🧬 Biochemistry Solved MCQs with Answers

Practice 1490 approved 🧬 Biochemistry questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

1490 solved MCQs

Which of the following is the most correct?Answer: Charged amino acids are seldom buried in the interior of a protein Which of the following forces is the most unfavorable for protein folding?Answer: Conformational entropy Since ΔG° = -RTlnKAnswer: A 10-fold increase in K decreases ΔG° by about 2.3*RT The correlation between free energy ΔG transfer between the aqueous/organic phases and the surface area of amino acid residuesAnswer: Reflects the reduction in solvent-accessible area during protein folding If the egg white protein, ovalbumin, is denatured in a hard-boiled egg, then which of the following is least affected?Answer: The primary structure of ovalbumin Buried hydrophobic side chains in a globular protein fit into a hole formed by the side chains ofAnswer: 5-7 other amino acids During successful purification scheme, this may be expected that theAnswer: Both (a) and (c) In ion-exchange chromatographyAnswer: Proteins are separated on the basis of their net charge Which of the following may be added to stabilize the protein after yeast cells disruption?Answer: All of these Gel-filtration chromatography separates on the basis ofAnswer: Size and shape using porous beads packed in a column Affinity chromatography deals with theAnswer: Specific binding of a protein constituents for another molecule A purified protein sample contains 10 μg of protein and has an enzyme activity of 1 m mole of ATP synthesized/sec (1 unit). What is the specific activity of the final purified sample?Answer: 100,000 units/mg Proteins separation can be carried out on the basis ofAnswer: All of these The best way to determine the location of protein in the purification scheme is to measure theAnswer: Rate of ATP synthesis In an SDS-PAGEAnswer: All of these Proteins can be visualized directly in gels byAnswer: Staining them with the dye In SDS-PAGE, the protein sample is firstAnswer: Treated with a reducing agent and then with anionic detergent followed by fractionation by electrophoresis Electrophoresis of histones and myoglobin under non-denaturing conditions (pH = 7.0) results inAnswer: Histones migrate to the cathode and myoglobin migrates to the anode In isoelectric focusing, proteins are separated on the basis of theirAnswer: Relative content of positively and negatively charged residue In a gel filtration columnAnswer: Both (a) and (b) In a native PAGE, proteins are separated on the basis ofAnswer: Net charge and size The subunit molecular weight as well as the number of subunits in the quaternary structure can be determined byAnswer: Combining information from (a)and (b) Proteins are separated in an SDS-PAGE experiment on the basis of theirAnswer: Molecular weight Which of the following organic groups are found in naturally occuring amino acids?Answer: All of these Polyprotic acids such as H₃PO₄, can act as acid-base buffersAnswer: at pH values around any of their pKₐ's The pH of a solution is determined byAnswer: Relative concentration of acids and bases The reactions of moleculesAnswer: Are the reactions of the functional groups Which of the following indicates that the pK of an acid is numerically equal to the pH of the solution when the molar concentration of the acid and its conjugate base are equal?Answer: Henderson-Hasselbalch equation Molecules in which the atoms are held together by __________ bonds have the strongest chemical linkages.Answer: Covalent Salt dissolves well in water as water moleculesAnswer: Surround the ions because of their charge but do not form hydrogen bonds