During replication of DNA, which one of the following enzymes polymerizes the Okazazki fragments?
**Core Concept**
DNA replication involves the unwinding of double-stranded DNA, followed by the synthesis of new complementary strands. Okazaki fragments are short, discontinuous DNA segments synthesized on the lagging strand during replication. These fragments require additional processing to form a continuous strand.
**Why the Correct Answer is Right**
The Okazaki fragments are synthesized by the enzyme DNA polymerase delta (Pol δ), which is specifically responsible for synthesizing the lagging strand. Pol δ uses its 5' to 3' exonuclease activity to remove RNA primers and fill in the gaps, eventually forming a continuous strand. This process involves the coordination of several enzymes and factors, including DNA ligase, which seals the gaps between Okazaki fragments.
**Why Each Wrong Option is Incorrect**
* **Option A:** DNA polymerase alpha (Pol α) is responsible for initiating DNA synthesis by adding short RNA primers to the template strands, but it is not the primary enzyme for synthesizing Okazaki fragments.
* **Option B:** DNA ligase is an essential enzyme in the process of sealing the gaps between Okazaki fragments, but it does not polymerize the fragments themselves.
* **Option D:** DNA polymerase epsilon (Pol ε) is another enzyme involved in DNA replication, but it is primarily responsible for leading strand synthesis, not Okazaki fragment synthesis.
**Clinical Pearl / High-Yield Fact**
DNA polymerase delta's role in Okazaki fragment synthesis is crucial for maintaining genomic integrity. Inhibition of Pol δ can lead to genetic instability and contribute to the development of various diseases.
**Correct Answer:** C. DNA polymerase delta (Pol δ)