Chromosomes and chromatin Transitional Reasoning Practice

Questions

1. 1.

   A research team investigating eukaryotic gene regulation analyzes nuclear material extracted at different stages of the cell cycle. They find that interphase DNA exists largely as dispersed, accessible chromatin that permits active transcription, whereas during mitosis, the genome condenses into discrete, tightly packed chromosomes accompanied by a global shutdown of RNA synthesis. Based on this structural and functional transition, which of the following best explains why eukaryotic cells compact chromatin into dense chromosomes during cell division?

   • A) Condensation prevents replication errors by covalently locking histone octamers permanently onto the phosphodiester backbone.
   • B) Dispersed chromatin cannot interact with DNA polymerases, so maximum compaction is required before DNA duplication can occur.
   • C) Histone proteins detach entirely during mitosis, allowing bare DNA strands to pack tightly without electrostatic repulsion.
   • D) Extreme packaging protects extended DNA fibers from tangling and mechanical shearing during sister chromatid segregation, despite transiently halting transcription.

Answers and step-by-step solutions appear after you finish the test.