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DNA, RNA and Protein

DNA, RNA and Protein. How the Information in DNA Is Used to Build a Protein. Replication (prior to nuclear division). transcription. translation. Information Flow From DNA. Gene: sequence of DNA that codes for a protein. DNA. (maintain cell metabolism and support growth). RNA. Protein.

allistair-emerson
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DNA, RNA and Protein

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  1. DNA, RNA and Protein How the Information in DNA Is Used to Build a Protein

  2. Replication(prior to nuclear division) transcription translation Information Flow From DNA Gene: sequence of DNA that codes for a protein DNA (maintaincell metabolismand supportgrowth) RNA Protein

  3. DNA and RNA Structure Nucleotide = phosphate + sugar + nitrogen-containing base

  4. DNA and RNA Structure OH OH OH H

  5. Nucleotide Chain Nucleotides are joined together by dehydration synthesis The phosphate of one nucleotide is joined to sugar of next nucleotide, forming a “sugar-phosphate backbone”

  6. T G T A C T 3’ end DNA Structure A 5’ endhas free phosphate • Two nucleotide chains • In opposite orientations • Held together by hydrogen bonds • Twisted into a helix C G pairs with C A T G A 3’ endhas free sugar 5’ end A pairs with T

  7. Applying Your Knowledge In the DNA double helix, which base is paired with adenine? • Adenine • Cytosine • Guanine • Thymine • Uracil

  8. DNA Replication • DNA chains separate • Each chain is used as a pattern to produce a new chain • Each new DNA helix contains one “old” and one “new” chain

  9. DNA Replication DNA replication requires 1. Enzymes, including DNA polymerase that adds nucleotides in a 5’3’ direction. 2. nucleotides 3. energy 5’—A G C T — 3’ 3’— T C G A — 5’ 5’— A G C T— 3’ 3’—T C G A — 5’

  10. After DNA replication, what is the composition of the new double-helical molecules? Two new chains Two old chains One old and one new chain One helix has two new chains and one has two old chains None of these is correct. Applying Your Knowledge

  11. 5’ 5’ 3’ 3’ Join the phosphate of one nucleotide to the sugar of the next one Building Your DNA Model One chain can have bases in any order, the other chain must be complementary Your completed model will have two DNA chains, each with 9 nucleotides.

  12. Transcription = Production of RNA Using DNA as a Template • DNA chains separate • ONE DNA chain is used as a pattern to produce an RNA chain • RNA chain is released and the DNA chains reform the double-helix In DNA In RNAA U T A G C C G

  13. 3’---TACAAA GAGACT---5’ DNA template 5’---ATG TTTCTC TGA---3’ Transcription Transcription requires 1. Enzymes, including RNA polymerase that adds nucleotides in a 5’3’ direction. 2. nucleotides 3. energy 3’---TACAAAGAGACT---5’ 5’---ATG TTTCTC TGA---3’ 5’---AUGUUUCUCUGA---3’ mRNA

  14. Applying Your Knowledge What is the sequence of an RNA molecule transcribed from a DNA template strand that reads 3’-ATG-5’? • 5’-TAC-3’ • 5’-CAU-3’ • 5’-AUG-3’ • 5’-UAC-3’ • 3’-TAC-5’

  15. Products of Transcription • Messenger RNA Contains the code words for the sequence of amino acids in a specific protein CODON = group of three nucleotides acting as a code word for an amino acid

  16. In mRNA In tRNAA U U A G C C G mRNA Products of Transcription • Transfer RNA “Translates” the message by bringing a specific amino acid into the correct position on the growing protein chain Has ANTICODON = a group of three nucleotides on a tRNA that recognizes a mRNA codon Has amino acid attachment site

  17. Genetic Code Chart is written as a CODON dictionary, reading 5’3’

  18. for tRNA for tRNA small ribosomal subunit mRNA binding site Products of Transcription • Ribosomal RNA One of the structural components of the ribosome Ribosome = organelle where protein synthesis occurs Has sites to bind both mRNA and tRNA

  19. Applying Your Knowledge Which molecule contains the information for assembling the amino acids in the correct order in the protein? • rRNA • tRNA • mRNA • All of these • None of these

  20. 5’ 5’ 3’ 3’ Choose one DNA chain as the template for RNA Building Your DNA Model Read the template from 3’5’ to produce the mRNA from 5’3’ Your completed messenger RNA will have 9 nucleotides.

  21. Translation At the ribosome, codons in mRNA are recognized by tRNA anticodons to place amino acids in the specific sequence specified by the DNA. Three Stages of Translation: Initiation- assemble components to start process Elongation- add amino acids in repeated cycles Termination- release protein product

  22. Translation Initiation mRNA binds to ribosome First tRNA binds to mRNA met UAC 5’---AUGUUUCUCUGA---3’ mRNA

  23. Translation Elongation Next tRNA binds to mRNA met phe UAC AAA 5’---AUGUUUCUCUGA---3’ mRNA

  24. Translation Elongation Amino acids are joined First tRNA is released met phe UAC AAA 5’---AUGUUUCUCUGA---3’ mRNA

  25. Translation Elongation Ribosome moves by one codon met phe UAC AAA 5’---AUGUUUCUCUGA---3’ mRNA

  26. Translation Elongation (second cycle) Next tRNA binds to mRNA met phe leu UAC AAA GAG 5’---AUGUUUCUCUGA---3’ mRNA

  27. Translation Elongation (second cycle) Amino acids are joined Second tRNA is released met phe leu UAC GAG 5’---AUGUUUCUCUGA---3’ mRNA AAA

  28. Translation Elongation (second cycle) Ribosome moves by one codon met phe leu UAC GAG 5’---AUGUUUCUCUGA---3’ mRNA AAA

  29. Translation Termination Termination factor binds to stop codon met phe leu UAC T GAG 5’---AUGUUUCUCUGA---3’ mRNA AAA

  30. Translation Termination Protein chain is released Other components separate met phe leu UAC T GAG AAA 5’---AUGUUUCUCUGA---3’ mRNA

  31. Applying Your Knowledge If the mRNA sequence for codons 5, 6, and 7 of a protein is 5’-AAG-AUU-GGA-3’, what is the amino acid sequence in the protein? • Gly-ile-lys • Arg-leu-glu • Glu-leu-arg • Asn-met-gly • Lys-ile-gly

  32. CODON Attach 3 bases to the tRNA to form the anticodon Building Your DNA Model Read the CODON from 5’3’ to find the name of the amino acid Serine Your completed model will have 3 tRNAs, one for each codon in mRNA. Show the name of the amino acid carried by each tRNA.

  33. Summary of Completed DNA Model • One DNA double helix, two chains of 9 nucleotides each • one chain can have any sequence • second chain must be complementary • One chain of mRNA, 9 nucleotides long • must be complementary to one of the two DNA chains (DNA template is 3’5’, mRNA is 5’3’) • Three tRNAs with appropriate amino acids attached • tRNA anticodons must match mRNA codons

  34. Functions of Nucleic Acids • DNA is the genetic material • RNA is an intermediary in protein synthesis • The nucleotide ATP is an energy carrier for cell activities

  35. Energetic ~ A P P ( ) ~ P ADP ~ ~ ( ) A P P P ATP Breakdown of ATP:  Releasing Energy for Work

  36. ~ A P P ( ) ADP ~ ~ ( ) A P P P Pi ATP Synthesis of ATP: Storing Energy + energy + (Inorganic Phosphate)

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