Protein Synthesis

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Protein Synthesis
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Review!

• What are some functions of proteins?
• Enzymes, which speed up chemical reactions
• Build and repair cell structures
• Determine the structure function of living
  organisms

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Review!

• Proteins are polymers, made up of monomers called
  amino acids
• There are 20 different types of amino acids

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Review!

• What codes for these proteins?
• DNA contains the sequence of nucleotides that
  codes for the synthesis of proteins.
• Problem
• DNA is found in the nucleus.
• Proteins are made at the ribosomes, which are
  found in the cytoplasm

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• HOW CAN THE INFORMATION FROM THE NUCLEUS GET TO
  THE RIBOSOME?
• RNA! mRNA is used to move information from the
  DNA to ribosomes
• This process is called TRANSCRIPTION.

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Translation

• The process of converting the information in the
  nitrogen base sequence of mRNA into a sequence of
  amino acids which make up proteins
• Occurs in the RIBOSOMES

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Translation

• 1. mRNA attaches and passes through the ribosome.
• 2. First codon on mRNA moves into position.
• 3. tRNA (transfer RNA) starts to bring amino
  acids to the ribosome.

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Translation

• 4. tRNA ANTICODON matches up to mRNA codon.
• 5. mRNA slides through the ribosome to next mRNA
  codon.

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Translation

• 6. New tRNA anticodon matches to next mRNA codon.
• 7. Amino acids on two tRNAs form a peptide bond
  with one another. First tRNA floats away to pick
  up another amino acid for later use

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Translation

• 8. Process continues until a stop codon on the
  mRNA is reached.
• 9. Result an amino acid chain is created
• Chain of amino acids polypeptide chain
  PROTEIN (more than one polypeptide chain)
• Protein Synthesis Animation

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Lets Reviewagain!
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Decode the following

• If the coding DNA strand contained the following
  sequence TAC CGA TTG ACT
• What would the mRNA strand be?
• AUG GCU AAC UGA
• What would the tRNA sequence be?
• UAC CGA UUG ACU
• What would the amino acid sequence be?
• (base it on the mRNA strand!)
• methionine, alanine, asparagine, stop