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Two models of nuclear congression have been proposed: the sliding cross-bridge, and the plus end model. In the sliding cross-bridge model, the microtubules run antiparallel to each other for the entire distance between the two pronuclei, forming cross-links to each other, and each attaching to the opposite nucleus at the plus end. This is the ...
Chromatin bridge is a mitotic occurrence that forms when telomeres of sister chromatids fuse together and fail to completely segregate into their respective daughter cells. Because this event is most prevalent during anaphase , the term anaphase bridge is often used as a substitute.
There are two popular and overlapping theories that explain the origins of crossing-over, coming from the different theories on the origin of meiosis.The first theory rests upon the idea that meiosis evolved as another method of DNA repair, and thus crossing-over is a novel way to replace possibly damaged sections of DNA. [9]
The binding of the myosin head to actin is known as a cross-bridge. A molecule, called adenosine triphosphate (ATP) which is produced by an intracellular structure called a mitochondrion, is then used, as a source of energy, to help move the myosin head, carrying the actin. As a result, the actin slides across the myosin filament shortening the ...
The myosin head is the part of the thick myofilament made up of myosin that acts in muscle contraction, by sliding over thin myofilaments of actin.Myosin is the major component of the thick filaments and most myosin molecules are composed of a head, neck, and tail domain; the myosin head binds to thin filamentous actin, and uses ATP hydrolysis to generate force and "walk" along the thin filament.
The outflow of calcium allows the myosin heads access to the actin cross-bridge binding sites, permitting muscle contraction. [ 5 ] Muscle contraction ends when calcium ions are pumped back into the sarcoplasmic reticulum, allowing the contractile apparatus and, thus, muscle cell to relax.
Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion. [1] Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one paralogous DNA sequence converts another.
The structure of DNA-protein complexes can be mapped by photocrosslinking, which is the photoinduced formation of a covalent bond between two macromolecules or between two different parts of one macromolecule. The methodology involves covalently linking a DNA-binding motif of the target sequence-specific DNA-binding protein with a ...