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Chromosomes and DNA replication

Cell biology • Cell division

Key concepts

What you'll likely be quizzed about

  • Chromosomes consist of long strands of DNA wrapped around histone proteins forming chromatin.
  • Further folding results in a compact structure visible during cell division.
  • Each chromosome includes key regions: the centromere and two arms.
  • In diploid cells, chromosomes appear in matched pairs, allowing for two alleles of each gene, one from each parent.
  • During interphase, chromosomes are less condensed, allowing access for transcription and replication.
  • Once DNA replication occurs, each chromosome turns into two identical sister chromatids joined at the centromere, which facilitates their separation during mitosis.

Flashcards

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What prevents most replication errors?

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Proofreading and repair enzymes correct mismatches, reducing mutations during DNA replication.

Key notes

Important points to keep in mind

Chromosomes are DNA packaged with proteins to control access and compaction.

Complementary base pairing provides the template mechanism for precise DNA copying.

DNA replication creates sister chromatids; chromatids separate in mitosis to form identical daughter cells.

Replication fidelity depends on proofreading and repair; mutagens increase the risk of errors.

Condensing chromosomes before mitosis ensures reliable mechanical separation of genetic material.

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