Is Theta replication unidirectional or bidirectional?

Theta replication is a type of DNA replication that occurs in prokaryotes (microorganisms that lack a nucleus and other membrane-bound organelles). It is characterized by the formation of a replication fork, in which the DNA double helix is unwound and each strand serves as a template for the synthesis of a new complementary strand. Theta replication is unidirectional, meaning that replication occurs in one direction from the origin of replication (the point at which replication begins) to the terminus (the point at which replication ends).

In contrast, eukaryotes (organisms with a nucleus and membrane-bound organelles) typically use bidirectional replication, in which replication forks form at multiple origins of replication and proceed in both directions along the chromosome. This allows for the simultaneous synthesis of both strands of the DNA molecule and allows for more efficient and accurate replication.

It is important to note that theta replication is not the only type of unidirectional replication. Other types of unidirectional replication include rolling circle replication, which occurs in some bacteria and viruses, and strand displacement replication, which occurs in some phages and plasmids.