Bio3400 Chapter 13 The Genetic Code and Transcription
  1. The genetic code is composed of triplets of       that make up         , each of which specifies one amino acid.

  2. The triplet nature of the code was first revealed by             mutations.

    • The genetic code was first cracked by using artificial RNA               in an           translation system to synthesize polypeptides.

    • Next, RNA                 were used to discover the base composition of more codons.

    • Then, the          binding assay was used to determine other specific codon assignments.

    • Finally, repeating             were used to complete the construction of the genetic code.

  3. The genetic code is             , and exhibits         pairing at the third codon position.

  4. The genetic code is nearly universal, with minor             such as those found in mitochondrial DNA.

  5. In some viruses, different initiation points lead to              genes.

  6. Studies with bacteriophage infection provided initial evidence that      serves as the intermediate molecule between DNA and proteins.

  7. Transcription begins with template binding by      polymerase at an site upstream to the gene called the           .

  8. Eukaryotes possess three forms of      polymerase, each of which transcribes different types of genes.

  9. The initial transcript in eukaryotes is a           that must be processed by splicing together the        to produce the mature mRNA.

  10. Introns are removed by splicing together the        by            ( group I and II) or by               (group III ).

  11. The size of the mature       is usually much smaller than that of the initial RNA transcript.

  12. Transcription can now be visualized using electron microscopy.