1. Nucleic Acids and Protein Synthesis

2. Nucleic Acids DNA DNA Deoxyribonucleic Acid Deoxyribonucleic Acid RNA RNA Ribonucleic Acid Ribonucleic Acid

3. DNA Double stranded helix Double stranded helix Never leaves the nucleus Never leaves the nucleus Watson, Crick, Wilkins won Nobel Prize in 1962 Watson, Crick, Wilkins won Nobel Prize in 1962 Franklin died in 1958 never recognized Franklin died in 1958 never recognized

4. DNA

5. Nucleotide Building Blocks of nucleic acids are NUCLEOTIDES! Building Blocks of nucleic acids are NUCLEOTIDES! Phospate group Phospate group Sugar molecule (deoxyribose) Sugar molecule (deoxyribose) Nitrogenous bases Nitrogenous bases

6. Nitrogenous Bases of DNA

7. How do the N-Bases pair up? A-T (2 bonds) A-T (2 bonds) G-C (3 bonds) G-C (3 bonds)

8. How Does DNA Replicate? 1. double helix unwinds 1. double helix unwinds 2. Each chain serves as a template for new nucleoide chain 2. Each chain serves as a template for new nucleoide chain 3. point at which 2 chains separate is called the REPLICATION FORK. 3. point at which 2 chains separate is called the REPLICATION FORK. 4. HELICASE = the enzyme that separates the chains (breaks H bonds) 4. HELICASE = the enzyme that separates the chains (breaks H bonds) 5. DNA POLYMERASE moves along the chains and helps assemble new nucleotides forming new chains (3’ to 5’ ONLY) 5. DNA POLYMERASE moves along the chains and helps assemble new nucleotides forming new chains (3’ to 5’ ONLY) DNA LIGASE – ligates 5’ to 3’ (DNA polymerase brings the nucleotides) DNA LIGASE – ligates 5’ to 3’ (DNA polymerase brings the nucleotides)

9. DNA replication continue… The 3’ sugar has an –OH GROUP The 3’ sugar has an –OH GROUP The 5’ sugar has a PHOSPHATE GROUP The 5’ sugar has a PHOSPHATE GROUP LEADING STRAND – formed from 3’-5’ LEADING STRAND – formed from 3’-5’ LAGGING STRAND – formed from 5’- 3’ with the help of DNA LIGASE! LAGGING STRAND – formed from 5’- 3’ with the help of DNA LIGASE! OKAZAKI FRAGMENTS – fragments that will be ligated together OKAZAKI FRAGMENTS – fragments that will be ligated together

10. Can you see how DNA is making an exact copy of itself! *

11. This a little more difficult Can you figure out the diagram? Can you figure out the diagram?

13. Simplest Illustration of DNA replication…

14. What is a mutation ?? A CHANGE in the nucleotide sequence at even ONE location!! A CHANGE in the nucleotide sequence at even ONE location!!

15. Protection About 1 in a billion nucleotides in DNA is INCORRECTLY paired. About 1 in a billion nucleotides in DNA is INCORRECTLY paired. DNA polymerase proofreads and removes nucleotides that base pair incorrectly. DNA polymerase proofreads and removes nucleotides that base pair incorrectly. DNA polymerase & DNA ligase  also repair damage caused by ultraviolet light, xrays, and toxic chemicals DNA polymerase & DNA ligase  also repair damage caused by ultraviolet light, xrays, and toxic chemicals

16. Archibald Garrod 1909 English Physician Suggested that genes dictate phenotypes through enzymes, the proteins that catalyze chemical processes in the cell Suggested that genes dictate phenotypes through enzymes, the proteins that catalyze chemical processes in the cell GENOTYPE  genetic make up GENOTYPE  genetic make up PHENOTYPE  physical appearance PHENOTYPE  physical appearance DNA –(transcription)  RNA – (translation)  protein synthesis DNA –(transcription)  RNA – (translation)  protein synthesis Genotype ------  phenotype Genotype ------  phenotype

17. Garrod 1900’s Children -> defect in 2 a.a. due to defect in the enz. That helps make the a.a Children -> defect in 2 a.a. due to defect in the enz. That helps make the a.a Phenylalanine->PKU Phenylalanine->PKU Tyrosine ->albinism Tyrosine ->albinism Gene  enzyme  amino acid (can’t be made) Gene  enzyme  amino acid (can’t be made) Couldn’t prove it due to lack of technology Couldn’t prove it due to lack of technology

18. George Beadle & Edward Tatum 1940’s American Geneticists ONE GENE ONE ENZYME (polypeptide) HYPOTHESIS: the function of a gene is to dictate the production of a specific enzyme. ONE GENE ONE ENZYME (polypeptide) HYPOTHESIS: the function of a gene is to dictate the production of a specific enzyme. Experimented with bread mold  lacked an enzyme in a metabolic pathway that produced some molecules that mold needed to produce an amino acid called arginine. Experimented with bread mold  lacked an enzyme in a metabolic pathway that produced some molecules that mold needed to produce an amino acid called arginine.

19. Tatum & Beadle 1958 Nobel Prize Proved Garrod correct Proved Garrod correct Bread mold -> can make all of it’s own a.a. that it needs Bread mold -> can make all of it’s own a.a. that it needs Gene -> enzyme -> amino acid Gene -> enzyme -> amino acid One gene = enzyme One gene = enzyme One gene = one protein!! One gene = one protein!!

20. RNA RIBONUCLEIC ACID SINGLE STRANDED SINGLE STRANDED RESPONSIBLE FOR BRINGING THE GENETIC INFO. FROM THE NUCLEUS TO THE CYTOSOL! RESPONSIBLE FOR BRINGING THE GENETIC INFO. FROM THE NUCLEUS TO THE CYTOSOL!

21. RNA Nucleotide Phosphate group Phosphate group Sugar molecule (ribose) Sugar molecule (ribose) Nitrogenous bases Nitrogenous bases Adenine – URACIL Adenine – URACIL Cytosine - guanine Cytosine - guanine

22. 3 Kinds of RNA mRNA – (messenger) brings info from DNA in nucleus to cytosol in eukaryotic cells (uncoiled) mRNA – (messenger) brings info from DNA in nucleus to cytosol in eukaryotic cells (uncoiled) tRNA –(transfer) brings amino acids to mRNA for translation (hairpin shape) tRNA –(transfer) brings amino acids to mRNA for translation (hairpin shape) rRNA –(ribosomal) most abundant, rRNA makes up the ribosomes where proteins are made (globular) rRNA –(ribosomal) most abundant, rRNA makes up the ribosomes where proteins are made (globular)

23. TRANSCRIPTION!! DNA  RNA 1.RNA polymerase-initiates transcription by binding to region on DNA called PROMOTER (causes DNA to separate)-INITIATION PHASE 1.RNA polymerase-initiates transcription by binding to region on DNA called PROMOTER (causes DNA to separate)-INITIATION PHASE 2. only ONE of the DNA chains will be used for transcription it’s called the TEMPLATE (promoter dictates which of the two strands will be used) 2. only ONE of the DNA chains will be used for transcription it’s called the TEMPLATE (promoter dictates which of the two strands will be used) 3. RNA POLYMERASE – attached to first DNA nucleotide of template chain – then begins adding complementary RNA nucleotides- ELONGATION PHASE 3. RNA POLYMERASE – attached to first DNA nucleotide of template chain – then begins adding complementary RNA nucleotides- ELONGATION PHASE

24. Cont. Transcription 4. transcription continues until RNA polymerase reaches a TERMINATION SIGNAL on the DNA-TERMINATION PHASE 4. transcription continues until RNA polymerase reaches a TERMINATION SIGNAL on the DNA-TERMINATION PHASE 5. RNA polymerase releases both the DNA mol. And newly formed RNA mol. Are transcribed in this way (all three!!!) 5. RNA polymerase releases both the DNA mol. And newly formed RNA mol. Are transcribed in this way (all three!!!)

25. RNA *

26. RNA replications

27. PROKARYOTES Transcription and translation occur in the SAME place! Transcription and translation occur in the SAME place! NO NUCLEUS! NO NUCLEUS!

28. Eukaryotes 1. Before RNA leaves the nucleus: 1. Before RNA leaves the nucleus: G (guanine) cap is attached G (guanine) cap is attached A (adenine) tail is attached “many” A (adenine) tail is attached “many” 2. These protect the RNA from attack by cellular enzymes and help ribosomes to recognize the mRNA (cap & tail are NOT translated) 2. These protect the RNA from attack by cellular enzymes and help ribosomes to recognize the mRNA (cap & tail are NOT translated)

29. Cont. Eukaryotes 3. INTRONS (non coding sequence) are removed 3. INTRONS (non coding sequence) are removed 4. EXONS (part of gene that are expressed) are joined to produce a mRNA molecule with a continuous coding sequence. 4. EXONS (part of gene that are expressed) are joined to produce a mRNA molecule with a continuous coding sequence. NOW RNA CAN LEAVE THE NUCLEUS! NOW RNA CAN LEAVE THE NUCLEUS!

31. Protein Synthesis PROTEINS CARRY OUT THE GENETIC INSTRUCTIONS ENCODED IN AN ORGANISM’S DNA!!!! PROTEINS CARRY OUT THE GENETIC INSTRUCTIONS ENCODED IN AN ORGANISM’S DNA!!!!

32. TRANSLATION The process of assembling from info. Encoded in a mRNA! 1. mRNA leaves nucleus 1. mRNA leaves nucleus 2. mRNA migrates to ribosome in cytosol for protein synthesis 2. mRNA migrates to ribosome in cytosol for protein synthesis 3.amino acids floating in cytosol are transported to ribosomes by tRNA molecule 3.amino acids floating in cytosol are transported to ribosomes by tRNA molecule 4. peptide bonds join the amino acids to make polypeptide chain 4. peptide bonds join the amino acids to make polypeptide chain

33. Vocabulary! 1. GENETIC CODE: correlation between a nucleotide sequence and an amino acid sequence 1. GENETIC CODE: correlation between a nucleotide sequence and an amino acid sequence 2. CODON 3 mRNA nucleotides, codes for a specific amino acid (64) 2. CODON 3 mRNA nucleotides, codes for a specific amino acid (64) 3. START CODON (AUG) & a.a. methionine 3. START CODON (AUG) & a.a. methionine 4. STOP CODON (UAA, UAG, UGA) 4. STOP CODON (UAA, UAG, UGA) 5. ANTICODON – 3 tRNA nucleotides carrying a specific amino acid! 5. ANTICODON – 3 tRNA nucleotides carrying a specific amino acid!

34. Protein Synthesis *

35. *

36. !

37. THE SUMMARY!

38. Ribosome factory for polypeptides Two subunits: Two subunits: Large subunit (top) Large subunit (top) Small subunit (bottom) Small subunit (bottom)

39. P site – holds tRNA carrying growing polypeptide A Site – holds tRNA carrying the next amino acid to be added

40. Initiation Codon Marks the Start of an mRNA message 3 PHASES: 3 PHASES: 1. INITIATION 1. INITIATION 2. ELONGATION 2. ELONGATION 3. TERMINATION 3. TERMINATION

41. INITIATION ( 2 steps) A) An mRNA mol. Binds to a small ribosomal subunit. A special initiator tRNA binds to the specific codon called the START CODON (UAC binds to start codon AUG  methionine) A) An mRNA mol. Binds to a small ribosomal subunit. A special initiator tRNA binds to the specific codon called the START CODON (UAC binds to start codon AUG  methionine) B) A large ribosomal subunit binds to the small one creating a functional ribosome. The initiator tRNA fits into the P site of the ribosome. B) A large ribosomal subunit binds to the small one creating a functional ribosome. The initiator tRNA fits into the P site of the ribosome.

42. Elongation and Termination Elongation adds amino acids to the polypeptide chain until a stop codon terminates translation. Elongation adds amino acids to the polypeptide chain until a stop codon terminates translation.

43. 3 Steps of Elongation 1. Codon recognition  anticodon of incoming tRNA carrying amino acid pairs with mRNA codon in A site. 1. Codon recognition  anticodon of incoming tRNA carrying amino acid pairs with mRNA codon in A site. 2. Peptide bond formation  polypeptide separates from tRNA (fr. P site). Peptide bond forms between amino acid in P & A site  ribosome catalyzes formation of bond. 2. Peptide bond formation  polypeptide separates from tRNA (fr. P site). Peptide bond forms between amino acid in P & A site  ribosome catalyzes formation of bond. CONTINUE….. CONTINUE…..

44. CONTINUE… 3. Translation  P site tRNA now leaves ribosome, the ribosome translocates (moves) the tRNA in the A site, with its attached polypeptide to the P site. The codon and anticodon remain bonded and the mRNA and tRNA move as a unit. This movement brings into the A site the next mRNA codon to be translated and process can start again! ELONGATION CONTINUES UNTIL A STOP CODON REACHES A SITE. 3. Translation  P site tRNA now leaves ribosome, the ribosome translocates (moves) the tRNA in the A site, with its attached polypeptide to the P site. The codon and anticodon remain bonded and the mRNA and tRNA move as a unit. This movement brings into the A site the next mRNA codon to be translated and process can start again! ELONGATION CONTINUES UNTIL A STOP CODON REACHES A SITE.