Difference Between Prokaryotic and Eukaryotic Topoisomerase

The key difference between prokaryotic and eukaryotic topoisomerase is the cellular origin of the topoisomerase. Prokaryotic topoisomerases are present in the cells of prokaryotic cellular origin while eukaryotic topoisomerases are present among organisms with eukaryotic cellular origin.

1. Do prokaryotes have topoisomerase?
2. What happens if topoisomerase is not functional in prokaryotes?
3. What is the role of topoisomerase in eukaryotic DNA replication?
4. What is the difference between prokaryotic and eukaryotic DNA replication?
5. What is the difference between topoisomerase 1 and 2?
6. What does Supercoiling mean?
7. What happens if no topoisomerase?
8. Which enzyme is a topoisomerase?
9. Is the enzyme responsible for Supercoiling?
10. How do topoisomerases work?
11. What are Okazaki fragments?
12. What do the enzymes topoisomerase I and topoisomerase II have in common?

Do prokaryotes have topoisomerase?

In contrast with eukaryotic topoisomerases that act similarly on positively and negatively supercoiled DNA, prokaryotes have two type-II topoisomerases: DNA gyrase and topoisomerase (Topo) IV, which act differently on (+) and (–) supercoiled DNA [respectively, left-handed (L-) and right-handed (R-) nodes; see Fig. 1a].

What happens if topoisomerase is not functional in prokaryotes?

In cells lacking the activity of topoisomerase I the chromosomal DNA becomes hypernegatively supercoiled, especially behind transcribing RNAP complexes. DNA gyrase will remove the positive torsional stress in front of RNAP, whereas the negative supercoils will persist if they cannot be relaxed by Topo I.

What is the role of topoisomerase in eukaryotic DNA replication?

Among the proteins involved in DNA replication are several that change the topology of DNA: helicases, which can unwind the DNA duplex, thereby inducing formation of supercoils, and topoisomerases, which catalyze addition or removal of supercoils.

What is the difference between prokaryotic and eukaryotic DNA replication?

Both prokaryotic and eukaryotic DNA undergo replication by the enzyme DNA polymerase. The main difference between prokaryotic and eukaryotic DNA is that prokaryotic DNA is found in the cytoplasm whereas eukaryotic DNA is packed into the nucleus of the cell.

What is the difference between topoisomerase 1 and 2?

Topoisomerase I refers to the enzymes which cut one of the two strands of double-stranded DNA, relax the strand, and reanneal the strand while topoisomerase II refers to the enzymes which cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils.

What does Supercoiling mean?

Supercoils refer to the DNA structure in which double-stranded circular DNA twists around each other. This is termed supercoiling, supertwisting or superhelicity -- meaning the coiling of a coil, also understood in terms of knots.

What happens if no topoisomerase?

Topoisomerase alleviates supercoiling downstream of the origin of replication. In the absence of topoisomerase, supercoiling tension would increase to the point where DNA could fragment. DNA replication could not be initiated because there would be no RNA primer. DNA strands would not be ligated together.

Which enzyme is a topoisomerase?

Topoisomerases are isomerase enzymes that act on the topology of DNA.
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Topoisomerase.

Is the enzyme responsible for Supercoiling?

Topoisomerase. Topoisomerases are enzymes that are responsible for the introduction and elimination of supercoils. Positive and negative supercoils require two different topoisomerases.

How do topoisomerases work?

Topoisomerase I is a ubiquitous enzyme whose function in vivo is to relieve the torsional strain in DNA, specifically to remove positive supercoils generated in front of the replication fork and to relieve negative supercoils occurring downstream of RNA polymerase during transcription.

What are Okazaki fragments?

Okazaki fragments are short sequences of DNA nucleotides (approximately 150 to 200 base pairs long in eukaryotes) which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication.

What do the enzymes topoisomerase I and topoisomerase II have in common?

What do the enzymes topoisomerase I and topoisomerase II have in common? They both have nuclease activity. They both create double-strand DNA breaks. ... They both can create winding (tension) in an initially relaxed DNA molecule.