Membrane Biophysics – MCQs 50 Score: 0 Attempted: 0/50 Subscribe 1. The plasma membrane is primarily described by the: (A) Central dogma model (B) Fluid mosaic model (C) Lock-and-key model (D) Proton pump model 2. The main structural component of biological membranes is: (A) Proteins (B) Lipids (C) Carbohydrates (D) Nucleic acids 3. The amphipathic nature of membrane lipids means they have: (A) Only hydrophobic parts (B) Only hydrophilic parts (C) Both hydrophobic and hydrophilic regions (D) Neither polar nor nonpolar groups 4. The most common lipid in eukaryotic plasma membranes is: (A) Cholesterol (B) Phosphatidylcholine (C) Sphingomyelin (D) Triglyceride 5. Cholesterol in membranes primarily functions to: (A) Store energy (B) Stabilize membrane fluidity (C) Bind to DNA (D) Drive protein folding 6. Integral membrane proteins differ from peripheral proteins by: (A) Being loosely attached (B) Being embedded in the lipid bilayer (C) Not interacting with lipids (D) Being soluble in water only 7. Which type of transport requires ATP? (A) Passive diffusion (B) Facilitated diffusion (C) Active transport (D) Osmosis 8. The sodium-potassium ATPase is an example of: (A) Uniport (B) Symport (C) Antiport (D) Facilitated diffusion 9. Which technique is most widely used to study membrane fluidity? (A) Patch-clamp (B) Fluorescence recovery after photobleaching (FRAP) (C) Gel electrophoresis (D) Atomic absorption spectroscopy 10. Lipid rafts are microdomains enriched in: (A) Cholesterol and sphingolipids (B) Proteins only (C) Phosphatidylcholine only (D) Nucleic acids 11. The thickness of a typical lipid bilayer is approximately: (A) 2–3 nm (B) 4–5 nm (C) 8–10 nm (D) 20 nm 12. Passive transport moves molecules: (A) Against concentration gradient (B) With concentration gradient (C) Using ATP (D) By vesicle trafficking 13. Aquaporins facilitate transport of: (A) Sodium ions (B) Potassium ions (C) Water molecules (D) Glucose 14. The driving force for osmosis across membranes is: (A) Protein concentration (B) Water potential difference (C) DNA structure (D) ATP hydrolysis 15. Gated ion channels open in response to: (A) ATP hydrolysis only (B) Specific stimuli like voltage or ligands (C) Osmotic pressure (D) Protein denaturation 16. Which ion channel is essential for action potential propagation in neurons? (A) Calcium channel (B) Potassium channel (C) Sodium channel (D) Chloride channel 17. The patch-clamp technique is used to measure: (A) Protein folding rates (B) Ion channel currents (C) Lipid bilayer thickness (D) ATP hydrolysis 18. The asymmetric distribution of lipids in bilayers is maintained by: (A) Flipases and floppases (B) ATP synthase (C) Exocytosis (D) Gap junctions 19. The main factor influencing membrane permeability to ions is: (A) Membrane proteins (B) DNA content (C) Lipid rafts (D) Carbohydrate concentration 20. Endocytosis is an example of: (A) Passive diffusion (B) Active membrane transport (C) Osmosis (D) Ion channel transport 21. Lipid bilayers spontaneously form because of: (A) DNA replication (B) Hydrophobic effect (C) Hydrogen bonds only (D) Peptide bond formation 22. The electrical potential across a cell membrane is typically: (A) +70 mV (B) –70 mV (C) 0 mV (D) –200 mV 23. The protein channels that allow selective ion passage are called: (A) Enzymes (B) Ion channels (C) Receptors (D) Ribosomes 24. Which factor decreases membrane fluidity? (A) High temperature (B) Unsaturated fatty acids (C) Cholesterol at low temperatures (D) Saturated fatty acids 25. Membrane potential arises due to: (A) Equal distribution of ions (B) Unequal ion distribution across the membrane (C) DNA packaging (D) Ribosome activity 26. Which is a type of secondary active transport? (A) Facilitated diffusion (B) Symport and antiport mechanisms (C) Osmosis (D) FRAP 27. Detergents solubilize membranes by: (A) Forming micelles with membrane lipids (B) Breaking peptide bonds (C) Hydrolyzing nucleotides (D) Polymerizing proteins 28. The electrochemical gradient combines: (A) Chemical concentration gradient and membrane potential (B) ATP and DNA gradients (C) Protein folding energy and temperature (D) Lipid and carbohydrate interactions 29. Vesicle fusion with membranes is mediated by: (A) SNARE proteins (B) Tubulin (C) Actin filaments (D) Histones 30. Which type of transport moves glucose into red blood cells? (A) Facilitated diffusion via GLUT transporters (B) Osmosis (C) Simple diffusion (D) Active transport with ATP 31. The role of spectrin in membranes is to: (A) Pump ions (B) Provide structural support to the cytoskeleton (C) Transport water (D) Bind DNA 32. The primary determinant of membrane thickness is: (A) Protein content (B) Length of fatty acid tails (C) Cholesterol content only (D) DNA length 33. Which molecule can freely diffuse across the lipid bilayer? (A) Glucose (B) Sodium ions (C) Oxygen (D) Proteins 34. Which method can create artificial planar lipid bilayers for studies? (A) Black lipid membrane technique (B) SDS-PAGE (C) Western blotting (D) PCR 35. Caveolae are specialized membrane invaginations rich in: (A) Caveolin proteins (B) DNA and histones (C) ATP synthase (D) Actin filaments 36. Which transport process is used by CFTR protein? (A) Glucose symport (B) Chloride ion channel transport (C) Proton pump (D) Calcium antiport 37. The Goldman-Hodgkin-Katz equation calculates: (A) Protein folding rate (B) Membrane potential considering multiple ions (C) DNA melting point (D) Lipid bilayer thickness 38. Peripheral proteins attach to membranes via: (A) Hydrophobic interactions and ionic bonds (B) Insertion into bilayer (C) Transmembrane helices (D) Peptide bonds 39. Which molecule increases membrane rigidity at high temperatures? (A) Cholesterol (B) Glycogen (C) DNA (D) ATP 40. Gap junctions are formed by proteins called: (A) Connexins (B) Integrins (C) Tubulins (D) Myosins 41. Proton pumps in membranes are essential for: (A) Generating proton gradients (B) Forming peptide bonds (C) Folding proteins (D) Binding DNA 42. The driving force for potassium efflux from a cell is: (A) Protein synthesis (B) Electrochemical gradient (C) DNA replication (D) Lysosome activity 43. Liposomes are artificially prepared: (A) Protein aggregates (B) DNA vesicles (C) Lipid bilayer vesicles (D) Carbohydrate polymers 44. Voltage-gated channels open in response to: (A) Ion concentration only (B) Changes in membrane potential (C) Protein phosphorylation (D) ATP hydrolysis 45. The Nernst equation is used to calculate: (A) Equilibrium potential for a single ion (B) Gibbs free energy (C) Protein folding entropy (D) DNA melting temperature 46. Which factor increases membrane fluidity? (A) High cholesterol content at low temperatures (B) Saturated fatty acids (C) Longer fatty acid chains (D) Unsaturated fatty acids 47. The main barrier to ion movement across membranes is: (A) Hydrophobic lipid core (B) Protein crowding (C) ATP hydrolysis (D) Carbohydrate layer 48. Receptor-mediated endocytosis involves: (A) Clathrin-coated vesicles (B) Random diffusion (C) SNARE proteins only (D) Exocytosis 49. Which organelle is enclosed by a double membrane with transport proteins? (A) Nucleus (B) Lysosome (C) Golgi apparatus (D) Ribosome 50. The lateral mobility of lipids in membranes is best described as: (A) Free rotation only (B) Two-dimensional diffusion within the bilayer (C) No movement (D) Vertical flipping without enzymes 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