7 public questions tagged with this topic.
Not all enzyme inhibitors permanently deactivate enzymes; some are reversible.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzyme Action and Factors Affecting Enzyme Activity
Diisopropyl phosphofluoridate (DIPF) is the accurate response regarding enzymatic activity or regulation described in this question. Enzymes are biological catalysts that accelerate reactions by lowering activation energy through specific substrate binding and transition state stabilization. In the context of Enzyme Inhibition, Diisopropyl phosphofluoridate (DIPF) plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Sulfonamide, Methotrexate, and Malonate) are either different enzymes with distinct substrate specificities, act through different mechanisms, or are involved in separate metabolic pathways.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
It can either increase or decrease Km accurately defines or describes the concept asked in this question. Within Enzyme Inhibition, precise definitions and terminology are essential for clear scientific communication. The other options (It always increases Km, It has no effect on Km, and It only binds to the active site) either describe related but distinct concepts, use incorrect terminology, or confuse similar-sounding terms that have different scientific meanings. A thorough understanding of exact definitions helps distinguish between closely related biological concepts and is crucial for competitive examinations.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
Physostigmine is the correct choice because it does not accurately describe or belong to the category addressed in this question. In the context of Enzyme Inhibition, the other options (Methotrexate, Sulfonamide, and Malonate) are all valid and well-established concepts. Physostigmine is either unrelated to the topic, describes a different biological process, or represents a common misconception. Questions framed as 'which is NOT' require students to identify the exception among otherwise correct statements, demanding comprehensive knowledge of the topic rather than recognition of a single fact.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
Decrease in both Km and Vmax is the accurate response regarding enzymatic activity or regulation described in this question. Enzymes are biological catalysts that accelerate reactions by lowering activation energy through specific substrate binding and transition state stabilization. In the context of Enzyme Inhibition, Decrease in both Km and Vmax plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (No effect on Km but reduction in Vmax, Increase in both Km and Vmax, and Decrease in Km but constant Vmax) are either different enzymes with distinct substrate specificities, act through different mechanisms, or are involved in separate metabolic pathways.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
Inhibitor binds to both free enzyme and enzyme-substrate complex is the accurate response regarding enzymatic activity or regulation described in this question. Enzymes are biological catalysts that accelerate reactions by lowering activation energy through specific substrate binding and transition state stabilization. In the context of Enzyme Inhibition, Inhibitor binds to both free enzyme and enzyme-substrate complex plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Inhibitor binds only to the enzyme-substrate complex, Inhibitor and substrate compete for the same binding site, and Inhibitor binding increases enzyme activity) are either different enzymes with distinct substrate specificities, act through different mechanisms, or are involved in separate metabolic pathways.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
The active site of an enzyme is the accurate response regarding enzymatic activity or regulation described in this question. Enzymes are biological catalysts that accelerate reactions by lowering activation energy through specific substrate binding and transition state stabilization. In the context of Enzyme Inhibition, The active site of an enzyme plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (The enzyme-substrate complex, The allosteric site of an enzyme, and Both the active and allosteric sites) are either different enzymes with distinct substrate specificities, act through different mechanisms, or are involved in separate metabolic pathways.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
