A. DNA release
B. Cleavage and opening of gate
C. Rejoining of cleaved strand
D. Strand passage
Choose the correct answer from the options given below :
Understanding Type I Topoisomerase DNA Relaxation Mechanism
Type I topoisomerases function to relax supercoiled DNA by transiently breaking and rejoining one DNA strand. This process involves several key steps performed in a specific order.
Sequence of DNA Relaxation
The mechanism proceeds as follows:
- B. Cleavage and opening of gate: The enzyme initially binds to the DNA and introduces a temporary single-strand break (nick). This cleavage event allows the enzyme to create an opening or 'gate' in the DNA backbone.
- D. Strand passage: Through this gate, the intact, opposite DNA strand passes. This passage alters the DNA's topological state.
- C. Rejoining of cleaved strand: Following the passage of the intact strand, the enzyme reseals the nicked DNA strand, restoring the phosphodiester backbone.
- A. DNA release: Finally, the type I topoisomerase detaches from the DNA molecule, leaving it in a relaxed state.
Therefore, the correct sequence representing the action of type I topoisomerase in DNA relaxation is B → D → C → A.
Similar Questions
- The ability of a malignant cell to detach itself from a tumor and establish a new tumor and another site within the host :
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Cells of different tissues essentially require $CO_2$ to generate energy and perform metabolic functions.
Reason (R) : Deficiency of oxygen or hypoxia results in failure to carry metabolic functions.
In the light of the above statements, choose the most appropriate answer from the options given below : - Depending upon the antigen how much lag period is required for memory B cell after antigen administration.
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The conduction in the Atrio-ventricular (AV) node is slow i.e. 0.05 m/sec, there is a delay of approx. 0.1 second before excitation spreads to the ventricles.
Reason (R) : AV node delay enables the atria to empty the blood present within them into the ventricles before these contract.
In the light of the above statements, choose the most appropriate answer from the options given below : - Choose the correct sequence of the structure of the ear starting from external ear (entry of sound) to inner ear.
A. Helix
B. Oval window
C. Pinna
D. Cochlae
E. Tympanic membrane
Choose the correct answer from the options given below : - The correct order of systemic circulation in a heart :
A. Aorta
B. Aortic valve
C. Left ventricle
D. Superior and inferior venae cavae
E. Right atrium
Choose the correct answer from the options given below : - Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Lysosomes are called suicidal bags.
Reason (R) : When a cell dies, lysosomal enzymes cause autolysis of the remanant.
In the light of the above statements, choose the most appropriate answer from the options given below : - Which of the following wavelength (nm) correspond to visible range of humans ?
A. 20 nm
B. 200 nm
C. 400 nm
D. 600 nm
E. 900 nm
Choose the correct answer from the options given below : - Which of the following advantages of chemiluminescence technology are true :
A. Low cost
B. Non linearity
C. Stability
D. Sensitivity
Choose the correct answer from the options given below : - When the number of frequencies are put in a cell in a contingency table, the degree of freedom will be _________.
Important Questions from Mixed Topic (CUET PG)
- Who was the founder of Bolshevik Communist party?
- What is the key guide to statecraft in the realist tradition?
- Chronologically arrange the events in the Cold War period.
A. Berlin Wall is constructed
B. Communist China joins the UN
C. Soviet invasion of Czechoslovakia
D. Berlin Blockade
Choose the correct answer from the options given below: Morgenthau's principles of political realism are:
A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
C. International Politics is an arena of conflicting self-interests
D. The ethics of international relations is situational ethics which is very different from private morality
Choose the correct answer from the options given below:Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?
