RR1 Flashcards
What are some problems encountered when storing information?
Limited physical space, degradation, errors when copying/translation
How long does DNA last as information carrier?
4 billion years
What first suggested that DNA uses a replication process?
Watson-Crick base pairs and double helix structure. Strands can be used as templates for the second one.
Where does the energy come from when binding new dNTPs.
From the bonds of the incoming phosphate group.
What does “semiconservative” mean when referring to DNA replication?
The obtained double stranded molecule contains one “old” strand from the parent and one newly synthesized strand.
How did we find out about DNA replication being semiconservative?
We studied a DNA molecule initially composed of a heavy isotope. Its environment only contained light isotope. After first replication cycle, the resulting molecule had one heavy strand and one light strand.
What’s a replication fork?
The opening of DNA duplex for replication to occur
What’s the purpose of DNA helicase?
Keep the two strands separated
What’s required for DNA Polymerization?
DNA polymerase // dNTPs // primer (DNA or RNA)
True or False? “DNA Polymerase can work using a naked template strand alone”
False. Needs a primer to give it a starting point.
True or False? “As the double helix is undone, a torsion force is generated onto the DNA strand”
True. It’s relieved by Topoisomerase (cuts a strand and connects it back.)
What’s the point of primase?
It’s an RNA polymerase that is trustworthy of creating a complementary RNA primer. (Other polymerase struggle with that first synthesis)
True or False? “Both new strands are synthesized from 5’ to 3’ in one go”
False. The leading strand is but the lagging strand is done in fragments (Okazaki) due to its inverse positioning.
Where do Okazaki fragments come from? How do they lead to DNA synthesis?
Primase creates an RNA primer that is elongated by DNA polymerase (1 Okazaki fragment). RNA is replaced by DNA. Adjoining DNA molecules are ligated by DNA ligase.
What’s the replisome?
Molecular machinery that carries out DNA replication (unwinding and synthesis)
