Bio 214 Chapter 5

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  1. what is the bonds btwn base portions of nucleotides in DNA?
  2. backbone of DNA
  3. how many base pairs per helical turn
  4. what on DNA differs organisms?
    nucleotide sequences
  5. the 20 letter amino acid alphabet spelt out with 4 letter nucleotides
    genetic code
  6. nucleotide sequence of gene transcribed and then translated
    gene expression
  7. what is the DNA molecules packaged into?
  8. how many different types of chromosomes is in a human nucleus?
    23 or 24 for Y chromosome
  9. DNA + proteins that fold and pack
  10. what type of cells are sperm and eggs?
    germ cells
  11. maternal and paternal chromosomes of a pair
    homologous chromosomes(homologs)
  12. whats the only nonhomologous chromosome pairs
    sex chromosomes
  13. chromosomes distinguished with different fluorescent dyes
    DNA hybridization
  14. ordered display of all 46 human chromosomes
  15. segment of DNA that contains the instructions for making a protein or RNA molecule
  16. total genetic information in all chromosomes in a cell
  17. large excess of interspersed DNA
    junk DNA
  18. when chromosomes are duplicated
  19. when chromosomes are distributed or segregated to two daughter nuclei
  20. chromosomes are extended
  21. type of nucleotide sequence that acts as a begin site for DNA replication
    replication origin
  22. * located at each end of chromosome
    * contain repeated nucleotide sequence required for chromosomes to be replicated
    * cap DNA ends
  23. allows duplicated chromosomes to be separated during M phase
  24. stage DNA coils up, compacts into a structure of chromosomes
    • M phase
    • mitotic chromosomes
  25. two places chromosomes tend to attached to
    • nuclear envelope
    • nuclear lamina
  26. the two DNA forming chromosomes classes
    histones and nonhistones
  27. Histone responsible for the first and most fundamental level of chromatin packing
  28. series of "beads on the string" string being DNA and beads being
    nucleosome core particle, DNA wound around a core of proteins formed from histones
  29. DNA wound around a core of proteins formed from histones
    nucleosome core particle
  30. enzymes that break down DNA by cutting phosphodiester bonds between nucleotides
  31. exposed DNA between core particles
    linker DNA
  32. nucleosome core particle + adjacent DNA linkers
  33. what helps the histones bind tightly to the negatively charged sugar-phosphate backbone of DNA?
    positively charged amino acids(lysine and arginine)
  34. nucleosome core particle structure
    • 2 of each histones
    • DNA, 147 nucleotide pairs long
    • histone octamer
    • linker DNA
  35. long, unstructured N-terminal amino acid
    • histone tail
    • each histone has one
  36. what controls many aspects of chromatin structure and how
    histone tails, subjected to several types of reversible, covalent chemical modifications
  37. histone that changes the path the DNA takes as it exits the nucleosome core-to form a more condensed chromatin fiber
    linker histone/H1
  38. levels of chromatin fiber folding
    • folded into loops
    • loops condensed-interphase chromosome
    • compact string of loops-mitotic chromosome
  39. what allows access to DNA
    changes in nucleosome structure
  40. protein machines that use energy of ATP hydrolysis to change position of DNA wrapped around nucleosomes
    chromatin-remodeling complexes
  41. what is attached to both the histone octamer and DNA which controls access to DNA and remaining inactive during mitosis
    chromatin-remodeling complexes
  42. what can be added or removed to histone tails that would alter chromatin structure
    • acetyl
    • phosphate
    • methyl groups
  43. this can reduce the affinity of tail for adjacent nucleosomes thereby loosening chromatin structure
    acetylation of lysine
  44. rxns from proteins on docking site of histone tails
    • promote chromatin condensation
    • decondense & facilitate access to DNA
    • indicates newly replicated chromatin
    • indicates genes in stretch of chromatin that should be expressed
    • indicate nearby genes that need to be silenced
  45. 2 interphase chromatins
    • heterochromatin-most highly condensed
    • euchromatin
  46. what happens when histone tail modification attracts a set of heterochromatin-specific proteins?
    • heterochromatin spreads out
    • causes a wave of condensed chromatin to propagate
    • propagation continues spread until barrier DNA sequence
  47. where in a chromatin does DNA not contain genes and why
    • heterochromatin
    • bc its so compact genes usually fail to be expressed
  48. 2 alternative RNA's we're learning about
    • Small interfering RNA
    • MicroRNA
  49. quicker alternative to feedback loops
  50. shorten mRNA life span by adding extra sequences to which prime end?
  51. what type of specialized cell is most embryos composed of?
    iPS cells
  52. Part of DNA that expresses specific tissues
    transcription factors on Enhancer region
  53. What do transfactors recruit?
    • HAT-Histone acetylases-loosening chromatin
    • HDAC-histone deacetylases-compacting chromatin
  54. Cis vs. trans
    • postivie Cis elements are bound by trans factors called activators
    • Negative Cis elements bound by trans factors called repressors
  55. 2 steps at pre-transcription
    • closed chromatin
    • chromatin remodeling
  56. 1 thing that happens at transcription
    chromatin opens
  57. 3 things at post-transcription/pre-translation
    • hetereonuclear
    • mRNA
    • cytoplasmic mRNA
  58. entire stretch of DNA that includes operators, promoters, and genes that they control in bacteria
  59. operon that is usually on until bonded w/molecule from negative feedback
    • repressible operon
    • trp
  60. operon that is usually off, for catabolic pathways
    what turns it on and example
    • inducible operon
    • inducer inactivates repressor
    • Lac operon
    • positive feedback
  61. stimulatory protein that positively controls operons
    • catabolite activator protein
    • activator of transcription
  62. When is CAP (catabolite activator protein) activated?
    • glucose is scared
    • activated by binding with cAMP
  63. RXN that happens when CAP is activated by cAMP
    • lac operon increases affinity of RNA polymerase, accelerates transcription
    • when glucose levels increased, CAP leaves LAC, resumes normal activity
  64. 2 ways a cell can regulate the activity of enzymes
    • feedback inhibition
    • gene regulation
  65. what controls gene expression in bacteria?
    operon model
  66. how does feedback pathways work?
    final end product binds to block rest of steps
Card Set
Bio 214 Chapter 5
chap 5
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