Practice question · Multiple choice
Chromatin packing is dynamic rather than fixed. Why must a differentiated cell continuously shift specific regions of DNA between euchromatin and heterochromatin?
Hints
- What physical constraint does dense nucleosome packing impose on the molecular machinery that reads DNA?
- How does a non-dividing cell adjust which proteins it synthesises in response to its environment?
Show the answer
A. To enable selective access to genes required for changing metabolic demands
Why
Packing regulates transcription by physical accessibility; silent regions are condensed, not permanently locked away. Structural support relies on the lamina rather than chromatin state, while replication and ribosome assembly involve distinct, specialised nuclear subdomains.
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More questions on The Cell Nucleus
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- Complete the account of chromatin states.