Which technique is used to determine the 3D structure of molecules through X-ray diffraction?

The technique used to determine the three-dimensional structure of molecules through X-ray diffraction is X-ray crystallography. This method involves directing X-rays at a crystallized sample of the molecule. As the X-rays hit the electrons in the molecule, they are scattered in various directions, creating a diffraction pattern. By analyzing this pattern, scientists can infer the arrangement of atoms within the crystal, allowing them to build a detailed 3D model of the molecule’s structure.

X-ray crystallography is particularly powerful because it can reveal the precise locations of atoms and the overall geometry of both small organic compounds and large biomolecules, such as proteins and nucleic acids. The data obtained from X-ray crystallography have provided crucial insights into molecular function and interactions in biological systems.

While the other techniques mentioned—nuclear magnetic resonance, mass spectrometry, and electrophoresis—are valuable for studying various aspects of molecular biology, they do not utilize X-ray diffraction to determine 3D structures. Nuclear magnetic resonance (NMR) is primarily used for determining structures in solution and provides information about the distances and angles between nuclei. Mass spectrometry is a technique for analyzing the mass-to-charge ratio of ions, primarily used for determining molecular weight and composition rather than structure. Electroph