1. DNA and RNA Objectives Describe scientific contributions to the understanding of the DNA structure. Do Now! Write down key terms which relate to the structure of the DNA Molecule?

2. Frederick Griffith 1928 Transformation Transformation - process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

3. Oswald Avery 1944 World knows a molecule carries the genetic information. Doesn’t know if the molecule is a: protein, lipid, carbohydrate, RNA, or DNA Avery performs Griffith’s experiment again with a twist. Avery and other scientists discovered that DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next.

4. Hershey-Chase Experiment 1952 Good scientists are naturally skeptical. Hershey-Chase are testing to see if DNA is the molecule that carries genetic information. BacteriophageBacteriophage - virus that infects bacteria

5. Hershey-Chase Experiment

6. DNA and RNA Objectives Describe scientific contributions to the understanding of the DNA structure. Homework No response this Friday, still read Ch. 16-18 DNA Extraction Lab Due Thursday Do Now!! 1.List the conclusions and how each of these scientist got there: –Griffith –Avery –Hershey and Chase

7. DNA Structure Nucleotide - monomer of nucleic acids made up of a 5- carbon sugar, a phosphate group, and a nitrogenous base

8. Sugar-Phosphate Backbone and Chargaff’s Rule Simply states: If I have a certain number of Cytosines I will have about the ______ number of Guanines. Same with A’s and T’s.

9. Rosalind Franklin 1950 X-Ray Diffraction Clues from the X-Ray –Coiled (forming Helix) –Double- stranded –Nitrogeneous bases are in the center

10. Watson & Crick Francis Crick – British physicist James Watson – American Biologist –Building a 3D model of DNA –Franklin’s X-Ray opened their eyes to the Double Helix Watson and Crick’s model of DNA was a double helix, in which two strands were wound around each other.

11. Double Helix

12. 1.List the conclusions and how each of these scientist got there: –Griffith –Avery –Hershey and Chase 2.How did Watson and Crick’s model explain why there are equal amounts of thymine and adenine in DNA? 3.Why did Hershey and Chase grow viruses in cultures that contained both radioactive phosphorus and radioactive sulfur? What might have happened if they only used one?

13. DNA and RNA Objectives Describe scientific contributions to the understanding of the DNA structure. Homework No response this Friday, still read Ch. 16-18 DNA Extraction Lab Due Today Handout Due Tomorrow Do Now!! How did Watson and Crick’s model explain why there are equal amounts of thymine and adenine in DNA?

14. Prokaryote DNA Prokaryotes –No Nucleus one circular chromosome –Most have one circular chromosome located in the cytoplasm with some plasmids as well –E.Coli (1.6μm diameter) –4,639,221 base pairs 1.6mm long –Like packing 300m of rope in your backpack

15. Eukaryotes and DNA 1000 time more base pairs than bacterial DNA Smallest human chromosome has 30million base pairs of DNA How do eukaryotes fit all that DNA in its nucleus?

16. DNA to Chromosomes Vocab –Chromatin - granular material (less condensed) within the nucleus; consists of DNA tightly coiled around proteins –Chromosomes – condensed chromatin –Histone - globular protein molecule around which DNA is tightly coiled in chromatin

18. DNA Replication During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template, or model, for the new strand.

19. 1.Enzymes unwind DNA 2.Enzymes split “unzip” double helix DNA polymerase, 3.The enzyme, DNA polymerase, finds and attaches the corresponding N- base 4.Each “old” stand serves as a template and is matched up with a new stand of DNA 5.New helixes wind back up.

20. Bubbles and Forks

21. DNA Polymerase

22. DNA polymerases can only add nucleotides to the free 3’ end of a growing DNA strand leading strand - used by polymerases as a template for a continuous complimentary strand lagging strand - copied away from the fork in short segments (Okazaki fragments)

23. DNA polymerase and Primers Polymerase cannot initiate synthesis of a polynucleotide –can only add nucleotides to the end of an existing chain To start a new chain requires a primer –a short segment of RNA

24. Replication Fork - Topoisomerases - Helicases - Single-strand binding proteins - Primases (RNA primers) - DNA Polymerases - Ligases Animation: Leading Strand Animation: Leading Strand Animation: Lagging Strand Animation: Lagging Strand

25. DNA polymerase later replaces the primer with deoxyribonucleotides complimentary to the template Animation: DNA Replication Review Animation: DNA Replication Review

27. Protein Synthesis Objectives The central Dogma of molecular biology Homework Pass in Chapter 10 question set. Quick Quiz on Friday – Multiple Choice. Do Now!! –What is the central Dogma of molecular biology?

28. RNA and Protein Synthesis Codon - three-nucleotide sequence on messenger RNA that codes for a single amino acid Anticodon - group of three bases on a tRNA molecule that are complementary to an mRNA codon

29. Protein Synthesis Two Main Parts Transcription –Formation of a single strand of messenger RNA from DNA in the nucleus Translation –Occurs on ribosomes –Cell uses the information on mRNA to assemble amino acids in the proper order to form specific proteins

30. Transcription 1.Occurs in nucleus 2.Enzymes unwind DNA 3.Enzymes split “unzip” double helix 4.RNA Polymerase binds to promoter sequence on DNA 5.RNA Polymerase transcribes a single strand of mRNA

31. Translation

33. binding site for mRNA The P site holds the tRNA carrying the polypeptide chain The A site carries the tRNA with the next amino acid Discharged tRNAs leave the ribosome at the E site

34. Genes and Proteins Most genes only have instructions for assembling proteins. If that’s the case what do proteins have to do with eye color, hair color or height?

36. Protein Synthesis Objectives Describe the process of RNA editing. Identify and describe different types of gene mutations. Homework Quick Quiz on Friday – Multiple Choice. –The scientists –DNA Replication –Protein Synthesis –Compare DNA/RNA Do Now!! –Take out the do now we were working on yesterday.

37. mRNA Editing before going to transcription Intron - intervening sequence of DNA; does not code for a protein (not used) Exon - expressed sequence of DNA; codes for a protein (used)

38. RNA splicing Most eukaryotic genes and their RNA transcripts have long noncoding stretches of nucleotides Spliceosome  removes introns and joins exons to create an mRNA molecule with a continuous coding sequence

39. Mutations Mutation - change in a DNA sequence that affects genetic information Two Main Types: –Gene Mutation Mutation that causes a change in a single gene –Chromosomal Mutation Mutation that causes a change in an entire chromosome

40. 13.3 Mutations Gene Mutations Chromosomal Mutations

41. Gene Mutations Point Mutation (substitution) mutation that affects a single nucleotide, usually by substituting one nucleotide for another Point Mutation –Frameshift Mutation (insertion or deletion) mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide

42. Fig. 17-23 Wild-type 3 DNA template strand 5 5 5 3 3 Stop Carboxyl end Amino end Protein mRNA 3 3 3 5 5 5 A instead of G U instead of C Silent (no effect on amino acid sequence) Stop T instead of C 3 3 3 5 5 5 A instead of G Stop Missense A instead of T U instead of A 3 3 3 5 5 5 Stop Nonsense No frameshift, but one amino acid missing (3 base-pair deletion) Frameshift causing extensive missense (1 base-pair deletion) Frameshift causing immediate nonsense (1 base-pair insertion) 5 5 5 3 3 3 Stop missing 3 3 3 5 5 5 Stop 5 5 5 3 3 3 Extra U Extra A (a) Base-pair substitution(b) Base-pair insertion or deletion

43. Cystic Fibrosis

44. changes in chromosome structure  deletion  a chromosome fragment lacking a centromere is lost during cell division  duplication  a fragment becomes attached as an extra segment to a sister chromatid

45. Chromosomal Mutations  inversion  a chromosomal fragment reattaches to the original chromosome in the reverse orientation  translocation  a chromosomal fragment joins a nonhomologous chromosome

46. Nondisjunction  Problems with the meiotic spindle cause errors in daughter cells

47. Aneuploidy  Trisomic cells  three copies of a particular chromosome type 2n + 1 total chromosomes  Monosomic cells  only one copy of a particular chromosome type 2n - 1 chromosomes

48. Polyploidy  Organisms with more than two complete sets of chromosomes  Relatively common among plants and much less common among animals fishes and amphibians have polyploid species

49. Outcome  Most of these alterations are so disastrous that the embryos are spontaneously aborted long before birth

50. Gene Regulation

51. Prokaryote Gene Regulation –Will have one OPERATOR (regulatory site) controlling the expression of more than one gene. OPERON Eukaryote Gene Regulation –Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon

52. Gene Regulation Vocab Promoter - region of DNA that indicates to RNA polymerase where to bind to make RNA Operon - group of genes operating together Operator - region of chromosome in an operon to which the repressor binds when the operon is “turned off”

53. Lac Operon (E. coli) Operator bound – RNA polymerase can’t transcribe genetic information(not expressed) Operator free – gene(s) expressed

54. Eukaryote Gene Regulation DNA region about 30bp long TATATAAA: help to align RNA Polymerase Genes are regulated in a variety of ways by enhancer sequences

55. Gene Reg. and Development hox genes - series of genes that controls the organs and tissues that develop in various parts of an embryo Mutations affecting the hox genes in the fruit fly, Drosophila, for example, can replace the fly’s antennae with a pair of legs growing right out of its head!

56. 1.What is meant by term base pairing? How is base pairing involved in DNA replication? 2.When a DNA molecule is replicated, how do the new molecules relate to the original molecule? 3.What is the difference between introns and exons? 4.What is a codon?anticodon? How do they relate? 5.Explain why controlling proteins in an organism controls the organism’s traits. 6.Name two major types of mutations. What do they have in common? How are they different? Give an example of each. 7.The word transcribe means “to write out”, and the word translate means “to express in another language.” Review the meanings of transcription and translation in genetics. How do the technical meanings of these words relate to meanings of the words in ordinary language?