Medida da força entrópica de uma molécula de DNA

• Ano de defesa: 2001
• Autor(a) principal: Rodrigo teixeira Santos Freire
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Física; Biofisica; Entropia Moleculas; Biopolimeros; Moleculas
• Link de acesso: http://hdl.handle.net/1843/BUBD-AF4M2K

This work combines optical tweezer, videomicroscopy and photon correlation techniques in order to study the entropic elastic behaviour of single A-fage DNA molecules. A DNA molecule is attached by one end to the surface of a coverslip and by the other to the a 3m polystyrene bead. The optical trapping of this bead enables the manipulation and stretching of the DNA molecule. The photon correlation technique is used to measure the trapping force constant. By measuring also the displacement of the bead relative to its equilibrium position in the trapping potential well, it is possible to determine the force DNA exerts as a function of its extension. This force is theoretically described by the Worm-Like Chain (WLC) model and the persistence length of the DNA molecule is obtained.