Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Molecular Basis of Inheritance

Question:

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.

In E. Coli the main enzyme required to catalyze the polymerisation of deoxynucleotide is __________

Options:

DNA- Dependent DNA Polymerase

DNA- Dependent RNA Polymerase

RNA- Dependent DNA Polymerase

RNA- Dependent RNA Polymerase

Correct Answer:

DNA- Dependent DNA Polymerase

Explanation:

The correct answer is Option (1) -DNA- Dependent DNA Polymerase

In living cells, such as E. coli, the process of replication requires a set of catalysts (enzymes). 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.