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Great Ideas in Science PROV 301-001 (Spring 2017)

Great Ideas in Science PROV 301-001 (Spring 2017). Prof. Robert M. Hazen Office: East 202 Phone: x 32163 E-mail: rhazen@ciw.edu. Great Ideas in Science: Lecture 12. Great Idea: All living things share the same genetic code. Professor Robert Hazen PROV 301. Key Idea.

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Great Ideas in Science PROV 301-001 (Spring 2017)

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  1. Great Ideas in SciencePROV 301-001(Spring 2017) Prof. Robert M. Hazen Office: East 202 Phone: x 32163 E-mail: rhazen@ciw.edu

  2. Great Ideas in Science:Lecture 12 Great Idea: All living things share the same genetic code. Professor Robert Hazen PROV 301

  3. Key Idea All living things share the same genetic code. 1. DNA carries the genetic message. 2. Messenger RNA copies the DNA. 3. Transfer RNA holds an amino acid. 4. The ribosome assembles a protein.

  4. Classical Genetics Gregor Mendel used pea plants to discover three laws of inheritance. 1. Genes exist. 2. Each parent contributes half. 3. Some traits are dominant and some are recessive traits.

  5. Cellular Genetics • Chromosomes provide genetic clues. • Humans have 23 pairs of chromosomes. • In mitosis one cell becomes two: • 2 daughter cells are the same as the parent. • Most cells divide by mitosis in your body. • In meiosis one cell becomes 4 gametes. • Crossing-over shuffles genes from parents. • Recombination makes every gamete unique.

  6. Mitosis • Simple cell division: One cell becomes two. • A 3-step process: First copy the chromosomes. Second, separate chromosomes. Third, divide the cell into two.

  7. Meiosis • Chromosome crossover mixes up genes. • 1 cell forms 4 gametes: Gametes are genetically unique. They have ½ normal chromosomes

  8. Nucleotides: The Building Blocks of Nucleic Acids Nucleotides are made from three molecules: 1. Sugar DNA: deoxyribose RNA: ribose 2. Phosphate ion 3. Base Adenine (A) Guanine (G) Cytosine (C) Thymine (T)

  9. DNA’s Double Helix

  10. DNA Base Pairing A—T C—G

  11. The Replication of DNA • DNA replication occurs before mitosis & meiosis. • The process is simple: • The DNA double helix splits down the middle. • New bases bond to exposed bases. • This results in two identical DNA strands.

  12. The Replication of DNA • DNA replication occurs before mitosis & meiosis. • The process is simple: • The DNA double helix splits down the middle. • New bases bond to exposed bases. • This results in two identical DNA strands.

  13. The Replication of DNA • DNA replication occurs before mitosis & meiosis. • The process is simple: • The DNA double helix splits down the middle. • New bases bond to exposed bases. • This results in two identical DNA strands.

  14. How Does DNA Make Protein? • Chromosomes (DNA) • Carry the genetic message • Messenger RNA • Copies the genetic message • Transfer RNA • Holds an amino acid • The Ribosome • Assembles a protein

  15. Synthesis of ProteinsStep 1: Transcription of DNAMessenger RNA (mRNA)

  16. Synthesis of ProteinsStep 2: Match tRNA to mRNATransfer RNA (tRNA)

  17. The Ribosome

  18. The Genetic Code

  19. Protein Synthesis Summary

  20. DNA & RNA Vocabulary • Nucleotide = one genetic letter – phosphate-sugar-base (A, T, C or G) • Codon = one 3-letter genetic word that defines an amino acid • Gene = the recipe for one protein, typically with >100 genetic words • Chromosome = a genetic cookbook with thousands of protein recipes • Genome = all of the genetic material of an organism (23 volumes for humans)

  21. From DNA to ProteinStep 1: DNA  mRNA

  22. From DNA to ProteinmRNA  tRNA  Amino Acid

  23. From DNA to ProteinStep 2: mRNA locks onto the ribosome

  24. From DNA to ProteinStep 2: mRNA locks onto the ribosome

  25. From DNA to ProteinStep 3: tRNA matches mRNA

  26. From DNA to ProteinStep 4: Amino acids link up

  27. From DNA to ProteinStep 4: Amino acids link up

  28. Genetics – Key Concepts • Human genome project • Viruses • DNA Fingerprinting (PCR) • Genetic Engineering Microbes Plants Animals/People • Cancer • Ethics in genetics

  29. Human Genome Project(Our DNA) We all have 23 pairs of chromosomes with: ~ 25,000 genes (each codes for a protein) ~ 3,000,000,000 base pairs (these are the rungs of the DNA ladder)

  30. Human Genome ProjectMapping Mapping = locating the genes

  31. Human Genome ProjectSequencing Sequencing = exact sequence of A,T,C, & G

  32. Human Genome ProjectOther Organisms Mouse, Rat, Rabbit, Cat, Dog Chimpanzee, Elephant, Whale, Zebrafish Frog, Fly, Flatworm Several plants Yeast Hundreds of microbes (pathogens) Thousands of viruses Mammoth!!!

  33. Unanswered Question:Why Are Genes Expressed? All your cells contain the same genes. But not all cells have same the function. Therefore, some process must turn genes on and off. How and why are certain genes activated?

  34. 2. Viruses Ebola HIV SARS Swine Flu

  35. 2. Viruses

  36. 2. VirusesWhat is a Virus? • A virus is a loop of genetic material (DNA or RNA) wrapped in proteins. • It “infects” a cell by using the universal genetic code.

  37. 2. Viruses Viruses are not alive and they cannot reproduce on their own. The structure is a short piece of DNA or RNA surrounded by a protein coating. How it works: It is taken into the cell. It can takes over the cell to produce more copies. It may kill the cell, or it may hide in the cell.

  38. Viral Epidemics • Treatment of Viruses: Most medications treat the symptoms, not the virus. Vaccinations are often extremely effective. • Viruses evolve rapidly because the DNA/RNA easily mutates (that is, it changes).

  39. 3. DNA Fingerprinting (PCR)

  40. 3. DNA Fingerprinting • DNA fingerprinting is based on each person’s unique DNA. It can be used to identify victims, criminals, or parents/children. • The process involves analyzing sections of DNA and comparing with a known person of interest.

  41. 3. DNA Fingerprinting (PCR) Step 4: Repeat with 2 strands of DNA.

  42. 3. DNA Fingerprinting (PCR)

  43. 4. Genetic Engineering

  44. 4. Genetic Engineering • Genetic engineering can involve inserting foreign genes or altering existing genes. • The techniques commonly involve cutting and splicing pieces of DNA. • Examples include insulin, agriculture, and security.

  45. Stem Cells • An embryo’s first cells can be anything. • Later cells differentiate. • As the embryo grows, some genes are turned on and other genes are turned off. • A “stem cell” reproduces without differentiation.

  46. Cloning: Engineering an identical individual

  47. 4. Gene Therapy

  48. 4. Gene Therapy Gene therapy involves replacing defective genes with healthy one. “In vivo” therapies use injections. “In vitro” therapies use testtubes. Among many problems, the genes are inserted randomly, so often no proteins are made. Therapeutic viruses offer an important option.

  49. 4. Viral Gene Therapy

  50. 5. Cancer

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