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dna replication
A LevelBiology~4 min read
Overview
DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. This semi-conservative process ensures that genetic information is accurately passed from one generation of cells to the next, crucial for cell division and organismal growth.
Introduction to DNA Replication
DNA replication is a fundamental process in all living organisms, ensuring the accurate transmission of genetic information during cell division. It occurs during the S phase of the cell cycle. The process is described as **semi-conservative**, meaning that each new DNA molecule produced consists of...
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Key Concepts
- Semi-conservative replication: Each new DNA molecule consists of one original (template) strand and one newly synthesized strand.
- Replication fork: The Y-shaped region where the DNA double helix is unwound and new DNA strands are synthesized.
- Leading strand: The new DNA strand synthesized continuously in the 5' to 3' direction, towards the replication fork.
- Lagging strand: The new DNA strand synthesized discontinuously in short fragments (Okazaki fragments) in the 5' to 3' direction, away from the replication fork.
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Exam Tips
- →Clearly distinguish between the roles of different enzymes (helicase, primase, DNA polymerase I, DNA polymerase III, ligase, gyrase). A common mistake is confusing their functions.
- →Be able to draw and label a replication fork, indicating the leading and lagging strands, direction of synthesis, Okazaki fragments, and the positions of key enzymes.
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