T+T Blurt

Transcription

• DNA helicase breaks the hydrogen bonds in DNA, unwinding the double helix

• one strand acts as a template

• free RNA nucleotides are attracted to the exposes DNA bases by complementary base pairing

• adenine with uracil, cytosine with guanine

• RNA polymerase forms phosphodiester bonds between adjacent nucleotides in a condensation reaction

• a single stranded pre-mRNA is formed

• the pre mRNA is spliced by a splicesosome to remove introns

• the single stranded mRNA molecule is formed

Translation

• mRNA leaves the nucleus via nuclear pore and ribosome attaches at start codon (ribosome covers 2 codons)

• tRNA has the anticodon that is complementary to the codon on the mRNA

• tRNA has an amino acid specific to the anticodon that is joined to the molecule using energy from ATP

• anticodon on tRNA binds to codon on mRNA by complementary base pairing

• two tRNA molecules can attach to ribosome at once - ribosome forms a peptide bond between the two amino acids in a condensation reaction

• using energy from ATP

• ribosome moves along mRNA until the stop codon is reached