Đề 1 – Bài tập, đề thi trắc nghiệm online Hóa sinh enzyme

A A. pH only affects the rate of substrate diffusion to the enzyme. B B. pH changes can alter the ionization state of amino acid residues in the active site, affecting substrate binding and catalysis. C C. Enzymes are equally active across all pH ranges. D D. pH only affects the overall concentration of the enzyme in solution.

A A. The substrate of the enzyme. B B. An intermediate product of the pathway. C C. The final product of the metabolic pathway. D D. A reactant from a completely different metabolic pathway.

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

A A. Hydrolysis of peptide bonds. B B. Transfer of amino groups. C C. Oxidation of alcohols to aldehydes. D D. Racemization of chiral centers.

A A. Formation of new bonds. B B. Isomerization reactions. C C. Removal of groups to form double bonds or rings. D D. Transfer of phosphate groups.

A A. Hydrolases B B. Isomerases C C. Ligases D D. Oxidoreductases

A A. Hydrolysis B B. Oxidation C C. Phosphorylation D D. Reduction

A A. Cofactors are always proteins that bind to the enzyme to activate it. B B. Cofactors can be either inorganic ions or organic molecules that assist enzyme function. C C. Cofactors are substrates that are converted into products by the enzyme. D D. Cofactors are always consumed during the enzymatic reaction.

A A. The substrate concentration required to reach half-maximal velocity. B B. The reaction rate at very low substrate concentrations. C C. The maximum rate of reaction when the enzyme is saturated with substrate. D D. The dissociation constant of the enzyme-substrate complex.

A A. To break down large molecules into smaller ones. B B. To synthesize complex molecules from simpler ones. C C. To rearrange atoms within a molecule to form isomers. D D. To transfer electrons between molecules.

A A. To determine the amino acid sequence of an enzyme. B B. To measure the rate of an enzyme-catalyzed reaction. C C. To purify enzymes from cell extracts. D D. To determine the three-dimensional structure of an enzyme.

A A. They increase Km but do not change Vmax. B B. They decrease Vmax but do not change Km. C C. They increase both Km and Vmax. D D. They decrease both Km and Vmax.

A A. DNA polymerase B B. Ribonucleotide reductase C C. Transpeptidase D D. Reverse transcriptase

A A. By increasing the activation energy of the reaction. B B. By decreasing the activation energy of the reaction. C C. By increasing the temperature of the reaction. D D. By decreasing the temperature of the reaction.

A A. Increases Km and Vmax. B B. Decreases Km and Vmax. C C. Increases Km and decreases Vmax. D D. Decreases Km and increases Vmax.

A A. Ion exchange chromatography B B. Affinity chromatography C C. Size exclusion chromatography D D. Isoelectric focusing

A A. Oxidoreductase B B. Transferase C C. Hydrolase D D. Lyase

A A. To increase the overall rate of a single reaction in all tissues. B B. To allow for tissue-specific regulation of enzyme activity. C C. To simplify the genetic coding required for enzyme production. D D. To reduce the specificity of enzymes for their substrates.

A A. The concentration of the enzyme in the cell. B B. The temperature at which the reaction occurs. C C. The unique three-dimensional structure of the enzyme's active site. D D. The presence of inhibitors in the reaction mixture.

A A. By binding non-covalently to the active site. B B. By binding reversibly to an allosteric site. C C. By forming covalent bonds with amino acid residues in the active site. D D. By changing the pH of the enzyme's environment.

A A. Amylase B B. Cellulase C C. Papain D D. Lipase

A A. Substrate binding directly to the active site. B B. Regulation by molecules binding at a site other than the active site. C C. Regulation only by irreversible inhibitors. D D. Regulation solely through changes in temperature.

A A. Joining two molecules together. B B. Rearranging atoms within a molecule. C C. Breaking bonds by the addition of water. D D. Transferring functional groups between molecules.

A A. HMG-CoA reductase B B. Cholesterol esterase C C. Lipoprotein lipase D D. Acyl-CoA cholesterol acyltransferase (ACAT)

A A. To increase the diffusion rate of substrates between active sites. B B. To decrease the efficiency of product formation. C C. To enhance reaction rate and prevent accumulation of intermediates. D D. To reduce the overall amount of enzyme protein needed in the cell.

A A. To provide structural support to the enzyme. B B. To bind cofactors necessary for enzyme activity. C C. To provide a specific environment for substrate binding and catalysis. D D. To regulate the overall rate of enzyme production in the cell.

A A. Vmax only. B B. Km only. C C. Both Vmax and Km. D D. Neither Vmax nor Km.

A A. Peptide bonds only. B B. Glycosidic bonds only. C C. Carbon-carbon, carbon-oxygen, carbon-nitrogen, and carbon-sulfur bonds. D D. Hydrogen bonds only.

A A. Amylases B B. Lipases C C. Proteases D D. Cellulases

A A. The maximum reaction rate when the enzyme is saturated with substrate. B B. The substrate concentration at which the reaction rate is half of Vmax. C C. The rate constant for the breakdown of the enzyme-substrate complex. D D. The equilibrium constant for substrate binding to the enzyme.