Question

Mode of DNA replication in E coli is
A : Conservative and unidirectional
B: Semi conservative and unidirectional
C: Conservative and bidirectional
D : Semi conservative and bidirectional

Answer 1

Hint: E coli is a gram negative bacteria that normally lives in your intestine. It is commonly found in the lower intestine or gut of warm blooded animals. It is harmless and helps to keep the digestive tract healthy. It is rod shaped coliform bacteria. E coli replicates by copying the DNA complex and daughter duplex contains with one strand with new complementary partner.

Complete answer:
Escherichia coli is gram negative, rod shaped bacteria that normally lives in the alimentary canal.
It is a harmless bacteria which helps to keep the digestive tract healthy.
This type of bacteria is a single origin of replication on its chromosome.
Semiconservative replication means two original DNA strands separate during replications that is two strands of daughter DNA comes from single parent DNA. This is called a template strand.
By the help of enzyme helicase, the hydrogen bond between two strands nucleotides breaks.
Bidirectional replication takes in two directions: ’ −’ and ’−3’ directions. It leads to leading strands and lagging strands. The leading strands are most rapid and lagging strands are slower replication.
DNA replication in lagging strands are called okazaki fragments.
Conservative replication means two daughter DNA strands are formed from parents DNA and synthesize into two daughter strands.

Hence, the correct option is option D. Semiconservative and bidirectional.

Note:
The mode of replication of DNA in E coli is semi conservative and bidirectional. In semiconservative two strands of daughter DNA form from single parent DNA. Bidirectional replication takes place in two directions. Like other bacteria, the replication occurs in its chromosomes. The replication basically involves four phases. This bacteria has a capability of replicating very high that is approximately sixty to ninety minutes to segregate into chromosomes.