What is the Longest Molecule Ever Discovered?

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Discussion Overview

The discussion centers around the concept of the longest molecule ever discovered, exploring various definitions and examples of what constitutes a molecule. Participants debate the lengths of different types of molecules and the criteria that classify them, including considerations of polymers and macromolecules.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants suggest various examples of long molecules, including DNA, carbon nanotubes, and polymers, while questioning the definitions of what counts as a molecule.
  • There is a discussion about the lengths of carbohydrates, proteins, lipids, and nucleic acids, with some participants asserting that proteins and lipids are generally smaller than the others.
  • A participant mentions a professor's claim about the interconnectedness of water molecules across vast distances, raising questions about how such a claim could be proven.
  • Some participants question the distinction between crystalline solids or metals and molecules, suggesting that the definitions may be arbitrary.
  • There is speculation about the potential for creating very long polymers and whether there are practical limits to their length due to thermodynamic fluctuations.
  • One participant cites a specific example of a large hollow cage molecule made from 1000 atoms and discusses the classification of polymers as molecules.
  • Another participant challenges the classification of polymers, suggesting that they should not be considered molecules, referencing IUPAC definitions.

Areas of Agreement / Disagreement

Participants express differing views on what constitutes a molecule, particularly regarding the classification of polymers. There is no consensus on the definitions or examples presented, and the discussion remains unresolved.

Contextual Notes

Limitations include varying definitions of molecules, the ambiguity surrounding the classification of polymers, and the lack of consensus on the implications of molecular length and structure.

mollwollfumble
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TL;DR
Longest DNA, nanotube, polymer, silk, nylon, glass, wire
What is the longest molecule? Are we talking about of order of magnitude:
  • 1 metre, eg. DNA, carbon nanotube, polyethylene (UHMWPE)?
  • 1 kilometre, eg. silk strand, monofilament nylon?
  • 100 to 1,000 km, eg. steel wire for suspension bridge, copper wire, optical glass fibre?
  • 12,700 km, covalent bonding connecting the whole of the Earth's crust?
 
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What have you found so far?

Why do you think things you listed count as molecules? What is a molecule?
 
Carbohydrates, Proteins, Lipids, Nucleic acid are Four Large Molecules
 
Seconding Borek's question: you should first learn what defines a molecule. That will make the answer to your quiz quite simple.
 
naresh123 said:
Carbohydrates, Proteins, Lipids, Nucleic acid are Four Large Molecules
Carbohydrates and nucleic acids can each by up to of order two metres long. Aren't proteins and lipids very much smaller?
 
mollwollfumble said:
Aren't proteins and lipids very much smaller?
I think only lipids falls in micromolecules and proteins are macromolecules.
 
I had a professor that said it was the ocean since water is always in the process of taking/borrowing hydrogens. He said that touching a water molecule along the shore here in North America had an effect on a water molecule in Antartica. I always wondered how he would prove something like that...
 
What is the distinction between a crystalline solid (or a metal) and a molecule? There are individual atoms and variously stable agglutinations of atoms: to me the other designations seem arbitrary (and possibly capricious!)
 
An nth-length alcohol or something similar would probably be the longest.
 
  • #10
Can't one make certain polymers as long as is desired? Maybe thermodynamic fluctuations produce a practical limit?? Seems like you just add another monomer.
 
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  • #11
hutchphd said:
Can't one make certain polymers as long as is desired? Maybe thermodynamic fluctuations produce a practical limit?? Seems like you just add another monomer.

That was my understanding. You can just keep stitching carbon atoms on the end in a DNA-Like structure and keep going forever. I wonder if a degenerate star counts as being a molecule? I suppose it has to be pure chemical forces and not gravity holding it together.
 
  • #12
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