DNA Polymerase III

Definition

DNA polymerase III is the primary enzyme responsible for the replication of DNA during the process of cell division. It is a highly accurate and efficient enzyme that plays a crucial role in ensuring the faithful duplication of genetic information as cells divide and proliferate.

5 Must Know Facts For Your Next Test

1. DNA polymerase III is a large, multi-subunit enzyme complex that coordinates the replication of both the leading and lagging strands of DNA.
2. The enzyme has a high fidelity, with an error rate of only about 1 in 100,000 nucleotides, ensuring the accurate duplication of genetic information.
3. DNA polymerase III is capable of synthesizing DNA at a rate of up to 1,000 nucleotides per second, making it one of the fastest known enzymes.
4. The enzyme requires a DNA template, a free 3' hydroxyl group, and deoxynucleotide triphosphates (dNTPs) as substrates to carry out DNA synthesis.
5. DNA polymerase III works in coordination with other proteins, such as helicase and primase, to ensure the efficient and coordinated replication of the entire genome.

Review Questions

• Describe the role of DNA polymerase III in the process of DNA replication.
  • DNA polymerase III is the primary enzyme responsible for the replication of DNA during cell division. It is a highly accurate and efficient enzyme that coordinates the synthesis of both the leading and lagging strands of the DNA molecule. DNA polymerase III requires a DNA template, a free 3' hydroxyl group, and deoxynucleotide triphosphates (dNTPs) as substrates to carry out DNA synthesis. The enzyme works in conjunction with other proteins, such as helicase and primase, to ensure the faithful duplication of the entire genome.
• Explain the importance of the high fidelity of DNA polymerase III in maintaining genetic integrity.
  • The high fidelity of DNA polymerase III, with an error rate of only about 1 in 100,000 nucleotides, is crucial for maintaining the genetic integrity of the cell. By accurately duplicating the DNA, the enzyme ensures that the genetic information is faithfully passed on to daughter cells during cell division. This high level of accuracy helps to prevent the accumulation of mutations that could lead to genetic disorders, cancer, or other detrimental effects on the organism.
• Analyze the coordination between DNA polymerase III and other proteins involved in the DNA replication process.
  • DNA polymerase III does not work in isolation but rather as part of a larger complex of proteins that collectively ensure the efficient and coordinated replication of the entire genome. The enzyme works in tandem with helicase, which unwinds the double-stranded DNA molecule, creating a replication fork where DNA polymerase III can initiate replication. Primase also plays a crucial role by synthesizing short RNA primers, which provide a starting point for DNA polymerase III to begin DNA synthesis on the lagging strand. The coordination and integration of these various proteins and enzymes is essential for the rapid and accurate duplication of the genetic material during cell division.

Related terms

DNA Replication:

The process by which a DNA molecule is copied, ensuring that genetic information is faithfully passed on to daughter cells during cell division.

Helicase:

An enzyme that unwinds the double-stranded DNA molecule, creating a replication fork where DNA polymerase III can initiate replication.

Primase: An enzyme that synthesizes short RNA primers, which provide a starting point for DNA polymerase III to begin DNA synthesis on the lagging strand.