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www.psmag.com 
FROM DNA TO PROTEINS 
PART 3
michaelgray.org.uk
GENERAL PATHWAY 
PROKARYOTES vs EUKARYOTES 
employees.csbsju.edu
Prokaryotes vs Eukaryotes 
Prokaryote Eukaryote 
Site of DNA Replication Protoplasm Nucleus 
Site of Transcription Protopl...
michaelgray.org.uk 
GENERAL STEPS IN DNA REPLICATION
DNA REPLICATION 
SEMI-CONSERVATIVE
STEPS 
Unwinding & Strand Separation 
Helicase will unwind the parental strands 
breaks the H-bonds between bases 
SSBP (S...
STEPS
Unwinding & STEPS 
Strand 
Separation 
Topoisomerase 
breaks and 
rejoins the DNA 
double helix to 
relieve 
twisting 
for...
STEPS 
Priming 
Primase catalyzes synthesis of RNA primers 
RNA primers attach to specific site of DNA 
strand (ORI region...
STEPS
STEPS 
Synthesis of New Strands 
Lagging strand (Discontinuous): DNA 
polymerase III extends the Okazaki fragments 
DNA po...
STEPS
pulpbits.com 
DNA REPLICATION: Prokaryotes
DNA REPLICATION: Eukaryotes 
For VIDEOS: https://www.youtube.com/ 
watch?v=27TxKoFU2Nw
ENZYMES INVOLVED IN DNA REPLICATION 
http://sydney.edu.au
TELOMERASE AND GENE 
EROSION 
TELOMERES: ends of the DNA 
each chromosome is one continuous double stranded 
length of DNA...
TELOMERASE AND GENE EROSION
TELOMERASE AND GENE EROSION
QUESTIONS????
REVERSE TRANSCRIPTION
REVERSE TRANSCRIPTION
OVERVIEW OF 
TRANSCRIPTION 
& TRANSLATION
TRANSCRIPTION 
Process of copying DNA to RNA 
NOTE: only one strand of DNA, the template strand, 
is used to make mRNA 
Do...
STEPS IN TRANSCRIPTION
STEPS IN TRANSCRIPTION
RNA POLYMERASE 
RNA polymerase only transcribes one strand of 
the parental DNA molecule (the template strand) 
in the 3' ...
RECALL…
INTRONS AND EXONS 
Introns 
sequences in the DNA that are NOT used to 
make mRNA or to make a protein 
they are NOT transc...
POST-TRANSCRIPTIONAL 
MODIFICATION IN EUKARYOTES 
RNA SPLICING 
REMOVAL OF INTRONS 
5’ METHYLATED CAP AND POLYADENYLATION ...
FINAL PRODUCT AFTER 
TRANSCRIPTION
www.can-con.ca 
TRANSLATION CAN BEGIN…
CONTROL DURING 
TRANSCRIPTION 
PROKARYOTES 
regulating genetic expression in nearby genes 
(e.g. LAC OPERON) 
EUKARYOTES 
...
the LAC OPERON
TRANSLATION: 
FROM VAGUE DNA CODES TO 
MEANINGFUL TRAITS 
blog.lionbridge.com
THE ASSEMBLY 
barleyworld.org
blog.lionbridge.com
blog.lionbridge.com
blog.lionbridge.com
blog.lionbridge.com
blog.lionbridge.com
For VIDEOS: https://www.youtube.com/watch? 
v=5bLEDd-PSTQ
IN SUMMARY…
EXAMPLE… 
DNA 
5’-ATG GTT CGG TAG-3’ 
! 
Replicating this strand.. 
5’-CTA CCG AAC CAT-3’ 
mRNA transcript to undergo tran...
THE GENETIC CODE 
igoscience.com
THE GENETIC CODE 
www.mun.ca 
http://www.genome.jp/kegg/ 
catalog/codes1.html
NUCLEOTIDE 
CODES 
A 
Adenine 
G Guanine 
C Cytosine 
T Thymine 
U Uracil 
R Purine (A or G) 
Y Pyrimidine (C or T) 
N Any...
AMINO 
ACID CODES 
Ala A Alanine 
Arg R Arginine 
Asn N Asparagine 
Asp D Aspartic acid 
Cys C Cysteine 
Gln Q Glutamine 
...
AMINO 
ACID CODES 
Lys K Lysine 
Met M Methionine 
Phe F Phenylalanine 
Pro P Proline 
Ser S Serine 
Thr T Threonine 
Trp ...
DNA SEQUENCE
PROTEIN SEQUENCE 
www.wiley.com
LET’S TRY… 
www.wiley.com 
Met M Methionine 
His H Histidine 
Gly G Glycine 
Asn N Asparagine 
Leu L Leucine
AMINO ACID SEQUENCE 
IS… 
www.wiley.com 
Met M Methionine 
His H Histidine 
Gly G Glycine 
Asn N Asparagine 
Leu L Leucine...
NUCLEOTIDE SEQUENCE 
IS… 
www.wiley.com 
from the sequence… 
(AUA or AUG)-(CAU or 
CAC)-(GGU or GGC or 
GGA or GGG)-(AAU o...
LET’S HAVE A GROUPIE…
FORM YOUR GROUPS 
You will be given set of questions and can discuss by group 
for the FINAL answer 
The score of the grou...
QUESTIONS 
In order to properly construct a protein, which process must 
occur first: transcription or translation? Why? 
...
SEE YOU ON MONDAY FOR 
YOUR EXAM 1
Lecture on DNA to Proteins (The Central Dogma of Molecular Biology)
Lecture on DNA to Proteins (The Central Dogma of Molecular Biology)
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Lecture on DNA to Proteins (The Central Dogma of Molecular Biology)

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Lecture on DNA to Proteins (The Central Dogma of Molecular Biology)

  1. 1. www.psmag.com FROM DNA TO PROTEINS PART 3
  2. 2. michaelgray.org.uk
  3. 3. GENERAL PATHWAY PROKARYOTES vs EUKARYOTES employees.csbsju.edu
  4. 4. Prokaryotes vs Eukaryotes Prokaryote Eukaryote Site of DNA Replication Protoplasm Nucleus Site of Transcription Protoplasm Nucleus Site of RNA Splicing Rare Nucleus Site of Translation Protoplasm Cytoplasm Site of Recombination Protoplasm Nucleus
  5. 5. michaelgray.org.uk GENERAL STEPS IN DNA REPLICATION
  6. 6. DNA REPLICATION SEMI-CONSERVATIVE
  7. 7. STEPS Unwinding & Strand Separation Helicase will unwind the parental strands breaks the H-bonds between bases SSBP (Single-stranded DNA-binding proteins) attaches to separated strands and keep them from annealing back
  8. 8. STEPS
  9. 9. Unwinding & STEPS Strand Separation Topoisomerase breaks and rejoins the DNA double helix to relieve twisting forced by the opening of the helix (supercoils) mol-biol4masters.masters.grkraj.org
  10. 10. STEPS Priming Primase catalyzes synthesis of RNA primers RNA primers attach to specific site of DNA strand (ORI region) Synthesis of New Strands Leading strand (Continuous): DNA polymerase III catalyzes synthesis of new DNA strands at 5’ to 3’ direction (as single polymer) and extends the leading strand
  11. 11. STEPS
  12. 12. STEPS Synthesis of New Strands Lagging strand (Discontinuous): DNA polymerase III extends the Okazaki fragments DNA polymerase I removes RNA primers and replaces it with DNA Sealing the nick DNA Ligase forms covalent bonds from 3’ to 5’ direction to join the Okazaki fragments into a continuous strand
  13. 13. STEPS
  14. 14. pulpbits.com DNA REPLICATION: Prokaryotes
  15. 15. DNA REPLICATION: Eukaryotes For VIDEOS: https://www.youtube.com/ watch?v=27TxKoFU2Nw
  16. 16. ENZYMES INVOLVED IN DNA REPLICATION http://sydney.edu.au
  17. 17. TELOMERASE AND GENE EROSION TELOMERES: ends of the DNA each chromosome is one continuous double stranded length of DNA with 2 telomeres The 3’ to 5’ parent strand is copied no trouble as the leading strand BUT the lagging strand (parent 5’ to 3’) has small primers made every so often and filled in NOTE: no template at the end to bind to so when the primers are removed there is an overhang and exposes the DNA to digestion which would eventually eat into the genes at the end (gene erosion)
  18. 18. TELOMERASE AND GENE EROSION
  19. 19. TELOMERASE AND GENE EROSION
  20. 20. QUESTIONS????
  21. 21. REVERSE TRANSCRIPTION
  22. 22. REVERSE TRANSCRIPTION
  23. 23. OVERVIEW OF TRANSCRIPTION & TRANSLATION
  24. 24. TRANSCRIPTION Process of copying DNA to RNA NOTE: only one strand of DNA, the template strand, is used to make mRNA Does not need a primer to start and can involve multiple RNA polymerases Divided into 3 stages Initiation Elongation For VIDEOS: https:// Termination www.youtube.com/watch? v=WsofH466lqk
  25. 25. STEPS IN TRANSCRIPTION
  26. 26. STEPS IN TRANSCRIPTION
  27. 27. RNA POLYMERASE RNA polymerase only transcribes one strand of the parental DNA molecule (the template strand) in the 3' to 5' direction RNA polymerase will never add a T, instead it will add a U Transcription ceases when RNA polymerase encounters special DNA sequences termed terminators that stop the process of transcription
  28. 28. RECALL…
  29. 29. INTRONS AND EXONS Introns sequences in the DNA that are NOT used to make mRNA or to make a protein they are NOT transcribed Exons sequences in the DNA that are expressed or used to make mRNA and ultimately are used to make a protein
  30. 30. POST-TRANSCRIPTIONAL MODIFICATION IN EUKARYOTES RNA SPLICING REMOVAL OF INTRONS 5’ METHYLATED CAP AND POLYADENYLATION PREVENTS DEGRADATION DURING TRANSIT FROM NUCLEUS TO CYTOPLASM
  31. 31. FINAL PRODUCT AFTER TRANSCRIPTION
  32. 32. www.can-con.ca TRANSLATION CAN BEGIN…
  33. 33. CONTROL DURING TRANSCRIPTION PROKARYOTES regulating genetic expression in nearby genes (e.g. LAC OPERON) EUKARYOTES involves the organization of chromatin and specific transcription factors which function by either changing the rate of transcription or altering the accessibility of chromatin to transcriptional machinery
  34. 34. the LAC OPERON
  35. 35. TRANSLATION: FROM VAGUE DNA CODES TO MEANINGFUL TRAITS blog.lionbridge.com
  36. 36. THE ASSEMBLY barleyworld.org
  37. 37. blog.lionbridge.com
  38. 38. blog.lionbridge.com
  39. 39. blog.lionbridge.com
  40. 40. blog.lionbridge.com
  41. 41. blog.lionbridge.com
  42. 42. For VIDEOS: https://www.youtube.com/watch? v=5bLEDd-PSTQ
  43. 43. IN SUMMARY…
  44. 44. EXAMPLE… DNA 5’-ATG GTT CGG TAG-3’ ! Replicating this strand.. 5’-CTA CCG AAC CAT-3’ mRNA transcript to undergo translation 5’-AUG GUU CGG UAG-3’ peptide from mRNA after translation Met-Val-Arg-STOP
  45. 45. THE GENETIC CODE igoscience.com
  46. 46. THE GENETIC CODE www.mun.ca http://www.genome.jp/kegg/ catalog/codes1.html
  47. 47. NUCLEOTIDE CODES A Adenine G Guanine C Cytosine T Thymine U Uracil R Purine (A or G) Y Pyrimidine (C or T) N Any nucleotide W Weak (A or T) S Strong (G or C) M Amino (A or C) K Keto (G or T) B Not A (G or C or T) H Not G (A or C or T) D Not C (A or G or T) V Not T (A or G or C)
  48. 48. AMINO ACID CODES Ala A Alanine Arg R Arginine Asn N Asparagine Asp D Aspartic acid Cys C Cysteine Gln Q Glutamine Glu E Glutamic acid Gly G Glycine His H Histidine Ile I Isoleucine Leu L Leucine
  49. 49. AMINO ACID CODES Lys K Lysine Met M Methionine Phe F Phenylalanine Pro P Proline Ser S Serine Thr T Threonine Trp W Tryptophan Tyr Y Tyrosine Val V Valine Asx B Asn or Asp Glx Z Gln or Glu Xle J Leu or Ile Sec U Selenocysteine (UGA) Pyl O Pyrrolysine (UAG) Unk X Unknown
  50. 50. DNA SEQUENCE
  51. 51. PROTEIN SEQUENCE www.wiley.com
  52. 52. LET’S TRY… www.wiley.com Met M Methionine His H Histidine Gly G Glycine Asn N Asparagine Leu L Leucine
  53. 53. AMINO ACID SEQUENCE IS… www.wiley.com Met M Methionine His H Histidine Gly G Glycine Asn N Asparagine Leu L Leucine MHGNL met-his-gly-asn-leu
  54. 54. NUCLEOTIDE SEQUENCE IS… www.wiley.com from the sequence… (AUA or AUG)-(CAU or CAC)-(GGU or GGC or GGA or GGG)-(AAU or AAC)-(CUU or CUC or CUA or CUG) ! EXAMPLE: nucleotide sequence may be AUA-CAU-GGU-AAU-CUU ! EXAMPLE: amino acid sequence is MHGNL or met-his-gly-asn-leu
  55. 55. LET’S HAVE A GROUPIE…
  56. 56. FORM YOUR GROUPS You will be given set of questions and can discuss by group for the FINAL answer The score of the group will be the score of each individual for today’s QUIZ Submission is TOMORROW, 12noon, DB (Look for ate Malou) READY???
  57. 57. QUESTIONS In order to properly construct a protein, which process must occur first: transcription or translation? Why? LAC operon: Under what conditions is the operator activated? Under what conditions is it inactivated? Assume that the following sequence of bases represents a segment of DNA that is to undergo transcription. Determine the corresponding sequence of bases in the resulting RNA molecule. 3’-TAC GGC ATT GCA CAT TTT AGG GGC AAT ATT-5’ The following mRNA segment represents three codons. In each case determine what the anticodon would be on the appropriate tRNA. AAA CGA AAU
  58. 58. SEE YOU ON MONDAY FOR YOUR EXAM 1

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