Human chromosomes are linear dsDNA and they often show topological constraints, particularly during DNA replication and transcription. Why do the chromosomal DNA would have topological constraints?
A. Multitudes of H bonding between bases make long dsDNA quite stable
B. Protein-DNA interactions may cause changes in the DNA topology
C. Chromosomes circularize during replication and transcription
D. Because of two of these options
E. Because all of these options
answer: B
the chromosomal DNA would have topological constraints because of the presence of Protein-DNA interactions that may cause changes in the DNA topology.
topological constrains is because of the supercoiling of DNA , supercoiling represents a coiling of DNA double helix upon itself. it can occur in covalently closed circular DNA and also in linear DNAs that are topologically contrained by being complexed with proteins. in linear DNAs if the ends of the molecules are fixed then any rotational freedom that the two backbones might have about one another is removed and as a result any local twisting or untwisting will cause a strain on the structure .
Human chromosomes are linear dsDNA and they often show topological constraints, particularly during DNA replication and...
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