1. DNA & Protein Synthesis Honors Biology

2. History Before the 1940’s scientists didn’t know what material caused inheritance. They suspected it was either DNA or proteins.

3. History A series of experiments proved that DNA was the genetic material responsible for inheritance.

4. Frederick Griffith Injected mice with different types of pneumonia bacteria Results showed some type of factor was transferred from killed cells to live cells Griffith called this transformation

5. Oswald Avery Repeated Griffith’s idea to find how transformation happens Result _ DNA was the factor responsible for transformation

6. History In 1952, Alfred Hershey and Martha Chase did an experiment using a virus that infects E. coli bacteria. The experiment proved that DNA and not protein is the factor that influences inheritance.

8. History Erwin Chargaff discovered the base pairing rules and ratios for different species. Adenine pairs with Thymine Cytosine pairs with Guanine.

9. History Rosalind Franklin & Maurice Wilkins had taken the 1 st pictures of DNA using X-ray crystallization

10. This proved that DNA had a helical shape.

11. History The Nobel Prize in Medicine 1962 Francis Harry Compton Crick James Dewey Watson Maurice Hugh Frederick Wilkins Rosalind Franklin (Died of cancer 1958)

12. Wilkins has become a historical footnote and Watson & Crick are remembered as the Fathers of DNA WatsonCrick

15. DNA O O=P-O OPhosphate Group Group N Nitrogenous base (A, T, G, C) (A, T, G, C) CH2 O C1C1 C4C4 C3C3 C2C2 5 Sugar Sugar(deoxyribose)

16. Nitrogen Bases 2 types of Nitrogen Bases –Purines Double ring –G & A –Pyrimidines Single ring –C & U & T PGA CUT PY

17. DNA - double helix P P P O O O 1 2 3 4 5 5 3 3 5 P P P O O O 1 2 3 4 5 5 3 5 3 G C TATA

18. DNA The genetic code is a sequence of DNA nucleotides in the nucleus of cells.

19. DNA DNA is a double- stranded molecule. The strands are connected by complementary nucleotide pairs (A-T & C-G) like rungs on a ladder. The ladder twists to form a double helix.

20. DNA During S stage in interphase, DNA replicates itself. DNA replication is a semi- conservative process.

21. DNA Semi-conservative means that you conserve part of the original structure in the new one. You end up with 2 identical strands of DNA.

22. DNA Replication Step 1: Helicase unzips a molecule of DNA @ the hydrogen bonds between base pairs (breaking the H bonds). Step 2: DNA polymerase joins individual nucleotides to produce a DNA molecule which is a polymer and it also “proofreads” each new DNA strand Step 3: Ligase links the two sections together.

23. DNA Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc.) A gene is a stretch of DNA.

24. DNA A mistake in DNA replication is called a mutation. Many enzymes are involved in finding and repairing mistakes.

25. RNA O O=P-O OPhosphate Group Group N Nitrogenous base (A, U, G, C ) (A, U, G, C ) CH2 O C1C1 C4C4 C3C3 C2C2 5 Sugar Sugar (ribose) (ribose)

26. RNA Function: obtain information from DNA & synthesizes proteins

27. 3 differences from DNA 1.Single strand instead of double strand 2.Ribose instead of deoxyribose 3.Uracil instead of thymine

28. 3 types of RNA 1.Messenger RNA (mRNA)- copies information from DNA for protein synthesis Codon- 3 base pairs that code for a single amino acid. codon

29. 3 types of RNA 2. Transfer RNA (tRNA)- collects amino acids for protein synthesis Anticodon-a sequence of 3 bases that are complementary base pairs to a codon in the mRNA

30. 3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes

31. Amino Acids Amino acids- the building blocks of protein At least one kind of tRNA is present for each of the 20 amino acids used in protein synthesis.

32. Transcription - mRNA is made from DNA & goes to the ribosome Translation - Proteins are made from the message on the mRNA

33. Transcription In order for cells to make proteins, the DNA code must be transcribed (copied) to mRNA. The mRNA carries the code from the nucleus to the ribosomes.

34. Transcription RNA polymerase binds to DNA (only to promoters- sections that indicate it to bind on DNA molecule) & separates the DNA strands. Uses 1 strand as a template from which nucleotides are assembled into a strand of RNA. Signals (like promoters) tell it to stop when RNA is complete.

36. Translation At the ribosome, amino acids (AA) are linked together to form specific proteins. The amino acid sequence is directed by the mRNA molecule. ribosome Amino acids

37. Translation Begins when mRNA molecule in cytoplasm attaches to ribosome. It begins at AUG (the start codon) which always binds methionine (amino acid). The tRNA contains the anticodon whose bases are complementary to a codon on the mRNA strand. Then another tRNA comes into ribosome and binds the next codon to anticodon.

38. Translation The ribosome will then bind the two amino acids together, using peptide bonds, and breaks the bond between methionine and its tRNA. The tRNA floats away from the ribosome allowing ribosome to bind another tRNA. The ribosome will move along mRNA binding new tRNA molecules and amino acids.

39. Translation Process continues until ribosome reaches one of the three stop codons: –UAA –UAG –UGA Then it releases the formed polypeptide and the mRNA molecule, completing translation.

41. Make A Protein DNA sequence ATG TAC AAC AAG GTA ATT mRNA sequence UAC AUG UUG UUC CAU UAA

42. Make mRNA mRNA sequence UAC AUG UUG UUC CAU UAA tRNA sequence AUG UAC AAC AAG GUA AUU

45. Make mRNA tRNA sequence AUG UAC AAC AAG GUA AUU mRNA sequence UAC AUG UUG UUC CAU UAA Amino Acid sequence met lys asp lys val stop

46. Mutations What causes mutations? –Can occur spontaneously –Can be caused by a mutagen Mutagen: An agent, such as a chemical, ultraviolet light, or a radioactive element, that can induce or increase the frequency of mutation in an organism.

47. Mutations Some mutations can: Have little to no effect Be beneficial (produce organisms that are better suited to their environments) Be deleterious (harmful)

48. Mutations Types of mutations –Point Mutations : involves changes in one or a few nucleotides that occur at a single point in the DNA sequence. Substitutions- one base changed to another Insertions- one base is inserted in the DNA sequence Deletions- one base is removed from the DNA sequence

51. Mutations Example: Sickle Cell Anemia

52. Sickle Cell Mutation Mutation in the haemoglobin gene –Oxygen carrying protein found on red blood cells. Life expectancy is 50- 60 years old!

53. Mutations Types of mutations –Frame Shift Mutations: changes the “reading frame” of the genetic message, so that every codon beyond the point of insertion or deletion is read incorrectly during translation. Ex.: Crohn’s disease

54. Crohn’s Disease Bacterial products activate inflammation in digestive system causing –Diarrhea –Constipation –Cramps Mutation in a gene that produces kininogen protein. Mutation on Chromosome 16 too!

55. InsertionDeletion

56. Huntington’s disease A progressive brain disorder that causes uncontrolled movements, emotional problems, and loss of thinking ability. Mutations in HTT gene causes disease. HTT-produces huntingtin protein. –CAG trinucleotide repeat

57. Mutations Types of mutations –Chromosomal Inversions: an entire section of DNA is reversed. –Ex.: Hemophilia a bleeding disorder

59. DNA Repair A complex system of enzymes, active in the G 2 stage of interphase, serves as a back up to repair damaged DNA before it is dispersed into new cells during mitosis.

60. Mutations Many (most) are neutral and have little or no effect. Polyploidy- a complete set of chromosomes fails to separate during meiosis, can produce gametes with: –3N (Triploid) –4N (Tetraploid) Ex. Polyploid plants are larger and stronger than diplid plants.

62. Gene Regulation Only a fraction of the genes in a cell are expressed at a given time. Expressed gene- a gene that is transcribed into RNA. How does cell decided which will be “expressed” and which will be “silent”?

63. Gene Regulation Certain DNA sequences serve as promoters for DNA-binding proteins to attach and they help to regulate gene expression. There are “regulatory sites” next to the promoter in which the action of these proteins determines whether a gene is turned on or turned off.

64. Gene Regulation Most Eukaryotic genes are controlled individually and have regulatory sequences Why is Gene Regulation Important?

65. Gene Regulation Regulation of gene expression is important in shaping the way a complex organism develops. Differentiation- cells don’t just grow and divide during embryonic development they become specialized in structure and function.

66. Gene Regulation Hox genes- a series of genes that control the differentiation of cells and tissues in the embryo. –A mutation in one of these “master control genes” can completely change the organs that develop in specific parts of the body. –Ex. Fruit fly mutation can replace fly’s antennae with legs growing on its head!

67. Human Genome Project The Human Genome Project is a collaborative effort of scientists around the world to map the entire gene sequence of humans. This information will be useful in detection, prevention, and treatment of many genetic diseases.

68. DNA Technologies DNA technologies allow scientists to identify, study, and modify genes. Forensic identification is an example of the application of DNA technology.

69. Gene Therapy Gene therapy is a technique for correcting defective genes responsible for disease development. Possible cures for: –diabetes –cardiovascular disease –cystic fibrosis –Alzheimer's –Parkinson’s –and many other diseases is possible.

70. Genetic Engineering The human manipulation of the genetic material of a cell. Recombinant DNA- Genetically engineered DNA prepared by splicing genes from one species into the cells of a different species. Such DNA becomes part of the host's genetic makeup and is replicated.

71. Genetic Engineering Genetic engineering techniques are used in a variety of industries, in agriculture, in basic research, and in medicine. This genetically engineered cow resists infections of the udders and can help to increase dairy production.

72. Genetic Engineering There is great potential for the development of useful products through genetic engineering EX., human growth hormone, insulin, and pest- and disease-resistant fruits and vegetables Seedless watermelons are genetically engineered

73. Genetic Engineering We can now grow new body parts and soon donating blood will be a thing of the past, but will we go too far? Photo of a mouse growing a "human ear"