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.
Read DetailsBCH4024 OC Sp26 E1 Q4: A researcher attempts to change the shape and stability of a mammalian cell by testing the effect of several different inhibitors on the cytoskeletal proteins. Which cytoskeletal structure is affected by an inhibitor that affects the polymerization of α-keratin?
Read DetailsBCH4024 OC Sp26 E1 Q26: Hemoglobin in arterial blood is approximately 96% saturated with oxygen, while peripheral blood saturation drops to about 64%. This difference is critical for oxygen delivery. Which feature of hemoglobin makes this difference in oxygen percentage effective for mammalian respiration or breathing?
Read DetailsBCH4024 OC Sp26 E1 Q11: A protein is isolated from a thermophilic organism and shows an unusually high proportion of leucine, isoleucine, and valine residues. Structural analysis reveals that these residues are predominantly buried in the protein core. This distribution contributes directly to the protein’s stability at elevated temperatures. Which interaction most directly explains this stabilization?
Read DetailsBCH4024 OC Sp26 E1 Q23: A company scientist is purifying an enzyme with a pI of 8.5 from a crude extract at pH 7.0 using ion-exchange chromatography. During loading, the target protein binds strongly while many contaminants flow through. Which principle best explains this behavior?
Read DetailsBCH4024 OC Sp26 E1 Q20: In the Anfinsen experiment, he denatures Ribonuclease A using urea and β-mercaptoethanol, rendering it inactive. After removing both reagents, Ribonuclease A regains its native conformation and full catalytic activity. Which conclusion most directly supports this observation?
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