What causes knots and stress when untwisting ropes?

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SUMMARY

The discussion centers on the phenomenon of torsional stress and knot formation when untwisting ropes, drawing parallels to the role of topoisomerases in DNA replication. Torsional stress arises from the unwinding of coiled strands, leading to the development of supercoils and knots that hinder further uncoiling. The original twist in the rope is often in the opposite direction from the larger twist, contributing to the complexity of the untwisting process. Understanding these mechanics is crucial for both practical applications in rope handling and theoretical insights in molecular biology.

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  • Understanding of torsional stress in physical materials
  • Familiarity with the concept of supercoiling in DNA
  • Knowledge of topoisomerases and their function in DNA replication
  • Basic principles of knot theory and its applications
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  • Research the mechanics of torsional stress in materials science
  • Study the role of topoisomerases in molecular biology, specifically in DNA replication
  • Explore knot theory and its relevance to physical and biological systems
  • Investigate practical techniques for untwisting ropes without causing knots
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This discussion is beneficial for physicists, biologists, material scientists, and anyone involved in practical applications of rope handling or studying molecular structures.

Aurelius120
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[Mentor Note -- thread moved from the schoolwork forums to GD as it seems like a more general question]

Homework Statement:: Topoisomerases help in relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix (Topoisomerases are enzymes that participate in the over winding or underwinding of DNA).
The strain is same as caused when two ropes twisted around each other are untwisted from both ends.
Relevant Equations:: NA

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As shown in the image the ropes develop supercoils on being unwound.
The knots caused due to untwisting develops tension enough to make it impossible to uncoil the rope further.

My question is :

What causes such unwanted stress(called torisonal stress maybe) and these knots?
Why does it happen only with coiled strands of rope?

All research has failed at providing the right solution to this problem(or even an incentive)
 
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I would guess that in untwisting the rope you are adding twist to the individual strands. I bet it doesn't happen if you comb it, i.e. allow the individual strands to twist freely.

It looks to me like the original twist in the rope is in the opposite direction from the larger twist shown.
 

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