Đề 2 – Bài tập, đề thi trắc nghiệm online Hóa sinh enzyme

A A. It increases the equilibrium constant. B B. It decreases the equilibrium constant. C C. It does not affect the equilibrium constant. D D. It reverses the equilibrium constant.

A A. To permanently bind to the active site and block substrate binding. B B. To provide the enzyme's tertiary structure. C C. To assist in the catalytic reaction, often by carrying electrons or functional groups. D D. To denature the enzyme at high temperatures.

A A. Km B B. Vmax C C. 1/Km D D. 1/Vmax

A A. Increasing the temperature of the system. B B. Providing energy to the reaction. C C. Lowering the Gibbs free energy change of the reaction. D D. Lowering the activation energy of the reaction.

A A. Remove water to form new bonds. B B. Add water to break chemical bonds. C C. Rearrange molecules without changing their elemental composition. D D. Transfer electrons between molecules.

A A. DNA polymerase B B. Amylase C C. Hemoglobin D D. Insulin

A A. The maximum reaction rate. B B. The substrate concentration at which the reaction rate is half of Vmax. C C. The enzyme concentration at which the reaction rate is maximum. D D. The dissociation constant of the enzyme-substrate complex.

A A. Binding to the enzyme at a site other than the active site. B B. Binding irreversibly to the active site. C C. Binding to the active site and preventing substrate binding. D D. Changing the shape of the active site after substrate binding.

A A. Highly acidic (pH 1-3) B B. Slightly acidic (pH 4-6) C C. Neutral (pH 7) D D. Slightly alkaline (pH 8-10)

A A. Hydrolysis reactions B B. Isomerization reactions C C. Oxidation-reduction reactions D D. Ligation reactions

A A. Non-competitive inhibition. B B. Uncompetitive inhibition. C C. Competitive inhibition. D D. Mixed inhibition.

A A. The enzyme's active site is a rigid shape that perfectly matches the substrate. B B. The substrate changes shape to fit into the enzyme's active site. C C. The enzyme's active site changes shape slightly upon substrate binding to achieve optimal fit. D D. Enzyme and substrate shapes are irrelevant for catalysis.

A A. Covalent modification of the enzyme's active site. B B. Binding of a molecule at a site other than the active site, affecting enzyme conformation and activity. C C. Direct competition with the substrate for binding to the active site. D D. Irreversible denaturation of the enzyme.

A A. Increasing the activation energy of the reaction. B B. Decreasing the activation energy of the reaction. C C. Increasing the temperature of the reaction. D D. Decreasing the temperature of the reaction.

A A. The overall size of the enzyme molecule. B B. The amino acid sequence of the enzyme. C C. The shape of the enzyme's active site. D D. The presence of cofactors.

A A. Km (Michaelis constant) B B. Vmax (maximum velocity) C C. Both Km and Vmax D D. Neither Km nor Vmax

A A. A stable intermediate in the reaction pathway. B B. The final product of the reaction. C C. A high-energy, unstable intermediate where bonds are being broken and formed. D D. The enzyme-substrate complex before catalysis.

A A. The substrate of the enzyme inhibits its own production. B B. The end product of a pathway inhibits an enzyme early in the pathway. C C. An activator molecule increases the activity of the first enzyme in the pathway. D D. Enzymes are activated by the accumulation of their products.

A A. Enzymes only increase the rate of the forward reaction. B B. Enzymes only increase the rate of the reverse reaction. C C. Enzymes increase the rate of both forward and reverse reactions equally. D D. Enzymes decrease the rate of both forward and reverse reactions equally.

A A. Breaking down molecules by adding water. B B. Transferring functional groups between molecules. C C. Joining two molecules together, often requiring ATP hydrolysis. D D. Removing groups to form double bonds.

A A. The free enzyme only. B B. The enzyme-substrate complex only. C C. Either the free enzyme or the enzyme-substrate complex. D D. A site unrelated to the enzyme.

A A. Hydrolases B B. Lyases C C. Isomerases D D. Polymers

A A. Phosphorylation of the enzyme to activate it. B B. Binding of an allosteric activator. C C. Cleavage of a peptide bond to convert an inactive precursor into an active enzyme. D D. Removal of a phosphate group to activate the enzyme.

A A. Enzymes are classified into four major classes based on their substrate specificity. B B. Enzymes are classified into six major classes based on the type of reaction they catalyze. C C. Enzyme classification is based on their cellular location. D D. Enzyme classification is determined by their molecular weight.

A A. To catalyze oxidation-reduction reactions. B B. To catalyze the rearrangement of atoms within a molecule. C C. To catalyze the joining of two molecules. D D. To catalyze the breakdown of large molecules into smaller ones using water.

A A. Enzyme activity decreases linearly with increasing temperature. B B. Enzyme activity increases linearly with increasing temperature. C C. Enzyme activity increases with temperature up to an optimum, then decreases sharply. D D. Temperature has no significant effect on enzyme activity.

A A. The cleavage of bonds using water. B B. The transfer of functional groups from one molecule to another. C C. The formation of double bonds. D D. The rearrangement of atoms within a molecule.

A A. Enzyme concentration B B. Substrate concentration C C. Presence of inhibitors or activators D D. The color of the reaction mixture

A A. Oxidation-reduction reactions. B B. Transfer of functional groups. C C. Hydrolysis reactions. D D. Cleavage of bonds by means other than hydrolysis or oxidation, often forming double bonds.

A A. The reaction rate decreases linearly. B B. The reaction rate increases linearly without limit. C C. The reaction rate increases to a maximum value (Vmax) and then plateaus. D D. The reaction rate remains constant regardless of substrate concentration.