Transcription and Translation

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Transcription and Translation

• Getting Genetic Information
• out of DNA

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I. Transcription (DNA ? RNA)

• A. Background
• 1. DNA codes for protein production
• a. cannot leave nucleus
• b. must send out a messenger
• B. RNA the chemical messenger
• 1. differences from DNA
• a. single stranded
• b. ribose sugar
• c. Uracil (U) instead of (T)

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I. Transcription (DNA ? RNA)

• B. RNA the chemical messenger
• 2. RNAs Role...
• a. get DNA code to ribosome for protein
  synthesis
• 3. Types of RNA
• a. Messenger RNA (mRNA)
• 1. RNA copy of DNA code
• 2. takes copy to ribosome

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I. Transcription (DNA ? RNA)

• B. RNA the chemical messenger
• 3. Types of RNA
• b. Transfer RNA (tRNA)
• 1. transfers amino acids (protein
  building blocks) to protein construction
  site (ribosome)

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I. Transcription (DNA ? RNA)

• B. RNA the chemical messenger
• 3. Types of RNA
• c. Ribosomal RNA (rRNA)
• 1. structural RNA component of
  ribosomes
• 2. Ribosomes
• rRNA and Protein

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I. Transcription (DNA ? RNA)

• B. RNA the chemical messenger
• DNA RNA
• A U
• C G
• T A
• G C

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I. Transcription (DNA ? RNA)

• C. Process of Transcription
• 1. Enzymes unzip DNA (just like in
  replication)
• 2. RNA nucleotides bind to the exposed DNA
  nucleotides
• a. AGC TAA CCG ? (DNA)
• UCG AUU GGC ? (RNA)
• 3. RNA strand breaks free, leaves nucleus,
  heads to ribosome

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II. Translation (RNA ? Protein)

• mRNA is translated into polypeptide (protein)
• amino acids are joined together by peptide bonds
• polypeptide continues growing until a stop
  codon is reached

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II. Translation (RNA ? Protein)

• A. Translating the Message
• 1. every 3 letters in RNA codes for ONE
  amino acid
• a. 3 letters codon
• 2. every tRNA molecule is carrying ONE amino
  acid
• a. 3 exposed bases at the bottom are called
  anticodons

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II. Translation (RNA ? Protein)

• B. Steps in Translation
• 1. mRNA binds to the ribosome
• 2. tRNA brings amino acid to ribosome
• 3. exposed mRNA codon attracts complementary
  tRNA anticodon
• 4. mRNA and tRNA join, ribosome holds both
  in place

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II. Translation (RNA ? Protein)

• B. Steps in Translation
• 5. ribosome slides down to next codon
• 6. the next tRNA joins, ribosome creates a
  peptide bond between the two amino acids of the
  2 adjacent tRNA molecules.
• polypeptide (protein) continues growing until a
  stop codon is reached