotides present in various intron and exon regions.

Figure: 13-12a Title: Splicing Mechanism of Pre-rRNA Caption: Splicing mechanism of pre-rRNA involving group I introns that are removed from the initial transcript. The process is one of self-excision involving two transesterification reactions.

Figure: 13-12b Title: Splicing Mechanism of Pre-rRNA Caption: Splicing mechanism of pre-rRNA involving group I introns that are removed from the initial transcript. The process is one of self-excision involving two transesterification reactions.

Figure: 13-13a Title: A Model of the Splicing Mechanism Caption: A model of the splicing mechanism involved with the removal of an intron from a pre-mRNA. Excision is dependent on various snRNAs (U1, U2,..., U6) that combine with proteins to form snurps, which are part of the spliceosome. The lariat structure in the intermediate stage is characteristic of this mechanism.

Figure: 13-13b Title: A Model of the Splicing Mechanism Caption: A model of the splicing mechanism involved with the removal of an intron from a pre-mRNA. Excision is dependent on various snRNAs (U1, U2,..., U6) that combine with proteins to form snurps, which are part of the spliceosome. The lariat structure in the intermediate stage is characteristic of this mechanism.

Figure: 13-UN01 Title: Problems and Discussion Caption: Question 10: In studies of the amino acid sequence of wild-type and mutant forms of tryptophan synthetase in E. coli, the following changes have been observed: Determine a set of triplet codes in which only a single nucleotide change produces each amino acid change.

Figure: 13-T01 Title: Table 13-1 Caption: Incorporation of 14C-Phenylalanine into Protein

Figure: 13-T02 Title: Table 13-2 Caption: Amino Acid Assignments to Specific Trinucleotides Derived from the Triplet Binding Assay

Figure: 13-T03 Title: Table 13-3 Caption: Amino Acids Incorporated Using Repeated Synthetic Copolymers of RNA

Figure: 13-T04 Title: Table 13-4 Caption: Codon-Anticodon Base-Pairing Rules

Figure: 13-T05 Title: Table 13-5 Caption: Exceptions to the Universal Code

Figure: 13-T06 Title: Table 13-6 Caption: RNA Polymerases in Eukaryotes

Figure: 13-T07 Title: Table 13-7 Caption: Comparing Human Gene Size, mRNA Size, and the Number of Introns