Chapter 12 Packet DNA 1. What did Griffith conclude from his experiment? 2. Describe the process of transformation.

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1 Chapter 12 Packet DNA and RNA Name Period California State Standards covered by this chapter: Cell Biology 1. The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in specialized areas of the organism's cells. As a basis for understanding this concept: c. Students know how prokaryotic cells, eukaryotic cells (including those from plants and animals), and viruses differ in complexity and general structure. d. Students know the central dogma of molecular biology outlines the flow of information from transcription of ribonucleic acid (RNA) in the nucleus to translation of proteins on ribosomes in the cytoplasm. Genetics 4. Genes are a set of instructions encoded in the DNA sequence of each organism that specify the sequence of amino acids in proteins characteristic of that organism. As a basis for understanding this concept: a. Students know the general pathway by which ribosomes synthesize proteins, using trnas to translate genetic information in mrna. b. Students know how to apply the genetic coding rules to predict the sequence of amino acids from a sequence of codons in RNA. c. Students know how mutations in the DNA sequence of a gene may or may not affect the expression of the gene or the sequence of amino acids in an encoded protein. d. Students know specialization of cells in multicellular organisms is usually due to different patterns of gene expression rather than to differences of the genes themselves. e. Students know proteins can differ from one another in the number and sequence of amino acids. 5. The genetic composition of cells can be altered by incorporation of exogenous DNA into the cells. As a basis for understanding this concept: a. Students know the general structures and functions of DNA, RNA, and protein. b. Students know how to apply base-pairing rules to explain precise copying of DNA during semiconservative replication and transcription of information from DNA into mrna. Read the appropriate section in the textbook and lecture notes before answering the following questions. You must put all answers and definitions in your own words for full credit DNA 1. What did Griffith conclude from his experiment? 2. Describe the process of transformation. 3. What did Avery conclude from his experiment? 4. What is a bacteriophage? 5. What is the basic structure of a bacteriophage?

2 6. What did Hershey and Chase use to radioactively label the DNA and the protein coat of the bacteriophage? 7. What did Hershey and Chase conclude from their experiment? 8. The basic structure of a nucleotide includes 3 main parts. List them and include a labeled diagram. Structural Part Labeled Diagram a. b. c. 9. The nitrogenous bases of DNA include: a. Nitrogenous Base Class of organic molecule (purine or pyrimidine) b. c. d. 10. Describe the difference between the structure of a purine and the structure of a pyrimidine. 11. Describe Chargaff s Rules. 12. What is the overall shape of DNA? 13. The double helix structure was first described in 1953 by and.

3 14. Were it not for the X-ray diffraction photograph of DNA, taken by, these gentlemen would not have deduced the structure of DNA when they did. 15. The 2 strands of DNA are held together by between the bases. 16. What is the base-pairing pattern seen with the nucleotides of DNA? 17. Because of the base-pairing rules, if you know one of the strands of DNA you can determine its complementary strand. Along one strand of a double helix is the nucleotide sequence GGCATCGCAATTCGGCAT. What is the complementary sequence for the other DNA strand? 12-2 Chromosomes and DNA Replication 18. Distinguish a prokaryotic chromosome from a eukaryotic chromosome. 19. Chromatin: 20. Nucleosome: 21. During what stage of mitosis does the DNA coil up to form chromosomes? (Think back to Ch. 10) 22. During which specific phase of the cell cycle does DNA replication take place? (Think back to Ch. 10) DNA Replication NOTE: You will need to use the lecture notes to assist in some of your answers. 23. Why is it important that DNA replication occurs simultaneously at many points along the molecule?

4 24. What important roles do the following enzymes play during the replication process? Enzyme Role (function) DNA helicase DNA polymerase 12-3 RNA and Protein Synthesis 25. What is the function of a gene? 26. List 3 ways in which a molecule of RNA differs from a molecule of DNA. a. b. c. 27. Three types of RNA are made from DNA in the nucleus. RNA Molecule Abbreviation Description/Function a. Messenger RNA b. Transfer RNA c. Ribosomal RNA 28. Protein synthesis involves 2 main stages. Complete the following table. Process Location in a eukaryotic cell where process takes place Function a. Transcription b. Translation

5 29. How does RNA polymerase know where to start making an RNA copy of the DNA? 30. What are introns and exons? 31. Codon: 32. What is the start codon? 33. Which amino acid does the start codon code for? Use the dictionary of the genetic code (RNA codons) to answer the following questions. 34. An mrna molecule contains the nucleotide sequence CCAUUUACG. Translate this sequence into the corresponding amino acid sequence. 35. An mrna molecule contains the nucleotide sequence AUGAAAGCCGAUUAA. Translate this sequence into the corresponding amino acid sequence. 36. A DNA molecule contains the nucleotide sequence TACTTAGCCGATT. Give the corresponding mrna sequence and translate the sequence into the corresponding amino acid sequence. 37. Transcribe the following DNA molecule into the mrna sequence. Then determine the trna sequence and the amino acid sequence. DNA: TACCCTAGTTCCGGGATT a. mrna: b. trna: c. amino acids:

6 Transcription 38. Transcription takes place in the of the cell. 39. First, attaches to the region of a specific gene in DNA. 40. RNA polymerase unwinds the by breaking the bonds between the nucleotide strands. 41. then adds complementary RNA nucleotides to create a strand of mrna. 42. This continues until the RNA polymerase reaches the sequence on the DNA. RNA Editing Before the mrna can leave the nucleus and enter the cytoplasm, it must have some modifications made to it. 43. Introns are the regions of DNA and exons are the regions of DNA 44. The are removed and the are spliced together. 45. This final transcript of mrna exits the nucleus and enters the. Translation 46. Translation takes place in the. 47. First, a attaches to the mrna at the start codon,. 48. Next, a carrying the complementary attaches to the start codon on the mrna. 49. This trna carries the amino acid. 50. Another incoming carrying the complementary to the next codon enters the ribosome. 51. The ribosome forms a bond between the first and second creating a polypeptide chain. 52. The ribosome then moves to the next, where another incoming carrying the complementary to that codon enters the ribosome.

7 53. The polypeptide chain continues to grow until the ribosome reaches a. There are 3 stop codons,,, and. 54. When the ribosome reaches the, the polypeptide chain is released and ribosome detaches Mutations 55. mutation: 56. point mutation: 57. frameshift mutation: 58. What causes a point mutation in DNA to occur? 59. What causes a frameshift mutation in DNA to occur? 60. Are all mutations bad? Explain.