Chromatin, chromosomes and genomes

    Cards (27)

    • What is the diameter of an average human nucleus?
      10 µm
    • How long is the DNA in each cell?
      About 2 m
    • What are the two types of chromatin and their characteristics?
      • Euchromatin: More open, allows gene transcription
      • Heterochromatin: Tightly packaged, less accessible
    • Why is DNA packaged within the nucleus?
      To fit, organize, and protect it
    • What is the structure of the nucleosome?
      • Composed of DNA wrapped around histones
      • Forms the basic unit of chromatin
    • What is the size of the fiber formed by nucleosomes?
      11 nm
    • Describe the Zig-zag model of the 30 nm fiber.
      • Nucleosomes form a tetra-nucleosome
      • Stacked like coins
    • What is the alternative model to the Zig-zag model of chromatin fibers?
      • Solenoid Model
      • Six nucleosomes per twist of coil
    • What is the size of the chromonema formed from the 30 nm fiber?
      120 nm
    • What are the functions of DNA packaging?
      • Fits within the nucleus
      • Allows unpacking for transcription and repair
      • Protects DNA from mutagens
    • What are telomeres and centromeres primarily composed of?
      Heterochromatin
    • What is the significance of protecting DNA through packaging?
      It prevents attacks from mutagens
    • How does euchromatin differ from heterochromatin in terms of gene transcription?
      Euchromatin allows transcription; heterochromatin does not
    • If a cell's DNA is uncoiled, what risks does it face?

      It can be attacked by mutagens
    • What is the total number of base pairs in the human genome?
      3,200,000,000 base pairs
    • What is the smallest genome size recorded and in which organism?
      160,000 bp in Carsonella ruddii
    • Which organism has the largest animal genome?
      Australian lungfish
    • Is genome size linked to organism complexity?
      No, genome size is not linked to complexity
    • What are the sex chromosome configurations in humans and birds?
      • Humans: XX (females), XY (males)
      • Birds: ZZ (males), ZW (females)
    • How do turtles determine sex?
      Through environmental cues like temperature
    • What is the term for organisms with two identical sex chromosomes?
      Homogametic
    • What is the term for organisms with two different sex chromosomes?
      Heterogametic
    • What are the main differences between prokaryotic and eukaryotic genomes?
      • Prokaryotic: Circular, compact, common operons
      • Eukaryotic: Linear, mostly introns, large genes
    • What types of genomes can viruses have?
      DNA or RNA
    • How do viruses replicate?
      They need host machinery to replicate
    • What are prions?
      Misfolded proteins that infect tissues
    • What disease is associated with prions?
      Creutzfeldt-Jakob disease