BS 161 MSU Exam 2 Questions with Complete Solutions (Latest 2025) Identify the molecules that comprise a lipid - Correct Answers ✅Carbon, Hydrogen, Oxygen, Glycerol Explain the molecular difference between saturated and unsaturated fats - Correct Answers ✅Saturated fats are solid, have the maximum number of Hydrogen molecules, and no double bonds where as Unsaturated fats are liquid at room temp, have less than the max number of Hydrogen molecules, and contain double bonds Explain why, based on their properties, phospholipids spontaneously form a lipid bilayer - Correct Answers ✅Because of their polar hydrophilic heads (which go towards
outside) and non-polar hydrophobic tails(more interior): they
are amphipathic Predict how changes in lipid structure related to the degree of saturation and polarity will impact their behavior in biological systems - Correct Answers ✅Increasing amount of double bonds (degree of unsaturation) increases the fluidity of the membrane because more double bonds means more unsaturated and ability to flow Increasing the amount of fatty acid saturation decreases the fluidity of the membrane Increasing the temperature increases the likelihood for the membrane to flow 1 / 3
BS 161 MSU Exam 2 Questions with Complete Solutions (Latest 2025) Describe the fluid mosaic model of a membrane structure - Correct Answers ✅a membrane is a fluid structure with a "mosaic" of various proteins embedded in it Explain how membrane fluidity is influenced by temperature and membrane composition - Correct Answers ✅The higher the temp the more fluid Explain how cholesterol resists changes in membrane fluidity as temps change - Correct Answers ✅As the temperatures rise cholesterol restrains movement, as it lowers it maintains fluidity At moderate temps it reduces fluidity by reducing movement at low temps it hinders solidification by disrupting regular packing of phospholipids Integral vs Peripheral Proteins - Correct Answers ✅Integral proteins penetrate the hydrophobic core where as Peripheral bind to the surface of the membrane The six roles of membrane proteins - Correct Answers ✅transporter, enzyme, cell-surface receptor, identity marker, cell-to-cell adhesion, cytoskeleton anchor Explain the role of membrane carbohydrates in cell-cell recognition - Correct Answers ✅The ability of a cell to distinguish other cells based on recognition of membrane 2 / 3
BS 161 MSU Exam 2 Questions with Complete Solutions (Latest 2025) carbohydrates. The glycolipids and glycoproteins attached to the outside of plasma membranes varies.Explain how the polarity of a molecule affects how it moved across a membrane - Correct Answers ✅Non polar, hydrophobic molecules pass through more easily and vise versa bc they are being pulled by non-polar tails easiest 1.hydrophobic molecules
- small, uncharged polar molecules
- / 3
3.large uncharged polar molecules hardest 4. ions (charged molecules) Distinguish between channel proteins and carrier proteins - Correct Answers ✅channel proteins only transport substances through membranes passively, career proteins can transport ions and molecules either passively through diffusion or actively Explain how aquaporins facilitate the passage of water through membranes - Correct Answers ✅Aquaporins allow the transfer of water across a membrane 10x faster bc they have polar regions of functional groups that interact with water Define diffusion - Correct Answers ✅the tendency for molecules to spread out evenly into the available space