In the nucleus of eukaryotic cells, DNA molecules are very long, linear and associated with proteins called histones; together they form a chromosome
In eukaryotic cells, DNA wraps around proteins called histones to form a chromosome. Each DNA molecule is very long and linear — it has two free ends.
Real World
Cancer chemotherapy drugs such as etoposide target topoisomerase enzymes that manage DNA coiling during replication; because human DNA is so long and tightly histone-wound, disrupting this process selectively kills rapidly dividing tumour cells.
Exam Focus
Always specify that eukaryotic DNA is associated with histones to form chromatin — just saying 'wrapped around proteins' without naming histones may not earn the mark.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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