DNA and Disease- Eukaryotic Replication

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Why is eukaryotic so much more complex?
Due to bigger, linear genomes that are divided into multiple, densely packed chromosomes
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What three essential DNA sequences are needed?
1) replication origin 2)centromere 3) telomere
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what is a centromere?
a sequence that attaches DNA to mitotic spindle via a protein complex- kinetochore
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Why do eukaryotes require multiple sites of origin? (2 reasons)
Due to sheer quantity of DNA and the packaging of DNA into multiple chromosomes
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What does ARS stand for? what is it?
Autonomously replicating sequence. The sites of origin in yeast
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How many ARS are there in 12 chromosomes?
400
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How does the pre-RC form?
ORC binds to ARS in an ATP-dependenent manner, and serves as a landing pad for other proteins involved in replication: cdc6, cdt1p and mcm2-7.
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In what phase does it form?
g1
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How many subunits is ORC made up of?
6 or more
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What does: a) ORC b) MCM c) RPA stand for?
a) Origin recognition complex b) Mini-chromosome maintenance c) Replication Protein A
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What does d) PCNA e) RFC f) FEN1 stand for?
d) Proliferative Cell Nuclear Antigen e) Replication Factor C f) Flap Endonuclease
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Describe the PCNA protein
A homotrimeric torroidal protein
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What is the RFC also known as?
The clamp loader
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How is timing of DNA replicators firing coordinated?
By compaction of chromatin
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What is 'active' chromatin, and when does it replicate?
Loosely bound (euchromatin), replicates early in the S-phase
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What is 'inert' chromatin, and when does it replicate? Give example
Highly condensed (heterochromatin), replicates late e.g. X chromosome
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What are AT rich sequences associated with?
Late replication
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What is the role of replication licensing?
It maintains the correct gene copy number in daughter cells
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What does 'licensing' entail?
RLF putting replicators in an initiation competent state
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What do RLF and SPF stand for?
Replication Licensing Factor and S-phase Promoting Factor
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Where are they found?
RLF= cytoplasmic, SPF= nuclear
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What do they do?
RLF- licenses replicators (so they are in an invitation competent state) SPF= induces initiation and removes license
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Comment on the a) no. of subunits, b) proofreading capability, c) processivity d) role of 1) DNA pol alpha 2) DNA pol delta
1) a) 4 b) none c) low d) initiation of leading and lagging synthesis 2)a) 4-12 b) proofreading ability c) high processivity when associated with PCNA d) mainly leading strand synthesis
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What are the roles of a) B and E DNA polymerases b) gamma DNA polymerases
a) DNA repair b) replication of mitochondrial DNA
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Card 2

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What three essential DNA sequences are needed?

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1) replication origin 2)centromere 3) telomere

Card 3

Front

what is a centromere?

Back

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Card 4

Front

Why do eukaryotes require multiple sites of origin? (2 reasons)

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Preview of the front of card 4

Card 5

Front

What does ARS stand for? what is it?

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