DNA Synthesis and Cell cycle Flashcards
Understand and apply the complex reactions that take place during DNA Synthesis and how this affects the average somatic cell cycle. (26 cards)
The ability for DNA polymerase to ‘proof read’ is called what?
Mismatch repair system
Name the enzyme key for DNA replication
DNA Polymerase
Gene replication must happen before what stage in the cell cycle?
Mitosis
What are okazaki fragments?
Fragments found on the lagging strand of DNA replication.
Why can the leading stranded be copied directly?
Because the direction is from 5” to 3”
In what direction does the DNA Polymerase work?
From the 5” Primer end towards the 3” End
What is the role of DNA Gyrase?
Stops unwound single DNA strands from tangling by a breaking and rejoining mechanism.
What is the term given to DNA replication that describes the maintenance of 1 part of the DNA strand in the daughter cell?
Semi-Conservative Replication
What is a replication bubble?
A ‘bubble’ that forms that allows the replication machinery to enter.
In order to initiate a new strand of DNA what is needed?
RNA primase, to make a short RNA primer (10-20 bases long)
What is the specific phase that DNA synthesis occurs?
Interphase (S phase)
What are the phases of the cell cycle?
G1, G2, S phase, M Phase, G0
What apart from key enzymes are required for the replication of DNA?
Mg 2+, and Free nucleotide bases
What is a codon
A triplet code that codes for one amino acid
Explain briefly how the lagging stranded is copied
Copied in small pieces (Okazaki fragments) Each primed with RNA. When DNA polymerase encounters the RNA of a previously made fragment a RNase H removes the RNA and DNA polymerase replaces it with DNA.
DNA replication inhibitors can be used for what?
Antbacterial, antitumour and antiviral agents (Examples include, Gyrase inhibitors, Topo II inhibitors and reverse transcriptase.)
What is the replication origin?
The specific location on the DNA that DNA replication is initiated.
What is the role of DNA helicase
Unwind the helical Double-stranded DNA.
What is the difference in replication origins between prokaryotic and eukaryotic cells?
Prokaryotic DNA only has one replication origin, but Eukaryotes can have many.
What are phases of mitosis?
Prophase, Prometaphase Metaphase, Anaphase, Telophase
What are the components of a nucleotide base?
Deoxyribose (DNA) Ribose sugar (RNA) Nitrogenous base and a phosphate group.
What enzyme joins the two adjacent okazaki fragments together?
DNA Ligase
Cytosine binds to Guanine via how many hydrogen bonds?
Three
Name two factors that can damage DNA
UV light and Chemical agents
