1. Chapter 12 DNA and RNA

2. C. Griffith made two observations: (1) The disease-causing (virulent) strain S-strain of bacteria grew into smooth colonies on culture plates. (2) The harmless strain (R-strain) grew into colonies with rough edges. I. Griffith and Transformation A. 1928- British scientist Fredrick Griffith learned how certain types of bacteria caused pneumonia. B. He isolated two different strains of pneumonia bacteria from mice and grew them in his lab.

3. D. Griffith's Experiments 1. set up four individual experiments a. Experiment 1: Mice injected with the disease-causing- (virulent) strain of bacteria, mice got pneumonia = mice died.

4. b. Experiment 2: Mice injected with harmless strain of bacteria = Mice live

5. c. Experiment 3: Griffith heated the disease-causing bacteria, injected the heat-killed bacteria into the mice = mice lived

6. d. Experiment 4: heat- killed, disease-causing bacteria + live, harmless bacteria and injected the mixture into the mice =mice got pneumonia and died. 2. Griffith concluded - the heat-killed bacteria passed their disease- causing ability to the harmless strain.

7. a. Griffith - transformation - one strain of bacteria (the harmless strain) had changed permanently into another (the disease-causing strain). 3. Transformation b. Griffith hypothesized that a factor must contain info. that could change harmless bacteria into disease-causing ones.

8. II. Avery and DNA A. 1944, repeats Griffith’s work 2. Avery destroyed DNA 1. 1 st stage – destroyed all macromolecules except DNA a. Transformation still occurred a. No transformation occurred 3. Conclusion - transforming factor in bacteria = DNA

9. III. Hershey-Chase Experiment A. 1952 – worked with T2 bacteriophages (virus that infects and kills bacteria) -composed of DNA core with a protein coat B. Attaches to bacterium and injects its DNA (viral genes)-makes bacterium a virus factory- “hijacks” cell- produces new T2 bacteriophages and gradually destroys bacterial cell C. The cell splits open and hundreds of new viruses burst out D. Hershey-Chase determined it was the DNA that entered and infected the cell by using radioactive isotopes

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11. IV. Structure of DNA A. Made up of Nucleotides 1. Sugar (Deoxyribose) 2. Phosphate 3. Nitrogen Base B. Four nucleotides 1. Adenine  A 2. Guanine  G 3. Thymine  T 4. Cytosine  C

12. C. Chargaff’s Rules = Base pairing Rules 1. A is found in equal amount to T and C is found in equal amount to G 2. Therefore, A = T and C = G D. X-Ray Evidence 1. Rosalind Franklin used X-Ray diffraction to take a picture of DNA E. Watson and Crick 1. Used Franklin’s picture of DNA 2. Found out DNA is a double helix (twisted ladder)

13. DNA Double Helix Page 294

14. V. DNA A. Prokaryotes DNA is located in cytoplasm B. Eukaryotes DNA is located in the nucleus 1. Single circular DNA- one chromosome with several genes 1. 1,000 X more DNA 2. DNA & protein (histones) = chromatin a. Form beadlike structure = nucleosome b. Chromatin tightly coiled up = chromosome i. Helps fold long DNA to fit into the tiny space

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16. VI. DNA Replication (Page 298) A. DNA molecule produces 2 new complementary strands C. Helicase unwinds and “unzips” DNA (hydrogen bonds are broken between base pairs) E. Free floating nucleotides attach to each template B. Starts at a single point (replication fork) and proceeds in two directions F. DNA polymerase (enzyme) proofreads new strands G. Each strand contains an old strand and a new strand of DNA- called SEMI-CONSERVATIVE REPLICATION D. Each strand serves as a template

17. Replication Fork Growth New StrandOriginal strand Nitrogen Bases DNA Polymerase Page 298

18. VII. RNA A. Single strand of nucleotides (instead of double) a. Cytosine = Guanine 2. Base pairing – NO THYMINE: b. Adenine = Uracil B. Types of RNA 1. Messenger RNA (mRNA): Carries instructions for making proteins from DNA to ribosome 2. Ribosomal RNA (rRNA): Makes up ribosomes- helps assemble proteins 3. Transfer RNA (tRNA): Transfers amino acids to the ribosome 1. Sugar is RIBOSE (instead of deoxyribose in DNA)

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20. Page 301 Transcription

21. VIII. GENE EXPRESSION Part I-Transcription (p. 301) A. mRNA makes a copy of DNA – RNA Polymerase B. Starts at promoter site on DNA C. RNA nucleotides pair up with DNA to make mRNA D. mRNA leaves nucleus:Goes to ribosome E. TRANSCRIPTION = making mRNA from DNA

22. Page 302 RNA Editing- occurs before leaving nucleus Honors Bio Info. Poly-A CapGuanine Tail

23. IX. RNA Editing-Before leaving nucleus A. Exon – expressed- sequence of DNA -codes for protein B. Intron – interrupting noncoding sequences of DNA - does not code for protein C. mRNA strand – introns cut out, so only exons left D. Final mRNA transcript = exons spliced together; cap and tail are added (prevents degradation/damage on the way to ribosome) Why is this editing important to organisms? 1. One gene on DNA can be cut and spliced to make different RNA strands for different versions of a protein 2. Role in evolution – very small changes in DNA have large effects in gene expression (phenotypes)

24. X. Genetic Code – Triplet Code A. Three bases read at a time = a one “word” (one amino acid) B. Codon = sequence of three bases on mRNA that codes for a specific amino acid 1. Four different letters used to code for 20 amino acids 2. 4 x 4 x 4 = 64 possible codes for 20 amino acids 3. A single amino acid may have many codons 4. Start codon = AUG = Methionine (amino acid) 5. Stop codon = UGA, UAA, or UAG

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26. Pages 304 - 305 Translation

27. Ribosome mRNA Methionine Phenylalanine tRNA Lysine Start codon

30. XI. GENE EXPRESSION Part II- Translation A. Decoding of mRNA into protein (polypeptide chain) B. Begins when mRNA attaches to ribosome at start codon C. Each codon moves through ribosome and correct amino acid is brought to ribosome by tRNA 1. Anticodon on tRNA pairs with codon on mRNA 2. Anticodon = sequence of three bases on tRNA D. Peptide bond forms between amino acids E. mRNA move through until stop codon F. New protein (polypeptide chain) and mRNA are released from ribosome

31. T A C A T G DNA Strand: A T G T A C mRNA Strand : A U G U A C (From top DNA strand) Amino Acids = tRNA bases = anticodon U A C A U G Methionine - Tyrosine

32. 1. Transcription 2. Translation GENE EXPRESSION

33. XII. Mutations A. Mutation = change in genetic material B. Gene Mutation = Change in a single gene 1. Point mutation = change in a single nucleotide a. Subsitution with no effect = no a.a change b. Subsitution with effect = amino acid change = protein change

34. 1. Insertion = one nucleotide is added 2. Deletion = one nucleotide is taken away c. Frameshift Mutations 3. Shifts reading frame = change in amino acids down the chain

36. C. Chromosomal Mutations 1. Deletion = loss of part or entire chromosome 2. Duplication = a segment of chromosome is repeated

37. 3. Inversion = part of chromosome becomes reversed 4. Translocation = part of one chromosome breaks off and attaches to another

38. D. Polyploidy- having more than 2 sets of chromosomes 1. Beneficial mutation in which entire sets of chromosomes are duplicated Ex. Triploid = 3n Tetraploid = 4n 2. Polyploid plants are larger and stronger (hardier or more tolerant to adverse conditions) than diploid counterparts Ex. Bananas, strawberries, and many citrus fruits

39. 12–1 Avery and other scientists discovered that A. DNA is found in a protein coat. B. DNA stores and transmits genetic information from one generation to the next. C. transformation does not affect bacteria. D. proteins transmit genetic information from one generation to the next.

40. 12–1 The Hershey-Chase experiment was based on the fact that A. DNA has both sulfur and phosphorus in its structure. B. protein has both sulfur and phosphorus in its structure. C. both DNA and protein have no phosphorus or sulfur in their structure. D. DNA has only phosphorus, while protein has only sulfur in its structure.

41. 12–1 DNA is a long molecule made of monomers called A. nucleotides. B. purines. C. pyrimidines. D. sugars.

42. 12–1 Chargaff's rules state that the number of guanine nucleotides must equal the number of A. cytosine nucleotides. B. adenine nucleotides. C. thymine nucleotides. D. thymine plus adenine nucleotides.

43. 12–1 In DNA, the following base pairs occur: A. A with C, and G with T. B. A with T, and C with G. C. A with G, and C with T. D. A with T, and C with T.

44. Copyright Pearson Prentice Hall 12–2 In prokaryotic cells, DNA is found in the A. cytoplasm. B. nucleus. C. ribosome. D. cell membrane.

45. Copyright Pearson Prentice Hall 12–2 The first step in DNA replication is A. producing two new strands. B. separating the strands. C. producing DNA polymerase. D. correctly pairing bases.

46. Copyright Pearson Prentice Hall 12–2 A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand? A. GCGAATTCG B. CGCTTAAGC C. TATCCGGAT D. GATGGCCAG

47. Copyright Pearson Prentice Hall 12–2 In addition to carrying out the replication of DNA, the enzyme DNA polymerase also functions to A. unzip the DNA molecule. B. regulate the time copying occurs in the cell cycle. C. “proofread” the new copies to minimize the number of mistakes. D. wrap the new strands onto histone proteins.

48. Copyright Pearson Prentice Hall 12–2 The structure that may play a role in regulating how genes are “read” to make a protein is the A. coil. B. histone. C. nucleosome. D. chromatin.

49. Copyright Pearson Prentice Hall 12–3 The role of a master plan in a building is similar to the role of which molecule? A. messenger RNA B. DNA C. transfer RNA D. ribosomal RNA

50. Copyright Pearson Prentice Hall 12–3 A base that is present in RNA but NOT in DNA is A. thymine B. uracil. C. cytosine. D. adenine.

51. Copyright Pearson Prentice Hall 12–3 The nucleic acid responsible for bringing individual amino acids to the ribosome is A. transfer RNA. B. DNA. C. messenger RNA. D. ribosomal RNA.

52. Copyright Pearson Prentice Hall 12–3 A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the A. intron. B. exon. C. promoter. D. codon.

53. Copyright Pearson Prentice Hall 12–3 A codon typically carries sufficient information to specify a(an) A. single base pair in RNA. B. single amino acid. C. entire protein. D. single base pair in DNA.

54. Copyright Pearson Prentice Hall 12–4 A mutation in which all or part of a chromosome is lost is called a(an) A. duplication. B. deletion. C. inversion. D. point mutation.

55. Copyright Pearson Prentice Hall 12–4 A mutation that affects every amino acid following an insertion or deletion is called a(an) A. frameshift mutation. B. point mutation. C. chromosomal mutation. D. inversion.

56. Copyright Pearson Prentice Hall 12–4 A mutation in which a segment of a chromosome is repeated is called a(an) A. deletion. B. inversion. C. duplication. D. point mutation.

57. Copyright Pearson Prentice Hall 12–4 The type of point mutation that usually affects only a single amino acid is called A. a deletion. B. a frameshift mutation. C. an insertion. D. a substitution.

58. Copyright Pearson Prentice Hall 12–4 When two different chromosomes exchange some of their material, the mutation is called a(an) A. inversion. B. deletion. C. substitution. D. translocation.