Protein Synthesis      Section 3.5Thank you Mr. Taylor for the use of several slides
Gene Expression   RNA (ribonucleic acid)
Gene Expression   Three Classes of RNA    – Messenger RNA (mRNA)       Takes   a message from DNA to the ribosomes      ...
Gene Expression   Gene Expression Requires Two Steps:    – Transcription    – Translation
Overview: the roles of transcription and translation in the flow of genetic information                                   ...
Overview: the roles of transcription and translation in the flow of genetic information                                   ...
Overview: the roles of transcription and translation in the flow of genetic information                                   ...
Overview: the roles of transcription and translation in the flow of genetic information                                   ...
Overview: the roles of transcription and translation in the flow of genetic information                                   ...
IT’S ANN’Y TIME
Transcription
Gene Expression   Transcription    –   During transcription, a segment of the DNA        serves as a template for the pro...
Transcription of DNA to form mRNA
Translation
ANNY TIME
Gene Expression   Transfer RNA - ANTICODON    – tRNA transports amino acids to the ribosomes    – Single stranded nucleic...
Transfer RNA: Amino Acid Carrier
Gene Expression   Translation (overview)    –   In cytoplasm/ribosome    –   mRNA - Triplet codon: AUG initiates translat...
Translation
Translation
Translation
The Genetic Code
Overview of Gene Expression
Genetic Code- The Genetic Code   Triplet         code- each 3-nucleotide unit of a mRNA   molecule is called a CODON   T...
Messenger RNA Codons
Gene ExpressionDegenerate – two or more codons code for the same amino acidUniversal – all living organisms use the same c...
One Gene, One Polypeptide   1940’s (Beadle and Tatum) – one gene will always make    one enzyme.   Became – One Gene, On...
Summary of Gene Expression
END
Gene Expression   Ribosome and Ribosomal RNA    – Ribosome has a binding site for mRNA and for      2 tRNAs    – Facilita...
Polyribosome Structure and Function
mRNA Processing
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
Protein Synthesis
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Protein Synthesis

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Transcript of "Protein Synthesis"

  1. 1. Protein Synthesis Section 3.5Thank you Mr. Taylor for the use of several slides
  2. 2. Gene Expression RNA (ribonucleic acid)
  3. 3. Gene Expression Three Classes of RNA – Messenger RNA (mRNA)  Takes a message from DNA to the ribosomes  Codon  Transcription – Ribosomal RNA (rRNA)  Makes up ribosomes (along with proteins) – Transfer RNA (tRNA)  Transfers amino acids to ribosomes  Anticodon  Translation
  4. 4. Gene Expression Gene Expression Requires Two Steps: – Transcription – Translation
  5. 5. Overview: the roles of transcription and translation in the flow of genetic information (Layer 1)
  6. 6. Overview: the roles of transcription and translation in the flow of genetic information (Layer 2)
  7. 7. Overview: the roles of transcription and translation in the flow of genetic information (Layer 3)
  8. 8. Overview: the roles of transcription and translation in the flow of genetic information (Layer 4)
  9. 9. Overview: the roles of transcription and translation in the flow of genetic information (Layer 5)
  10. 10. IT’S ANN’Y TIME
  11. 11. Transcription
  12. 12. Gene Expression Transcription – During transcription, a segment of the DNA serves as a template for the production of an RNA molecule – Formation of Messenger RNA (mRNA)  RNA polymerase binds to a promoter  DNA helix is opened so complementary base pairing can occur – HELICASE!  RNA polymerase joins new RNA nucleotides in a sequence complementary to that on the DNA – Messenger RNA formed - CODON  Strand carries code for protein  Is complementary to the section of DNA
  13. 13. Transcription of DNA to form mRNA
  14. 14. Translation
  15. 15. ANNY TIME
  16. 16. Gene Expression Transfer RNA - ANTICODON – tRNA transports amino acids to the ribosomes – Single stranded nucleic acid that correlates a specific nucleotide sequence with a specific amino acid – Amino acid binds to one end, the opposite end has an anticodon – the order of mRNA codons determines the order in which tRNA brings in amino acids
  17. 17. Transfer RNA: Amino Acid Carrier
  18. 18. Gene Expression Translation (overview) – In cytoplasm/ribosome – mRNA - Triplet codon: AUG initiates translation – tRNA – attached to certain amino acids – corresponds to anticodon --- complementary to codon – mRNA bonds to tRNA – H bonds – 20 different enzymes for each amino acid – Needs ATP – 2 amino acids make peptide bond – continues – Stop codon: UAA, UAG, UGA – nonsense codon – mRNA fragment – returns to nucleus
  19. 19. Translation
  20. 20. Translation
  21. 21. Translation
  22. 22. The Genetic Code
  23. 23. Overview of Gene Expression
  24. 24. Genetic Code- The Genetic Code  Triplet code- each 3-nucleotide unit of a mRNA molecule is called a CODON  There are 64 different mRNA codons – 61 code for particular amino acids  Redundant code-some amino acids have numerous code words  Provides some protection against mutations – 1 start codon – AUG – also codes for a.a. - MET – 3 are stop codons signal polypeptide termination
  25. 25. Messenger RNA Codons
  26. 26. Gene ExpressionDegenerate – two or more codons code for the same amino acidUniversal – all living organisms use the same code (including viruses)(Transcribe and Translate a Gene)
  27. 27. One Gene, One Polypeptide 1940’s (Beadle and Tatum) – one gene will always make one enzyme. Became – One Gene, One Polypeptide Hypothesis Really One Allele, One Protein – Exceptions  Some genes do not produce polypeptides  Some genes code for RNA which does not produce a polypeptide. - (no start codon)
  28. 28. Summary of Gene Expression
  29. 29. END
  30. 30. Gene Expression Ribosome and Ribosomal RNA – Ribosome has a binding site for mRNA and for 2 tRNAs – Facilitate complementary base pairing – Ribosome moves along mRNA and new tRNAs come in and line up in order – This brings amino acids in line in a specific order to form a polypeptide – Several ribosomes may move along the same mRNA  Multiplecopies of a polypeptide may be made  The entire complex is called a polyribosome
  31. 31. Polyribosome Structure and Function
  32. 32. mRNA Processing

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