Flashcards
Th2L02 DNA replication
Cards in this deck (28)
- 1What happens during G1 phaseSynthesis of protein components necessary to complete the cell cycle including histones, enzymes for replication, etc
- 2How long does G1 phase takeTakes 6-9 hours
- 3What are the three main steps of DNA replication• DNA unwinds
• Daughter strands of DNA produced from parent strand at replication fork
Semi conservation replication (each new DNA molecule contains one parent and one daughter strand) - 4What enzyme is able to separate the two strands of DNAhelicase
- 5Replication occurs in what direction along parent strand3' to 5'
- 6New daughter strand is formed in what direction5' to 3'
- 7What is the Leading strand and by what means does it replicateThe new continuous complementary DNA strand synthesised along the template strand in the mandatory 5' to 3' direction.
- 8What is the Lagging strand and by what means does it replicateA discontinuously synthesised DNA strand that elongates by means of Okazaki fragment
Each synthesised in a 5' to 3' direction away from the replication fork. - 9What are Okazaki fragmentsSmall fragments of DNA produced on the lagging strand during DNA replication
- 10How are Okazaki fragments joined togetherDNA ligase
- 11What is Single strand binding protein (SSB)Enzyme
Bind to and stabilize single strand of DNA until it can be used as a template
Prevents DNA from clamping shut - 12What is the function of pulling strands apartIncreases their winding about each other further down the molecule
- 13What is positive super-coilingCompensates for strand separation
- 14What is the role of DNA polymeraseadd nucleotides to pre-existing chains, making replication primed
- 15What is the role of primaseSynthesise short RNA stretches into primers so synthesis can begin without an existing DNA strand
- 16What is the role of DNA polymerase III• Extends the primers with DNA
NB: acts on lagging strand simultaneously and moves in the same direction as the replication fork - 17What is the role of DNA polymerase IRemoves the RNA, and replaces it with DNA leaving a gap between adjacent fragments
- 18What is the role of Topoisomerasecuts one or both strands of DNA to relieve the excess tension caused by the unwinding of the helix by helicase during replication (aka supercoils) preventing toxic DNA strand breakage
- 19What is the role of DNA ligaseSeals the gap between adjacent Okazaki fragments left by DNA polymerase I
- 20In what direction does DNA ligase work and what kind of bonds does it make• Makes 5' to 3' phosphodiester bond
Joining the adjacent fragments - 21What is the lagging strand templateLooped to coordinate leading/lagging strand synthesis so that replication occurs in the same direction (towards the inside of the fork)
- 22What is the sliding clampA protein that holds DNA polymerase III in place by tethering it to DNA
- 23How many replication origins are their per prokaryotic chromosomeOne
- 24How many replication origins are their per eukaryotic chromosomeMultiple
- 25What is the distance between origins of replication in eukaryotic chromosomes150k bp
- 26What direction does replication occurit is bi-directional
- 27What are intiator proteinsAid with the opening of double helices to form replication bubbles
- 28What is the approx. number of nucleotides in the human genome6 billion
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- User has deleted their subject information Flashcards on Th2L02 DNA replication, created by Deleted user on 26/08/2016.
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- Deleted user · Aug 2016
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- Aug 27, 2016
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- Created by Emma Allde · Aug 20, 2016
- Copied by Emma Allde · Aug 26, 2016
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