BCH4024 OC Sp26 E1 Q22: Levinthal’s paradox highlights a fundamental issue in protein folding kinetics. If a protein sampled all possible conformations randomly, folding would take longer than the age of the universe. Yet proteins fold on biologically relevant timescales. Which concept best resolves this paradox?

BCH4024 OC Sp26 E1 Q27: A muscle cell experiences a sudden drop in intracellular oxygen concentration during intense exercise. Myoglobin responds by releasing bound O₂ to support mitochondrial respiration. This behavior is best explained by myoglobin’s oxygen-binding characteristics. Which property most directly enables this response?

BCH4024 OC Sp26 E1 Q40: What type of inhibition is represented by the following Lineweaver–Burk plot?

BCH4024 OC Sp26 E1 Q31: A metal-dependent enzyme loses activity when Mg²⁺ is removed from the reaction mixture. Structural analysis shows accumulation of a negative charge in the transition state during catalysis. Which role of Mg²⁺ best explains the loss of activity?

BCH4024 OC Sp26 E1 Q12: A peptide bond typically adopts a trans configuration because it minimizes steric hindrance between adjacent side chains. However, one amino acid increases the likelihood of a cis peptide bond. Which amino acid most commonly stabilizes a cis peptide bond?

BCH4024 OC Sp26 E1 Q2: A researcher observes that a reaction with a positive enthalpy change still proceeds spontaneously inside a cell. Measurement show a large increase in the disorder of the surroundings. Which condition best explains this observation, based on the equation of Gibbs Free energy?

BCH4024 OC Sp26 E1 Q32: An enzyme exhibits strong stereospecificity, catalyzing reactions only for the L-enantiomer of a substrate. The D-enantiomer binds weakly and is not converted to product. What is the MOST accurate explanation?

BCH4024 OC Sp26 E1 Q3: There is a structural hierarchy in the molecular organization of cells. (i) Monomeric units interact to build macromolecules, and (ii) macromolecules interact to build supramolecular complexes. What bonds are important for the interactions labelled (i) and (ii)?

BCH4024 OC Sp26 E1 Q48: A researcher observes that a lipid triacylglyceride sample remains solid and tightly packed at room temperature despite having the same chain length as another lipid sample that is a liquid. Which structural feature best explains this difference in physical state between the two samples?

BCH4024 OC Sp26 E1 Q10: Lysine has pKa values of 2.2 (α-COOH), 9.0 (α-NH₃⁺), and 10.5 (ε-NH₃⁺). The pH of the solution is adjusted to 11.5. Based on the relative protonation states, determine the net charge of lysine at this pH. Choose the closest value.