**Question:** True about DNA polymerase in eukaryotes: (PGI June 2008)

A. DNA polymerase is responsible for synthesizing DNA in eukaryotes
B. DNA polymerase can only add nucleotides to the 3' end of the DNA strand
C. DNA polymerase can work independently without any other enzymes
D. DNA polymerase is absent in the nucleus of eukaryotic cells

**Correct Answer:** **B. DNA polymerase can only add nucleotides to the 3' end of the DNA strand.**

**Core Concept:** DNA polymerase is an essential enzyme involved in DNA replication and repair processes in eukaryotic cells. It plays a crucial role in maintaining the genetic material and passing it on to the next generation of cells. In the context of this question, we need to understand the role of DNA polymerase in eukaryotes, particularly focusing on its ability to add nucleotides.

**Why the Correct Answer is Right:** DNA polymerase, particularly eukaryotic DNA polymerase, is a processive enzyme responsible for synthesizing DNA in eukaryotic cells. It plays a vital role in replication and repair processes, ensuring the accurate replication of the genetic material.

**Why Each Wrong Option is Incorrect:**

A. While DNA polymerase is indeed involved in DNA synthesis in eukaryotes, the statement that it is responsible for synthesizing DNA in the entire cell is incorrect. DNA polymerase works in conjunction with other enzymes and cellular processes to ensure accurate replication of DNA.

C. DNA polymerase is a processive enzyme, meaning it maintains a continuous synthesis of the DNA strand, but it does not work independently without other enzymes and cellular components. It requires various factors to facilitate and regulate its function.

D. Although DNA polymerase is present in the nucleus, the statement that it is absent in eukaryotic cells is incorrect. DNA polymerase is essential for DNA replication in the nucleus and plays a crucial role in maintaining genetic information.

**Clinical Pearl:** Understanding the role of DNA polymerase in eukaryotic cells is essential for medical students and clinicians, as it directly relates to genetic information maintenance, replication, and repair processes. This knowledge is crucial for diagnosing and treating genetic disorders and understanding the mechanisms of drug action and resistance.