Read the sentence and answer the questions 

The process of replication requires a set of catalyst (enzymes). The main enzyme is referred to as DNA dependent DNA Polymerase. E.Coli that has only 4.6x10⁶ bp (compare it with human whose diploid content is 6.6x10⁶ bp), completes the process of replication within 18 minutes, that means the average rate of polymerisation has to be approximately 2000 bp per second these polymerase also have catalyse the reaction with high degree of accuracy. Deoxyribonucleoside triphophates serve dual purposes. In addition to DNA dependent DNA polymerases, many additional enzymes are required to complete the process of
replication with high degree of accuracy. For long DNA molecules, since the two strands of DNA cannot be separated in its entire length ( due to very high energy requirement), the replication occur with in a small opening of the DNA helix, referred to as replication fork. The DNA-dependent DNA polymerase catalyse polymerisation only in one direction. that is 5'-3'. This creates some additional complications at the replicating fork. Consequently, on one strand (the template with polarity 3'—5') the replication is continuous, which on the others (the template with polarity 5'—3}). it is the discontiuous. The non-continuously synthesized fragments are later joined by the enzyme DNA ligase.


Which of the following statements are correct?

A. DNA dependent DNA polymerase is a slow catalyst

B. Deoxyribonucleoside triphosphate  not provide energy for polymerisation

C. Replication fork is a small opening of the DNA helix

D. The replication is discontinuous on DNA template with polarity 3'-5'

E. The replication is continuous on DNA template with polarity 3'-5'

Choose the correct answer form the options given below:

C  and E only

The correct answer is Option (4) -C  and E only

The main enzyme is referred to as DNA-dependent DNA polymerase, since it uses a DNA template to catalyse the polymerisation of deoxynucleotides.

These enzymes are highly efficient enzymes as they have to catalyse polymerisation of a large number of nucleotides in a very short time.

E. coli that has only 4.6 ×106 bp (compare it with human whose diploid content is 6.6 × 109 bp), completes the process of replication within 18 minutes; that means the average rate of polymerisation has to be approximately 2000 bp per second.

 Deoxyribonucleoside triphosphates serve dual purposes. In addition to acting as substrates, they provide energy for polymerisation reaction (the two terminal phosphates in a deoxynucleoside triphosphates are high-energy phosphates, same as in case of ATP).

The replication occur within a small opening of the DNA helix, referred to as replication fork. The DNA-dependent DNA polymerases catalyse polymerisation only in one direction, that is 5'-3'.

This creates some additional complications at the replicating fork. Consequently, on one strand (the template with polarity 3'-5'), the replication is continuous, while on the other (the template with polarity 5'-3'), it is discontinuous.

The discontinuously synthesised fragments are later joined by the enzyme DNA ligase.