DNA Replication Flashcards
What is DNA replication, and why is it essential for living organisms?
DNA replication is the process of making an exact copy of DNA, crucial for reproduction, growth, and tissue replacement.
How does DNA replication help in growth and tissue replacement in multicellular organisms?
It generates new cells with identical DNA, allowing growth and replacement of damaged cells.
What does the term “semiconservative” mean in DNA replication?
Each new DNA molecule has one original and one newly synthesized strand, preserving genetic information.
How did Meselson and Stahl’s experiments support the semiconservative model?
Their experiments showed that after replication, each DNA molecule had one old and one new strand.
What is the replication fork in DNA replication?
The replication fork is the Y-shaped region where DNA is unwound and new strands are synthesized.
What does DNA helicase do during DNA replication?
DNA helicase unwinds the DNA double helix by breaking hydrogen bonds between strands.
What is the role of DNA polymerase in DNA replication?
DNA polymerase synthesizes new DNA strands by adding nucleotides to the template strand.
What is a primer in DNA replication?
A primer is a short RNA or DNA strand that provides a starting point for DNA synthesis.
In which direction does DNA polymerase move along the template strand?
DNA polymerase moves 3’ to 5’ on the template strand and synthesizes the new strand 5’ to 3’.
What is the role of restriction enzymes in gel electrophoresis?
Restriction enzymes cut DNA at specific sequences, generating fragments for analysis.
How does gel electrophoresis separate DNA fragments?
DNA fragments move through a gel, with smaller fragments traveling faster than larger ones.
What are two main uses of DNA profiling by electrophoresis?
DNA profiling is used in forensic identification and paternity testing.
What are other names for DNA profiling?
DNA fingerprinting, DNA typing, and genetic fingerprinting.
What is the purpose of PCR in labs?
PCR amplifies small DNA samples, creating enough for analysis.
What cellular process does PCR mimic?
PCR mimics DNA replication, specifically DNA synthesis.
Why are high temperatures used in PCR?
High temperatures denature DNA, separating the strands for replication.
How does complementary base pairing work in PCR?
Complementary base pairing ensures primers bind to the correct DNA template, guiding DNA synthesis.
Why is PCR called a chain reaction?
PCR exponentially increases DNA copies, doubling each cycle.
What process amplifies small amounts of DNA for profiling?
PCR (Polymerase Chain Reaction) amplifies DNA for profiling.
What happens if DNA polymerase III is missing during DNA replication?
DNA replication won’t occur as DNA polymerase III is needed to synthesize the new DNA strand.
What does DNA gyrase do in DNA replication?
DNA gyrase relieves supercoiling strain ahead of the replication fork.
What causes “naked” DNA in prokaryotes?
Prokaryotes lack a nucleus, so their DNA is directly exposed in the nucleoid region.
What causes mistakes during DNA replication?
Errors can occur due to spontaneous base pairing mistakes, DNA damage, or polymerase errors.
How are replication mistakes corrected?
Proofreading by DNA polymerase and mismatch repair enzymes correct errors.
