Crowding effects on the segregation of cylindrically confined ring polymers
Kerry, Deanna Rita-Mae
Honours
2017
Polson, James
Bachelor of Science
Faculty of Science. Honours in Physics.
Physics
University of Prince Edward Island
Charlottetown, PE
In the cell cycle, chromosome segregation occurs during anaphase, the process where original and replicated chromosomes move towards opposite sides of the cell to await cell division. This process is well-described and understood in eukaryotic cells, but this is not true for bacteria. Bacteria do not have the structures to facilitate chromosome segregation that are present in eukaryotes. Some researchers have suggested that instead of being facilitated by specific structures, bacterial Show moreIn the cell cycle, chromosome segregation occurs during anaphase, the process where original and replicated chromosomes move towards opposite sides of the cell to await cell division. This process is well-described and understood in eukaryotic cells, but this is not true for bacteria. Bacteria do not have the structures to facilitate chromosome segregation that are present in eukaryotes. Some researchers have suggested that instead of being facilitated by specific structures, bacterial chromosome segregation is driven largely by entropy. We modeled bacterial chromosomes as hard-sphere ring polymers and studied systems of two polymers in cylindrical confinement of both finite and infinite length. The polymers have lower entropy when they overlap along the cylinder than when they are completely segregated, which means that they segregate spontaneously from one another in order to achieve equilibrium (where in this type of system, entropy is maximized). Because up to 30% of the volume of certain bacterial cells can be occupied by macromolecular crowders, it was important to consider the effects of crowding agents on our system. A previous study observed that the free energy barrier of segregating polymers decreases with increasing crowding agent density, and we were able to reproduce this trend for polymers of different size, cylinder diameter, and crowding agent density. We also studied the effects of crowding on polymers confined to a cylinder of finite length and observed that the free energy barrier increases with increasing crowding agent density, a trend that was opposite to observations from the infinitely long cylinder. Show less
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