Replication

Definition

Replication is the biological process by which a cell duplicates its DNA before cell division, ensuring that each daughter cell receives an exact copy of the genetic material. This process is vital for growth, development, and maintenance of all living organisms, as it ensures genetic continuity and plays a key role in heredity and evolution.

5 Must Know Facts For Your Next Test

1. Replication occurs during the S phase of the cell cycle, which precedes mitosis and meiosis.
2. The process begins at specific locations on the DNA molecule known as 'origins of replication'.
3. Replication is bidirectional, meaning that it proceeds in two directions from each origin, creating replication forks.
4. Errors during replication can lead to mutations, which may have significant effects on an organism's traits or health.
5. The accuracy of replication is increased by proofreading mechanisms employed by DNA polymerases that can correct mistakes during synthesis.

Review Questions

• How does the structure of DNA facilitate its replication?
  • The double helix structure of DNA allows for easy separation of the two strands, making it possible for enzymes to access the genetic code during replication. The complementary base pairing ensures that each new strand is an exact copy of the original strand. The antiparallel orientation of the strands also contributes to the directionality of replication, requiring different mechanisms for synthesizing leading and lagging strands.
• Discuss the roles of DNA polymerase and Okazaki fragments in the replication process.
  • DNA polymerase is crucial for synthesizing new DNA strands by adding nucleotides to a growing chain based on the template strand. On the lagging strand, replication occurs discontinuously, resulting in the formation of Okazaki fragments. These fragments are short sequences of newly synthesized DNA that are later joined together by another enzyme, DNA ligase, to create a continuous strand.
• Evaluate the implications of errors in DNA replication for genetic diversity and evolution.
  • Errors during DNA replication can result in mutations, which introduce genetic variation into populations. While many mutations are neutral or harmful, some can confer advantages that enhance survival and reproduction. This variation is essential for natural selection, driving evolutionary change over time. Thus, while fidelity in replication is crucial for maintaining genetic integrity, occasional errors can contribute to the adaptive potential of a species.

Related terms

DNA Polymerase:

An enzyme that synthesizes new strands of DNA by adding nucleotides complementary to the template strand during replication.

Semiconservative Replication:

The method of DNA replication in which each new DNA molecule consists of one original strand and one newly synthesized strand.

Okazaki Fragments:

Short sequences of DNA synthesized on the lagging strand during replication, which are later joined together by DNA ligase.