Question

Explain what would happen during DNA replication if both DNA Pol I and DNA Pol III had high processivity.

Answer 1

Role of DNA polymerase I –

a) Hydrolyse the RNA primer

b) Fill the gaps with complementary deoxyribonucleoside triphosphates

c) End the DNA replication

Role of DNA polymerase III–

a) Select and add free deoxyribonucleoside triphosphates to DNA template

b) Catalyze phosphodiester bonds between deoxyribonucleotides.

c) Proofreads each deoxyribonucleotide and add it to the growing strand and removes mismatched deoxyribonucleotide.

In general, the processivity of a polymerase enzyme is determined as number of nucleotides added into DNA during a single template-binding event before the dissociation of DNA template.

With high processivity, all the above functions of DNA polymerase I and III will occur at a higher pace thereby leading to addition of high number of nucleotides to DNA, thereby yielding larger DNA molecule and faster completion of DNA replication