NEETZoologyMolecular Basis of Inheritance
Read the given statement and select the option that correctly fills the blanks (A) and (B). In E. coli, the main enzyme for DNA replication is (A), which catalyses the polymerisation of deoxynucleotides strictly in the (B) direction.
Options
- A(A) DNA-dependent RNA polymerase, (B) 5^ 3^
- B(A) DNA-dependent DNA polymerase, (B) 3^ 5^
- C(A) DNA-dependent DNA polymerase, (B) 5^ 3^
- D(A) DNA-dependent RNA polymerase, (B) 3^ 5^
Correct answer
C. (A) DNA-dependent DNA polymerase, (B) 5^ 3^
Step-by-step solution
In prokaryotes like E. coli, the process of DNA replication is mainly catalysed by the enzyme DNA-dependent DNA polymerase. This enzyme can catalyse polymerisation only in one direction, which is 5^ 3^ . DNA-dependent RNA polymerase is the main enzyme involved in transcription, not replication. The 3^ 5^ direction is the polarity of the template strand that is read continuously, not the direction of polymerisation. Answer: (A) DNA-dependent DNA polymerase, (B) 5^ 3^