Topoisomerases

What are the two main types of topoisomerases?

• Type II and Type IV topoisomerases

• Type I and Type II topoisomerases

• Type I and Type III topoisomerases

• Type A and Type B topoisomerases

What role do topoisomerases play during DNA replication?

• Topoisomerases repair DNA damage after replication.

• Topoisomerases act as helicases to unwind DNA.

• Topoisomerases synthesize new DNA strands during replication.

• Topoisomerases relieve torsional strain and prevent supercoiling during DNA replication.

Explain the difference between Type I and Type II topoisomerases.

• Type I topoisomerases are involved in DNA replication, while Type II topoisomerases are not.

• Type I topoisomerases only unwind DNA, while Type II topoisomerases only rewind it.

• Type I topoisomerases cut both strands of DNA, while Type II topoisomerases cut one strand.

• Type I topoisomerases cut one strand of DNA, while Type II topoisomerases cut both strands.

How do topoisomerases relieve torsional strain in DNA?

• Topoisomerases relieve torsional strain by introducing temporary breaks in DNA strands, allowing them to unwind or relax.

• Topoisomerases add extra twists to DNA strands to increase tension.

• Topoisomerases permanently cut and splice DNA to stabilize it.

• Topoisomerases bind to DNA and prevent any movement to maintain structure.

Topoisomerase I catalyzes which type of reaction?

• Double-stranded DNA cleavage

• Single-stranded DNA nicking and closing

• ATP-dependent double-strand break

• Removal of histone proteins from chromatin

Which of the following is NOT a function of topoisomerase?

• Formation of DNA supercoils

• Decatenation of intertwined DNA molecules

• • Unwinding of RNA during transcription.

• Untangling of replicated chromosomes

What is the major difference between Type I and Type II topoisomerases?

• Type I introduces double-strand breaks, while Type II introduces single-strand breaks.

• Type I requires ATP, while Type II does not.

• Type II cuts one strand of DNA, while Type I cuts both strands of DNA.

• None

Which of the following processes would NOT be affected by the inhibition of topoisomerase II?

• Decatenation of replicated chromosomes.

• DNA transcription.

• mRNA splicing.

• DNA recombination.

Which of the following statements is true regarding the mechanism of topoisomerase I?

• It breaks both strands of DNA.

• It uses ATP hydrolysis to relax supercoiled DNA.

• It introduces positive supercoils.

• It allows the rotation of the cut strand around the intact one.

Which of the following statements is true regarding the mechanism of topoisomerase I?

• It breaks both strands of DNA.

• It uses ATP hydrolysis to relax supercoiled DNA.

• It introduces positive supercoils.

• It allows the rotation of the cut strand around the intact one.