Bio 273 Chapter 12

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  1. Human cells contain how many DNA?
    6 billion base pair
  2. DNA structure
    • Primary - Nucleotide sequence
    • Secondary - Double stranded helix
    • Tertiary - Higher Order Folding (Supercoiling)
  3. Overrotated molecules of DNA
    Positive Supercoiling
  4. Underrotated molecules of DNA
    Negative Supercoiling
  5. Enzyme that adds or remove rotations by temporarily breaking nucleotide strands, rotating ends and rejoining broken ends
  6. Supercoiling advantages:
    • Easier during replication and transcription
    • Can be packed into smaller spaces
  7. Unersgoes normal condensation and decondensation
  8. Remains highly condensed throughout cell cycle.
  9. Type of Chromatin that exists at telomeres and centromeres
  10. Name 5 chromatin histones
    • H1
    • H2A
    • H2B
    • H3
    • H3
  11. DNA wrapped 2 x around octamer histone proteins
    • Nucleosome
    • 145 bp
  12. Octomer histone proteins
    • 2x each
    • H2A
    • H2B
    • H3
    • H4
  13. Chromatosome
    Nucleosome plus H1 histone
  14. Localized swelling of chromosome, showing active transcription
    Chromosomal puffs
  15. Gian chromosomes, unusual, due to replication without cell divisions
    Polytene chromosomes
  16. Stable alterations in chromatin structure (methylation) that can be passed ont o cells or individual organisms. They do not alter DNA sequence, can be reversed and often influenced by environmental factors.
    Epigenetic Genes
  17. Contain centromeric sequences that are bidnign sites for kinetochore
  18. "End Caps" that keep DNA from degrading usually consist of repeating units of A/T followed by G/C (End of chromosome)
  19. Binds to telomeres overhang to prevent repair
  20. Amount of DNA per cell
  21. During Denaturation which requires more heat?
    G/C or A/T why?
    G/C requires more heat because it has 3 hydrogen bonds connecting them versus A/T only has 2 h bonds
  22. Annealing of 2 DNA from different sources
  23. DNA sequences that are only repeated once or at the most a few times. Make up 25-50% of protein encoding genes
    Unique Sequence DNA
  24. Repeating DNA. 150-300 bp
    Moderately Repeating DNA
  25. Tandem Repeating Sequences
    Repetitive sequences, one after another
  26. Interspersed Repetitive DNA
    Include LINE, SINE
    Scattered throughout genome
  27. AKA Satellite DNA, less than 10bp in lenght
    no known function
    Highly repetivie DNA
  28. 3-12 bp in length added on both sides of transposable elements
    short flanking direct repeats
  29. mobile DNA sequences able to insert at many different locations
    transposable elements
  30. 9-40 bp inverted DNA sequences, complements of each other. Exist at many ends of transpoable elements.
    terminal inverted repeates
  31. the movement of a transposalbe element from one location to another
  32. transposition - 3 steps
    • staggered breaks
    • transposable element joined to single stranded ends of target DNA
    • DNA replicated at single strand gaps
  33. some transposable elements tranpose as DNA
    DNA transposons
  34. elements that transpose through a RNA intermediate
  35. Copy and Paste transposition
    Replicative transposition
  36. Cut and Paste transposition
    Non-replicative transposition
Card Set
Bio 273 Chapter 12
Bio 273 Chapter 12
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