1. From Gene To Protein Chapter 17

2. The Connection Between Genes and Proteins Proteins - link between genotype (what DNA says) and phenotype (physical expression) Beadle and Tatum – 1 st to make connection between genes and enzymes that carry out genes through bread mold experiments.

3. http://fig.cox.miami.edu/~cmallery/150/gene/17x3.jpg

4. Bridge between DNA, proteins - RNA. RNA similar to DNA - sugar ribose; contains uracil instead of thymine. RNA single-stranded.

5. http://gibk26.bse.kyutech.ac.jp/jouhou/image/nucleic/rna/rna_bb_st.gif

6. Nucleotides found in DNA and RNA - code - determines order of amino acids. 2 steps - transcription and translation.

7. http://www.ktf-split.hr/glossary/image/nucleotide.gif

8. Transcription - DNA serves as template for complementary RNA strand. Transcription produces mRNA strand (messenger RNA). Translation uses mRNA sequence to determine order of amino acids - creates polypeptide.

9. http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/graphics/Transcription.02.GIF

10. Bacteria - transcription and translation occur at once.

12. Eukaryotes, most transcription occurs in nucleus, translation occurs at ribosome. Before primary transcript can leave nucleus - modified during RNA processing before enters cytoplasm.

14. Genetic code consists of triplet code - series 3 nitrogen bases that code for specific amino acid. 64 possible combinations of nitrogen bases. Only 20 amino acids = each amino acid has more than 1 code.

15. http://www.dls.ym.edu.tw/lesson/gen.files/codon.jpg

16. 61 of 64 codes specific to an amino acid. Other 3 - stop codons - determine when process stops. Specific code that signals start of translation - also codes for amino acid. Start begins correct reading frame of polypeptide.

18. Transcription, 1 DNA strand - template strand, provides template for ordering sequence of nucleotides in RNA transcript. Translation, blocks of 3 nucleotides, codons, decoded into sequence of amino acids.

20. Possible to take genetic code of 1 organism, place it into another - nearly universal. Firefly gene for luminescence transplanted into tobacco plant. Bacteria can be inserted with specific genes to synthesize genes in large amounts.

22. Synthesis and Processing of RNA mRNA transcribed from template of original gene. RNA polymerase separates DNA strands and bonds RNA bases along complementary strand. Bases can only be added to 3’ end.

23. http://www.csu.edu.au/faculty/health/biomed/subjects/molbol/images/7_9.jpg

24. Specific sequences determine where transcription starts and where it ends. Promoter – initiates; terminator ends. 3 stages in transcription.

26. Presence of promotor sequence determines which strand of DNA helix is template. Proteins (transcription factors) recognize promotor region, especially a TATA box, bind to promotor.

27. After they have bound to promotor, RNA polymerase binds to transcription factors to create transcription initiation complex. RNA polymerase starts transcription.

29. RNA polymerase moves along - nucleotides added to 3’ end. Single gene can be transcribed simultaneously by several RNA polymerases at a time. Growing strand of RNA trails off from each polymerase.

31. RNA splicing - removal of large portion of RNA molecule. Most eukaryotic genes and RNA transcripts have long noncoding stretches of nucleotides. Noncoding segments, introns, lie between coding regions. Coding regions - exons.

32. http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/nucleic/chpt15/introndeletion.gif

33. RNA splicing removes introns, joins exons to create mRNA molecule with continuous coding sequence.

35. Splicing done by spliceosome.

37. The Synthesis of Proteins Translation - cell interprets series of codons along mRNA molecule. Transfer RNA (tRNA) transfers amino acids from cytoplasm’s pool to ribosome. Ribosome adds each amino acid carried by tRNA to growing end of polypeptide chain.

39. Translation - tRNA links mRNA codon with appropriate amino acid. tRNA arriving at ribosome carries specific amino acid at 1 end, has specific nucleotide triplet, anticodon, at other. Anticodon base-pairs with complementary codon on mRNA.

40. http://bioweb.uwlax.edu/GenWeb/Molecular/Theory/Translation/ribosome.jpg

41. tRNA synthesized like other forms of RNA. Once in cytoplasm, each tRNA used repeatedly to pick up and drop off that amino acid.

43. Anticodons of tRNA recognize more than one codon. Rules for base pairing between 3 rd base of codon and anticodon relaxed (wobble).

44. http://www.geneticengineering.org/chemis/Chemis-NucleicAcid/Graphics/tRNA.jpg

45. Each ribosome has binding site for mRNA 3 binding sites for tRNA molecules. P site holds tRNA carrying growing polypeptide chain. A site carries tRNA with next amino acid. Discharged tRNAs leave ribosome at E site.

47. Translation divided into 3 stages: initiation elongation termination

48. http://nobelprize.org/educational_games/medicine/dna/a/translation/pics/translation2.gif

49. Initiation brings together mRNA, tRNA with 1 st amino acid, 2 ribosomal subunits.

51. Elongation - series of 3-step cycles as each amino acid added to previous one. 3 steps of elongation continue codon by codon to add amino acids until polypeptide chain completed.

52. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 17.18

53. Termination - 1 of 3 stop codons reaches A site. Release factor binds to stop codon, hydrolyzes bond between polypeptide and tRNA in P site. Frees polypeptide, translation complex disassembles.

55. 2 types of ribosomes active in process. 1 Free ribosomes suspended in cytosoll synthesize proteins in cytosol. 2 Bound ribosomes attached to cytosolic side of endoplasmic reticulum.

56. Fig. 17.21 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

57. Bacteria and eukaryotes have differences in cellular machinery and in details of processes. Eukaryotic RNA polymerases differ from prokaryotic; require transcription factors.

58. http://www.personal.psu.edu/faculty/r/c/rch8/workmg/TxnPromotersCh11_files/image052.png

59. Differ in how transcription terminated. Ribosomes also different. Prokaryotes can transcribe and translate same gene simultaneously.

61. Mutations - changes in genetic material of cell (or virus). Chemical change in 1 base pair of gene causes point mutation. Occur in gametes or cells producing gametes - may be transmitted to future generations.

62. http://staff.jccc.net/PDECELL/evolution/mutations/mutypes.gif

63. Point mutation that results in replacement of pair of complementary nucleotides with another nucleotide pair - base-pair substitution. Some base-pair substitutions have little or no impact on protein function (silent mutations).

64. http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/26_DNA_Transcription_files/image008.jpg

65. Other base-pair substitutions cause readily detectable change in protein. Missense mutations - still code for amino acid, change indicated amino acid. Nonsense mutations change amino acid codon into stop codon, nearly always leading to nonfunctional protein.

66. Fig. 17.24 Copyright © Pearson Education, Inc., publishing as Benjamin Cummings

67. Insertions and deletions - additions or losses of nucleotide pairs in gene. Unless these mutations occur in multiples of 3 - cause frameshift mutation.

68. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 17.24

69. Mutations can occur in number of ways. Errors can occur during DNA replication, DNA repair, or DNA recombination. Mutagens - chemical or physical agents that interact with DNA to cause mutations. Physical agents - high-energy radiation like X-rays and ultraviolet light.