3.1.5.2 Replication of DNA Flashcards
Q: What is the main feature of semi-conservative DNA replication?
A: Each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
Q: What happens during the unwinding of the DNA double helix?
A: The two strands of the DNA molecule are separated, allowing each strand to act as a template for new strand synthesis.
Q: What role does DNA helicase play in DNA replication?
A: DNA helicase unwinds the double helix and breaks the hydrogen bonds between complementary bases, separating the two strands.
Q: How are hydrogen bonds involved in DNA replication?
A: Hydrogen bonds between complementary bases (A-T and G-C) are broken by DNA helicase to separate the strands during replication.
Q: What is the role of new DNA nucleotides in replication?
A: New DNA nucleotides are attracted to the exposed bases on the template strands and base pair according to complementary base pairing rules (A with T, G with C).
Q: How does DNA polymerase contribute to DNA replication?
A: DNA polymerase catalyzes the condensation reaction that joins adjacent nucleotides on the new strand, forming a phosphodiester bond between them.
Q: Describe the process of base pairing during DNA replication.
A: Free DNA nucleotides align with complementary bases on the template strand (A pairs with T, and G pairs with C) and are linked together by DNA polymerase.
Q: What is the significance of the Watson-Crick model in understanding DNA replication?
A: The Watson-Crick model provides the foundational structure of DNA and explains how the double helix can be replicated semi-conservatively with complementary base pairing.
Q: How did Meselson and Stahl’s experiment validate the semi-conservative model of DNA replication?
A: Their experiment used isotopic labeling to demonstrate that DNA replication results in one original and one newly synthesized strand in each new DNA molecule.
Q: Why is the semi-conservative model important for genetic continuity?
A: It ensures that each daughter cell receives an exact copy of the DNA, preserving genetic information across cell generations.
Q: What are the key steps in semi-conservative DNA replication?
A: 1) Unwinding of the double helix, 2) Breakage of hydrogen bonds between complementary bases, 3) Base pairing of new nucleotides, 4) Joining of nucleotides by DNA polymerase.
Q: What is the role of DNA polymerase in joining nucleotides?
A: DNA polymerase facilitates the formation of phosphodiester bonds between nucleotides, creating a continuous new strand.
