Biochemistry 200 2
Terms
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- What is semiconservative DNA replication?
- Each new piece of DNA has one of the original parents strands, combined with one new daughter strand
- What is conservative DNA replication?
- The two parental strands remain together and the daughter strands are together.
- How can you tell what kind of replication has occured?
- Density gradient ultracentrifugation... basically put it in a centrifuge and indentify based on weight
- What are replication forks?
- the current site where DNA is undergoing replication
- In prokaryotic DNA, replication is _____ with ____ point(s) of origin
- bidirectional, 2
- In Eukaryotic DNA, replication is _____ and has ____ point(s) of origin
- bidirectional, multiple
-
DNA polymerase only works from the ___ end to ___
It can not replicate from ___ to ___ -
5' to 3'
3' to 5' - Describe how DNA polymerase I is related to Okazaki fragments
- DNA polymerase can only replicate 5' to 3'. Therefore, when it has to replicate the strand going 5' to 3' it has to start near the replication fork and form backwards. It then has to jump back when more is available as the other strand is replicated. These segments are called Okazaki (lagging) strands
- what three things does DNA polymerase I require to function?
- A single stranded template, a primer with an open 3' OH and a complimentary deoxynucleoside triphosphate
- What is helicase?
- Begins the unwinding of DNA
- What is DNA gyrase
- A topoisomerase that relieves supercoiling
- What is primase?
- It synthesizes the RNA primer that is needed to start DNA replication
- What is DNA polymerase III's function?
- To elongate the chain by DNA synthesis
- What is DNA polymerase I's function?
- It removes the RNA primer and adds DNA to the strand
- What is DNA ligase?
- it closes the last phosphodiester gap
- DNA synthesis in prok. is ___ directional
- bi
- The leading strand in DNA replication forms continuosly or non continuosly?
- continuously
- The lagging strand in DNA forms cont. or discont?
- Discont (Okazaki fragments)
- How are Okazaki fragments joined?
- By DNA polymerase I and ligase
- What unwinds DNA?
- Helicase
- _____ relieves supercoiling
- DNA gyrase
- What generates the RNA primer required by DNA polymerase I for DNA replication?
- Primase
- In Euk. cells, there are ____ points of origin
- Multiple
- In Euk. DNA, there in unpacking and repacking of ____
- chromatin
- In Euk. Cells, DNA polymerase sigma is equivalent to _____ in prok. cells
- DNA polymerase I, by adding DNA nad working on both strands independently
- in Euk. cells, what is the RNA primer degraded by, instead of DNA polymerase I in Prok. cells
- FEN-1 and RNase H1
- What is a telomere?
- This is a quadruplex DNA conformation (kind of a folding) that occurs are the ends of DNA to keep the RNA primer from falling off.
- What are SSB?
- single strand binding proteins; they facilitate polymerase binding in prok cells
- in Euk Cells, what plays the DNA polymerase role of creating primers?
- polymerase alpha