Enzyme Function P. Gyrase 1. Removes a damaged base by cleaving the bond between sugar and base Q. Deadenylase 2. Provides a swivel allowing one DNA strand to rotate around the other R. Glycosylase 3. Catalyses bond formation between 3'-OH and 5'-phosphate end of nucleotides in duplex DNA S. DNA ligase 4. Is an exoribonuclease that removes the poly(A) tail
Enzyme Function Matching
This question requires matching specific enzymes with their biological functions. Let's analyze each enzyme-function pair:
- P. Gyrase: DNA gyrase (a type II topoisomerase) introduces negative supercoiling into DNA and manages DNA topology during replication and transcription. Its function involves allowing strands to rotate relative to each other to relieve torsional stress. This matches function 2.
- Q. Deadenylase: This enzyme is crucial in regulating mRNA stability. It specifically removes the adenine residues (adenylation) from the 3' poly(A) tail of mRNA, acting as an exoribonuclease. This matches function 4.
- R. Glycosylase: DNA glycosylases are key enzymes in base excision repair (BER). They initiate the repair process by recognizing and removing damaged or modified bases from DNA, cleaving the glycosidic bond between the base and the deoxyribose sugar. This matches function 1.
- S. DNA ligase: DNA ligase is essential for DNA replication and repair. It joins DNA fragments (Okazaki fragments) by forming a phosphodiester bond between the 3'-hydroxyl end of one nucleotide and the 5'-phosphate end of an adjacent nucleotide. This matches function 3.
Matching Summary
Based on the analysis:
- P matches with 2
- Q matches with 4
- R matches with 1
- S matches with 3
Therefore, the correct matching is P-2; Q-4; R-1; S-3.
Important Questions from Enzyme Classification Catalytic and Regulatory Strategies
- Correctly match the Coenzyme with its respective involvement in a specific Reaction type.
Coenzyme Reaction type P. Thiamine pyrophosphate 1. Acyl group transfer Q. Tetrahydrofolate 2. Transfer of one carbon group R. Flavin adenine dinucleotide 3. Transfer of methyl group S. 5'-Deoxyadenosyl cobalamin 4. Oxidation-reduction 5. Aldehyde transfer - An enzyme catalyzes a reaction by
- The activity of an enzyme is expressed in International Units (IU). However, the S.I. unit for enzyme activity is Katal. One Katal is
- Match the entries inGroup I with the enzymes inGroup II.
Group I Group II P. NAD$^+$ 1. Glutathione peroxidase Q. Selenium 2. Nitrogenase R. Pyridoxal phosphate 3. Lactate dehydrogenase S. Molybdenum 4. Glycogen phosphorylase Determine the correctness or otherwise of the following Assertion (a) and the Reason (r)
Assertion: A very low amount of inhibitor can act as an activator for allosteric enzymes.
Reason: Allosteric enzymes follow Michaelis-Menten kinetics.
