DNA Replication

Definition

DNA replication is the biological process by which a cell makes an identical copy of its DNA, allowing genetic information to be passed on during cell division. This process is essential for the growth, repair, and reproduction of cells, ensuring that each daughter cell inherits the same genetic material as the parent cell. Accurate DNA replication is crucial for maintaining genetic stability and preventing mutations.

5 Must Know Facts For Your Next Test

1. DNA replication occurs during the S phase of the cell cycle, before a cell divides.
2. The process is semi-conservative, meaning each new DNA molecule consists of one original strand and one newly synthesized strand.
3. Replication begins at specific locations on the DNA molecule called origins of replication.
4. Leading strands are synthesized continuously, while lagging strands are synthesized in short segments due to the antiparallel nature of DNA.
5. DNA proofreading mechanisms help correct errors during replication to ensure high fidelity and minimize mutations.

Review Questions

• How does DNA replication ensure that genetic information is accurately passed from one generation of cells to the next?
  • DNA replication ensures accurate transmission of genetic information by employing a semi-conservative mechanism, where each new DNA molecule contains one original strand and one newly synthesized strand. This method reduces the risk of errors as complementary base pairing occurs between adenine and thymine, and between cytosine and guanine. Additionally, enzymes such as DNA polymerase proofread newly synthesized strands to correct any mistakes, further ensuring fidelity in genetic inheritance.
• Discuss the role of helicase and polymerase in the process of DNA replication.
  • Helicase plays a crucial role in DNA replication by unwinding the double helix structure, separating the two strands of DNA so that they can serve as templates for new strand synthesis. Once the strands are separated, DNA polymerase takes over to synthesize new strands by adding complementary nucleotides to the growing chain. Together, these enzymes coordinate their actions to ensure efficient and accurate DNA replication.
• Evaluate how errors in DNA replication can lead to mutations and potentially impact cellular function.
  • Errors during DNA replication can lead to mutations if they are not corrected by proofreading mechanisms or repair processes. Mutations can result in changes to amino acid sequences in proteins, potentially altering their function or rendering them nonfunctional. This can disrupt normal cellular processes and lead to diseases such as cancer, highlighting the importance of accurate DNA replication for maintaining cellular integrity and overall organism health.

Related terms

Helicase: An enzyme that unwinds the DNA double helix, separating the two strands to allow for replication.

Polymerase: An enzyme responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand during replication.

Okazaki Fragments: Short segments of DNA synthesized on the lagging strand during DNA replication, which are later joined together by DNA ligase.