Structural Biophysics – MCQs 50 Score: 0 Attempted: 0/50 Subscribe 1. Structural biophysics primarily studies: (A) Motion of planets (B) Structure and function of biological macromolecules (C) Radiation therapy in medicine (D) Blood pressure regulation 2. The primary structural technique that uses X-ray diffraction is: (A) MRI (B) PET (C) X-ray crystallography (D) Ultrasound 3. NMR spectroscopy provides structural information based on: (A) Nuclear magnetic resonance of atomic nuclei (B) X-ray scattering (C) Electron tunneling (D) Ultrasound reflection 4. The structural resolution of cryo-electron microscopy (cryo-EM) can reach: (A) Millimeter scale (B) Nanometer to near-atomic scale (C) Kilometer scale (D) Centimeter scale 5. Protein secondary structures are commonly identified by: (A) Circular dichroism spectroscopy (B) Ultrasound scans (C) PET imaging (D) Radiation therapy 6. The α-helix structure of proteins was proposed by: (A) Watson and Crick (B) Linus Pauling (C) Francis Crick (D) Rosalind Franklin 7. The β-sheet structure in proteins is stabilized by: (A) Disulfide bonds (B) Hydrogen bonds between backbone atoms (C) Covalent crosslinks (D) Ionic bonds 8. The quaternary structure of proteins refers to: (A) Atomic orbitals (B) Interaction between multiple protein subunits (C) DNA double helix formation (D) Energy states of molecules 9. A Ramachandran plot provides information about: (A) Protein backbone dihedral angles (φ and ψ) (B) DNA melting temperature (C) Radiation absorption (D) Ultrasound reflection patterns 10. In X-ray crystallography, the Bragg’s law is used to relate: (A) Force and acceleration (B) Wavelength, angle, and lattice spacing (C) Temperature and entropy (D) Energy and mass 11. The unit cell in crystallography represents: (A) The largest crystal structure (B) The smallest repeating structural unit in a crystal (C) A protein domain (D) A DNA nucleotide 12. Cryo-EM requires samples to be: (A) Crystallized (B) Frozen in vitreous ice (C) Embedded in paraffin (D) Dried in vacuum 13. Which technique provides high-resolution structural details of membrane proteins? (A) X-ray crystallography (B) Cryo-EM (C) NMR spectroscopy (D) All of the above 14. The double helix structure of DNA was discovered by: (A) Rosalind Franklin (B) Watson and Crick (C) Linus Pauling (D) Max Perutz 15. Hydrogen bonds in DNA occur between: (A) Phosphate groups (B) Nitrogenous bases (C) Sugar molecules (D) Backbone carbons 16. Major and minor grooves are structural features of: (A) RNA (B) DNA double helix (C) Protein helices (D) Polysaccharides 17. Small-angle X-ray scattering (SAXS) provides: (A) Atomic-level detail (B) Low-resolution shapes of macromolecules in solution (C) Nuclear resonance signals (D) Ultrasound wave patterns 18. The radius of gyration (Rg) from SAXS describes: (A) Crystal symmetry (B) Overall size and compactness of a molecule (C) MRI magnetic fields (D) Ultrasound frequency 19. Protein folding is driven primarily by: (A) Ionic interactions (B) Hydrophobic effect (C) Radiation scattering (D) Magnetic fields 20. The stability of protein tertiary structure is often due to: (A) Disulfide bridges and hydrophobic interactions (B) Ionizing radiation (C) Ultrasound vibrations (D) Crystallization defects 21. Chaperone proteins assist in: (A) Radiation shielding (B) Correct folding of proteins (C) X-ray crystallography (D) MRI imaging 22. Circular dichroism spectra in the far-UV region are used to analyze: (A) Nucleotide base stacking (B) Protein secondary structure (C) Lipid bilayers (D) Crystallographic unit cells 23. Fluorescence resonance energy transfer (FRET) provides information on: (A) Long-range interactions and distances between biomolecules (B) X-ray diffraction (C) MRI spectroscopy (D) Ultrasound signals 24. Which fluorophore is commonly used in structural biophysics? (A) GFP (Green Fluorescent Protein) (B) Hemoglobin (C) Uric acid (D) Insulin 25. A protein domain is defined as: (A) The crystal lattice unit (B) A distinct functional and structural unit of a protein (C) A DNA regulatory sequence (D) A lipid bilayer section 26. Structural motifs like helix-turn-helix are important in: (A) DNA-protein interactions (B) Ultrasound therapy (C) Radiation shielding (D) MRI analysis 27. The α-helix is stabilized by: (A) Hydrogen bonds between carbonyl oxygen and amide hydrogen (B) Ionic interactions between R-groups (C) Disulfide linkages (D) Hydrophobic collapse 28. Beta-barrel proteins are commonly found in: (A) Membranes as transport channels (B) DNA double helices (C) Cytoskeleton fibers (D) Nuclear pores only 29. NMR NOESY spectra provide: (A) X-ray diffraction patterns (B) Distance constraints between protons in biomolecules (C) Protein synthesis rates (D) Radiation dose levels 30. The hydrophobic core of proteins is generally composed of: (A) Polar amino acids (B) Nonpolar amino acids (C) Charged amino acids (D) Aromatic bases 31. Protein misfolding is associated with: (A) Diabetes only (B) Neurodegenerative diseases like Alzheimer’s (C) MRI imaging (D) DNA replication 32. Cryo-EM has revolutionized structural biology mainly because: (A) It avoids the need for crystallization (B) It uses only MRI fields (C) It replaces fluorescence completely (D) It uses radiation therapy 33. In crystallography, resolution of 2 Å means: (A) Atoms can be distinguished within ~0.2 nm (B) No atomic details visible (C) Only molecular shape seen (D) Protein folding not resolved 34. Structural information from NMR is limited by: (A) Size of biomolecule (works best for < 40 kDa) (B) Radiation damage (C) Magnetic field instability (D) Poor crystallization 35. Secondary structures are stabilized mainly by: (A) Hydrogen bonding (B) Covalent bonds (C) Hydrophobic effect only (D) Radiation energy 36. The collagen triple helix is stabilized by: (A) Glycine at every third residue (B) High hydrophobic content (C) Disulfide bridges (D) Beta-sheets 37. DNA denaturation can be monitored by: (A) Increase in UV absorbance at 260 nm (B) MRI imaging (C) Ultrasound scattering (D) Radiation therapy 38. The melting temperature (Tm) of DNA is the point where: (A) Half of the DNA is denatured (B) DNA is fully crystallized (C) All hydrogen bonds are removed (D) Only RNA is present 39. Fiber diffraction studies were used to study: (A) Collagen and DNA structures (B) Radiation therapy (C) Ultrasound imaging (D) MRI fields 40. Electron density maps in crystallography represent: (A) Probability distribution of electrons around atoms (B) Proton scattering (C) Radiation dose (D) Ultrasound beams 41. Structural homology modeling is used to: (A) Predict protein 3D structures based on known templates (B) Generate ultrasound beams (C) Simulate MRI gradients (D) Measure radiation doses 42. Synchrotron radiation is often used in: (A) High-resolution X-ray crystallography (B) Ultrasound scans (C) Radiation therapy only (D) MRI spectroscopy 43. Hydrogen-deuterium exchange (HDX) combined with mass spectrometry gives: (A) Information on protein dynamics and flexibility (B) MRI contrast (C) Radiation dose (D) Ultrasound resonance 44. Single-molecule FRET (smFRET) allows measurement of: (A) Conformational changes in individual biomolecules (B) Radiation doses in cells (C) Ultrasound reflection in tissues (D) MRI magnetic gradients 45. A structural motif is defined as: (A) A recurrent arrangement of secondary structures (B) A nuclear pore complex (C) A radiation pattern (D) A lipid bilayer 46. Which amino acid is often found in turns of proteins? (A) Glycine (B) Valine (C) Phenylalanine (D) Tryptophan 47. Triple helical nucleic acid structures are called: (A) Z-DNA (B) Triplex DNA (C) G-quadruplexes (D) B-DNA 48. G-quadruplex structures are formed by: (A) Guanine-rich DNA sequences (B) Cytosine pairing only (C) Protein aggregation (D) Radiation damage 49. Which structural method directly measures distances between spin labels? (A) EPR (Electron Paramagnetic Resonance) spectroscopy (B) MRI (C) PET (D) Ultrasound 50. Structural biophysics combines: (A) Physics, biology, and chemistry to study biomolecular structures (B) Radiation therapy and MRI (C) Ultrasound and PET (D) Astronomy and geology Molecular Biophysics – MCQsCellular Biophysics – MCQsMembrane Biophysics – MCQsNeurobiophysics – MCQsRadiation Biophysics – MCQsMedical Biophysics – MCQsComputational Biophysics – MCQsStructural Biophysics – MCQsBiophysical Chemistry – MCQsBioenergetics – MCQsBiomechanics – MCQsSystems Biophysics – MCQsBiomolecular Interactions – MCQsBiophysical Methods & Instrumentation – MCQsQuantum Biophysics – MCQsThermodynamics & Statistical Mechanics in Biology – MCQsBiophysics of Macromolecules – MCQs Electrophysiology – MCQsPhotobiophysics – MCQsNanobiophysics – MCQs