Transcription and translation stages

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  • Created by: Hannah
  • Created on: 26-02-16 14:54
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1. Hydrogen bonds between two DNA strands in a gene break, separating the strands and
the DNA molecule uncoils at that point.
2. One of the strands is used as a template to make a RNA copy, called mRNA . The template
strand is called the antisense strand.
3. Free RNA mononucleotides line up alongside the template strand, once the RNA
mononucleotides have paired up with their complementary bases on the DNA strand
they're joined together, forming a mRNA molecule.
4. The mRNA moves out of the nucleus through a nuclear pore, and attaches to a ribosome
in the cytoplasm, where the next stage of protein synthesis takes place.
5. When enough mRNA has been produced, the hydrogen bonds between the uncoiled
strands of DNA reform, and the strand coil back into a double helix .
1. The mRNA attaches to a ribosome and transfer RNA (tRNA) molecules carry amino acids
to the ribosome.
2. A tRNA molecule, with complementary bases to the first triplet of bases (codon) on the
mRNA, attaches itself to the mRNA by complementary base pairing .
3. A second tRNA molecule attaches itself to the next triplet of bases on the mRNA in the
same way .
4. The two amino acids attached to the tRNA molecules are joined together by a peptide
bond. The first tRNA molecule moves away , leaving its amino acid behind.


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