DNA Transcription

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DNA Transcription Translation

• Bio 6B Explain replication, transcription, and
  translation using models of DNA and ribonucleic
  acid RNA

Transcription Translation DNA
mRNA Protein occurs in nucleus
occurs on ribosome
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DNA Transcription

• The word transcribe means to copy. During
  transcription, the genetic information code is
  copied into a single strand of mRNA. mRNA is
  known as messenger RNA because it carries the
  DNA code or message out of the nucleus and into
  the cytoplasm.
• DNA cannot travel out of the nucleus but RNA can.
• RNA contains the base Uracil instead of Thymine.

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Transcription Activity

• Transcribe the DNA strand on your handout into a
  strand of mRNA.
• REMEMBER Uracil is in a RNA strand instead of
  Thymine.
• Example
• DNA TACACGATT
• mRNA AUGUGCUAA

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Translation

• In order for translation to begin, mRNA must
  first attach itself to a ribosome which is found
  in the cytoplasm of a cell. The information in
  mRNA is organized into three-letter blocks called
  codons. Codons are like words of the RNA message.

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Codon Activity

• Organize your mRNA into three letter blocks
  called codons.
• Example
• mRNA AUGUGCUAAG
• AUG UGC UAC

Three letter blocks codons
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Codons

• Each codon codes for a specific amino acid in the
  protein chain. tRNA (transfer) matches a
  particular codon to a particular amino acid.
  Amino acids are joined together in the correct
  sequence to form a protein chain.

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How do I read a Codon chart?

• First letter represents the first letter of a
  codon. Example AUG
• Second letter represents the second letter of a
  codon. Example AUG
• Third letter represents the third letter of a
  codon. Example AUG
• The amino acid coded for the codon AUG is
  methionine.

Its your turn to practice using the codon chart!
Identify the amino acids represented by the
codons on your handout.
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Codon chart activity

• Use your codon chart to identify the amino acids
  coded in your mRNA strand.