What is the role of the AT rich regions in initiation of DNA replication quizlet?

What is the role of the AT rich regions in initiation of DNA replication quizlet?

DNA replication is initiated by the binding of DnaA proteins to sequences within the origin known as DnaA box sequences. Following separation of the AT-rich region, the DnaA proteins, with the help of DnaC proteins, recruit DNA helicase proteins to this site. DNA helicase is also known as DnaB protein.

What is the significance of the AT rich region within the Tandem 13 mer sequence in oriC?

What is the significance of the AT rich region within the tandem 13-mer sequence in OriC? DNA polymerase III is able to remove RNA primers due to its 5′ to 3′ exonuclease activity. DNA replication occurs in a 3′-5′ direction in both the leading and lagging strands.

What is at rich DNA?

The AT-rich DNA is mostly associated with condensed chromatin, whereas the GC-rich sequence is preferably located in the dispersed chromatin. The AT-rich genes are prone to be tissue-specific (silenced in most tissues), while the GC-rich genes tend to be housekeeping (expressed in many tissues).

Why is an AT rich region part of the E coli oriC?

Why is an AT rich region part of the E. coli oriC? A) DnaA proteins bind to AT rich sites. DnaC proteins bind to AT rich sites.

How many origin of replication are present in the E coli genome?

E. coli has a single circular chromosome that is ~4.6 megabases in length, containing a single origin of replication (oriC). The two major cis-acting features of the ~250 bp oriC are an AT-rich DNA unwinding element (DUE) and multiple 9 bp DnaA-binding motifs (Skarstad and Katayama, 2013).

What are the 4 key players in DNA replication?

Terms in this set (5)

• DNA polymerase III. leading and lagging strand synthesis.
• Ligase. seals the nick in the phosphodiester bond between two Okazaki fragments.
• Helicase. breaking the hydrogen bond between nitrogenous bases, generating single stranded DNA templates.
• Topoisomerase.
• Primase.

Why do multiple replication bubbles form?

A replication bubble is an unwound and open region of DNA where DNA replication occurs. Bubbles are created when the enzyme helicase separates the two strands of DNA so that they can be replicated. DNA polymerase is an enzyme that adds complementary base pairs to create new partner strands for the original DNA strands.

What happens when two growing replication bubbles run into each other?

Replication takes place on both strands at each end of the bubble, with the two replication forks spreading outward. Eventually, the replication forks of adjacent replicons run into each other, and the replicons fuse to form long stretches of newly synthesized DNA.

How many replication bubbles do prokaryotes have?

All prokaryotes have circular DNA which replicates from a single origin, resulting in a single replication bubble. The replication bubble grows in two directions from its origin. There are two replication forks in a replication bubble, which is where the parental DNA double helix is split.

How does DNA replication occur in prokaryotes?

DNA Replication in Prokaryotes: A replication fork is formed when helicase separates the DNA strands at the origin of replication. DNA ligase seals the gaps between the Okazaki fragments, joining the fragments into a single DNA molecule. The replication fork moves at the rate of 1000 nucleotides per second.