12 public questions tagged with this topic.
Competitive inhibitors compete with the substrate for the enzyme’s active site, reducing enzyme activity.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzyme Action and Factors Affecting Enzyme Activity
Enzymes are not consumed in reactions; they remain unchanged and can be reused.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzyme Action and Factors Affecting Enzyme Activity
Competitive inhibitors compete with the substrate by binding to the enzyme's active site. Non-competitive inhibitors bind elsewhere, and some inhibitors are reversible.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzyme Action and Factors Affecting Enzyme Activity
Both Zn²⁺ and Mg²⁺ act as cofactors for various enzymes, helping in their catalytic activity.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzymes - Properties Classification and Cofactors
Partial digestion arises when conditions prevent all sites from being cleaved. Impure DNA containing proteins, salts, or residual phenol inhibits enzyme binding. Incorrect buffer pH, Mg2+ concentration, or suboptimal temperature reduces catalytic activity. Too little enzyme or too short incubation also leaves some sites uncut. Excess enzyme drives reaction toward completion and, beyond optimum, may cause star activity with nonspecific cutting, not partial patterns. Therefore excess enzyme does not cause incomplete cleavage but rather overdigestion, making it non-contributory to partial digestion.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
90% of cancers, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
The rate at which an enzyme converts 1 mole of substrate per second is the scientifically accurate answer to this question. Within the study of Enzyme Kinetics, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of The rate at which an enzyme converts 1 mole of substrate per second directly address what is being asked. Among the other options, The total enzyme concentration, The molecular weight of the enzyme, and The concentration of cofactors do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 6
μmol of substrate converted per minute accurately defines or describes the concept asked in this question. Within Km and Vmax calculation, precise definitions and terminology are essential for clear scientific communication. The other options (The time required for an enzyme to reach Vmax, The molecular weight of the enzyme, and The total amount of enzyme present) 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
Kcat = Vmax / [E] 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 Km and Vmax calculation, Kcat = Vmax / [E] plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Kcat = Km / Vmax, Kcat = [S] / Vmax, and Kcat = Vmax × Km) 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 enzyme concentration 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 Km and Vmax calculation, The enzyme concentration plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (The substrate concentration, The enzyme-substrate affinity, and The reaction temperature only) 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
Forms a strong covalent bond with the 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, Forms a strong covalent bond with the enzyme plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Forms a weak hydrogen bond with the enzyme, Can be removed by dialysis, and Can be reversed by increasing substrate concentration) 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
Answer: C) Photolyase activity. For cryptochrome, remember the key idea and you’ll land on this option; the distractors usually swap cause and effect or confuse similar terms. Avoid: A) DNA-binding ability; B) Chromophore; D) Nuclear localization. Name the process first, then pick the option that describes it — don’t reverse cause and effect.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.
