Genetics Exam 1

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Genetics Exam 1
2012-08-24 15:57:01
Genetics BY210

Fall 2012
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  1. Gregor Mendel
    1866 - Paper on inheritance in peas
  2. Sutton
    1902 (Sutton) Genes located on chromosomes
  3. Watson and Crick
    1953 - DNA double helix
  4. Kary Mullis
    1986 - Polymerase Chain Reaction
  5. 1990
    Gene Therapy
  6. 1996
    Dolly the Cloned Sheep
  7. 1995-2005
    Several genomes completely sequenced
  8. Biochemical reactions require
  9. Gene products (examples and necessary)
    • Enzymes are gene products
    • Gene products are necessary for metabolism and growth

    Many genetic diseases involve defective enzymes
  10. Fruit Fly
    Drosophila melanogaster
  11. Bacterium
    Escherichia coli
  12. Roundworm
    Caenorhabditis elegans
  13. Thale Cress Plant
    Arabidopsis thaliana
  14. House Mouse
    Mus musculus
  15. Baker's Yeast
    Saccharomyces cerevisiae
  16. Why are model organisms used in laboratories?
    • Short generation time
    • Manageable numbers of progeny
    • Easily adaptable to the lab
    • Inexpensive to maintain
  17. DNA structure
    Deoxyribonucleic Acid - Double Helix
  18. Primary structure
    Nucleotide sequence
  19. Secondary structure
    Alpha helix
  20. Tertiary structure
    Higher order folding
  21. Length of E. coli DNA
    4.64X10^6 base pairs
  22. Length of H. sapiens DNA
    6X10^9 base pairs
  23. Width of DNA double helix
    2 nm
  24. Number of base pairs wrapped around histone
  25. Number of times DNA wraps around histone
  26. Amount of linker DNA
    30-50 base pairs
  27. Histone proteins
    • Structural
    • H1 & H5 -  Linker
    • H2A, H2B, H3, and H4 - Core
    • Strongly alkaline proteins
    • Only in Eukaryotic cells
    • Form spools around which DNA winds
  28. Nucleosomes
    Histones + DNA
  29. Chromatosome
    Nucleosome with one bound linker histone
  30. Where does H1 attach to the core particle?
    Where the DNA joins and leaves
  31. Solenoid
    • 30 nm fiber of chromatin
    • Helical winding of at least five nucleosome strands
    • Six connected loops form a ROSETTE
  32. Chromatid
    One of two idenitcal copies of DNA making up a duplicated chromosome
  33. Centromere
    • Join sister chromatids
    • Help control the cell cycle by inhibiting anaphase until all the spindles are attached
    • Kinetochore proteins bind to them
  34. Telomeres
    • Serve as caps that stabilize chromosome ends
    • Provide a means for replicating the ends of chromosomes
    • Characteristic Nucleotide sequences
  35. Useful properties to describe chromosomes:
    • Size
    • Number
    • Position of centromere
    • Nucleolar organizers number and position
    • Chromomere patterns
    • Heterochromatin patterns
    • Banding patterns
  36. Types of Chromosomes
    • Metacentric
    • Submetacentric
    • Acrocentric
    • Telocentric
  37. Are X and Y homozygous?
  38. Heterochromatin
    • Highly condensed
    • Transcriptionally inactive
    • Dark when stained
  39. Euchromatin
    • Lightly packed
    • Usually under active transcription
    • Light when stained
  40. Banding patterns
    Transverse bands along the length of the chromosomes
  41. G-bands
    • Made visible with Giemsa stain
    • Rich in A-T bonds
  42. R-bands
    • Visible with reversed Giemsa stain
    • rich in G-C bonds
  43. Other types of stains
    • C- constitutive heterochromatin
    • T- telomeres
    • NOR- nucleolar organizer
  44. Nucleolar organizer
    A chromosomal around which the nucleolus forms, a site of tandem repeats of the rRNA genes.
  45. Nucleolus
    visible region in nucleus where portions of the ribosomes (rRNA) are being assembled.
  46. Chromomere patterns
    • Little thickenings along the chromosome, easily viewed during prophase of mitosis and meiosis.
    • Especially large chromomeers are called "knobs."
    • Unkown function
  47. Cell cycle
    • Series of events that takes place in a cell leading to its division
    • Two periods: interphase and mitosis
  48. Interphase
    Time where the cell grows and duplicates DNA
  49. Mitosis
    Cell splits itself into two daughter cells
  50. Three sub phases of Interphase
    G1, S, G2
  51. G1
    Cell grows and carries out normal activities
  52. S
    Cell replicates its chromosomes (DNA)
  53. G2
    Cell replicates its organelles and prepares for division
  54. Is interphasal DNA uncoiled?
    • Yes!
    • In G1 or G2- Chromatin is NOT condensed - chromosomes are long strands of chromatin.
    • S- DNA replication occurs
  55. G0 Phase
    • Gap Zero
    • Period in the cell cycle where cells exist in a quiescent state
    • Typical cells that rarely divide (neurons, heart muscles)
  56. Cell cycle check points
    • Used by the cell to monitor and regulate the progress of the cell cycle
    • Prevent cell cycle progression at specific points, allowing verification of necessary phase processes and replair of DNA damage
  57. p53
    • When malfunctioning is responsible for more than half of cancer cells
    • Plays an important role at both G1/S and G2/M checkpoints
  58. G1/S Checkpoint
    Key decision (restriction point): whether the cell should divide, delay division, or enter a resting stage.
  59. G2/M Checkpoint
    • Check for potential DNA damage to ensure cell is ready for Mitosis
    • Postreplication checkpoint