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Senanu's Bio class

Transcription activity

For this activity, we will be using the “3-D Molecular Designs Flow of Genetic Information Kit”.

In your kit, please find the following items (put the rest back in the box)

  • Transcription of DNA into RNA placemat
  • Sequence I Replication & Transcription DNA strip
  • 4 bags of DNA nucleotides (yellow = Thymine, green = Guanine, red = Adenine, blue = Cytosine)
  • 4 bags of RNA nucleotides (these have a square shape; the colors are the same as for DNA except Uracil is white).
  1. Begin by fully assembling the double-stranded DNA sequence as it is shown on the paper strip.
    1. Notice the 3’ and 5’ directionality of the DNA
    2. Notice that one molecule (strand) is the reverse complement of the other. They are not identical.
    3. Which is the 3’ end and which is the 5’ end of each nucleotide?
  2. Place your assembled DNA on the right of the placemat. Slide it toward the left.
  3. The RNA polymerase will separate the two strands of DNA.
    1. The top strand will be the template strand. It serves as a template for creating the mRNA.
    2. The bottom strand will be the non-template strand. It serves no purpose in transcription.
    3. The bottom strand is also called the “coding” strand because it has the same code as the mRNA.
  4. Push your DNA through the RNA polymerase so that about 8 nucleotides have been separated from the other strand.
  5. At the active site shown, add an RNA nucleotide (they are relatively square) that is complementary to the DNA nucleotide that is in the active site.
  6. Push the DNA sequence one base further in.
  7. Add another RNA nucleotide that is complementary to the DNA. Connect this second RNA nucleotide to the first.
  8. Continue to push the DNA further into the polymerase and adding mRNA nucleotides to the growing mRNA strand. Notice that, as with DNA, RNA is synthesized at the 3’ end.
  9. As the DNA exits from the polymerase, re-join the hydrogen bonds to re-create the double helix of DNA.
  10. The mRNA that has been growing will remain single-stranded.