14 public questions tagged with this topic.
Not all restriction enzymes produce sticky ends; some generate blunt ends when cutting DNA.
Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Tools - Restriction Enzymes - Molecular Scissors
Enzymes function by lowering the activation energy required for a chemical reaction to occur, thus speeding up the reaction.
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
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
PylB methylornithine synthase is radical S-adenosylmethionine family enzyme initiating pyrrolysine synthesis by transforming L-lysine into (3R)-3-methyl-D-ornithine. Reaction involves reductive cleavage of SAM generating 5'-deoxyadenosyl radical that abstracts hydrogen from lysine, followed by carbon skeleton rearrangement, amino group migration, epimerization. PylB harbors oxygen-sensitive [4Fe-4S] cluster essential for radical generation and conserved CxxxCxxC motif coordinating cluster. This methylornithine synthase activity expands known radical SAM superfamily functions in amino acid mutase reactions, resembling lysine 2,3-aminomutase chemistry adapted to generate branched ornithine intermediate critical for pyrroline formation providing insight into evolution of cofactor-independent radical catalysis.
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 3: PylB Methylornithine Synthase Radical SAM Mechanism
cAMP binding strengthens R–C interaction, 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)
a molecular memory enzyme, 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)
Converting pyruvate into acetyl-CoA accurately defines or describes the concept asked in this question. Within Enzymes Basics, precise definitions and terminology are essential for clear scientific communication. The other options (Hydrolyzing ATP, Facilitating electron transport, and Synthesizing glucose) 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
The location where the substrate binds and undergoes reaction 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 Enzymes Basics, The location where the substrate binds and undergoes reaction plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (A rigid structure that never changes, A site that always binds only one specific substrate, and Composed only of non-polar amino acids) 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 loses its catalytic function correctly describes the effect or change asked about in this question. In Enzyme Kinetics, understanding cause-and-effect relationships is essential for predicting biological outcomes. It loses its catalytic function occurs because of specific molecular interactions, thermodynamic principles, or regulatory mechanisms that govern this biological process. The other options (It increases its catalytic efficiency, It forms an enzyme-substrate complex more efficiently, and It increases Km) describe either opposite effects, effects that occur under different conditions, or changes associated with unrelated processes.
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
Phospholipase 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 Lipids without annotations, Phospholipase plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Lipase, Amylase, and Ligase) 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. 10
