Question

Draw a diagram of a genome replication site in E. coli showing the location of the following components: Helicase; single stranded DNA binding protein; primer; DNA polymerase III; Okasaki fragment; leading strand and lagging strand.

Answer 1

Above picture shows the genomic replication site of E.coli

Each one does different functions.

Helicase:

DNA helicase is one of the enzyme which involved in unwinding the duplex DNA and forms a replication fork inorder to provide a single stranded template.

SSB protein:

In E.coli single strand binding protein is a tetramer binds to each of the single strands and inhibit them from reannealing.

Primer:

The primers used in replication process are short RNA molecules.It is synthesised with the help of enzyme Primase inorder to prime DNA chain elongation.And it helps in development of Okazaki fragments

DNA polymerase III:

It is considered as a primary enzyme which is involved in DNA replication process.It has 3'-5' exonuclease activity ( proof reading) so it avoids mismatch base addition during replication.It is a multiprotein subunit complex,each one does unique function.It carries out 5'-3' primer initiated polymerisation of DNA.

Leading strand:

In replication fork ,a single strand is continuously synthesised from a single primer molecule in 5'-3' direction.It is called leading strand.

Lagging strand:

One of the strand undergoes discontinuous synthesis because DNA polymerase can add polymerase to 3'emd of the primer.

Okazaki fragments:

In lagging strand the produced short pieces of DNA is called as Okazaki fragments.

Hope this helps you:)

DNA polymerase II Primase Prim U DNA helicase IVA Lagging strand Cokaz Primer icase Moven Single Stranded DNA binding Protein (SSB) Genome Replication site of E.coli