Term
| What is the DNA structure? |
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Definition
Polymer
Double stranded
complementary bases
anti-parallel |
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Term
| What kind of replication does DNA do? |
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Definition
| Semiconservative, each old strand serves as a basis for a new strand |
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Term
| How many circular chromosomes do most bacteria have? |
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Definition
| A single circular chromosomes |
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Term
| What is the origin or replication? |
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Definition
| Where DNA replication begins |
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Term
| The process of DNA replication in Bacteria |
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Definition
Starts at a single circular chromosome at a single origin of replication
progresses outward in both directions-bidirectionally
This forms a replication bubble with a replication fork the site of replication, moving outward in both directions-bidirectionally
Each fork replicates both strands
The replication moves around the circle each way, until the fork meet up completing replication |
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Term
| What proteins are at the at the replication fork? |
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Definition
Topoisomerase
Primase
Helicase
RNA Primer
Single-strand binding proteins |
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Term
| Describe the process that occurs at the replication fork. |
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Definition
- Helicase separates the strands
- Single-stand binding (SSB) proteins keep separated strands from re-annealing (going back together
- Topisomerase relaxes 'supercoiling' that builds up ahead of helicase
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Term
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Definition
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Term
| What are the proteins involved with DNA Replication at the Fork? |
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Definition
Helicase
Single Strand Binding protein
Topoisomerase |
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Term
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Definition
| enzymes that polymerize nucleotides |
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Term
| What are the building blocks of DNA and RNA? |
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Definition
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Term
| What do polymerases need in order to polymerize nucleotides? |
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Definition
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Term
| What direction does the polymerase build nucleic acid polymers? |
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Definition
| Always builds from 5' to 3' direction |
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Term
| How do polymerase know that the nucleotide fits? |
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Definition
| They don't, they sample nucleotide triphosphates (NTPs) until they find one that fits and hydrogen bonds correctly with template |
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Term
What forms a link to the phosphate closes ot the sugar of the new nucleotide?
X |
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Definition
| The 3 OH on the strand of the nucleotide that is being added |
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Term
| Describe the process that Primase lays down an RNA Primer |
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Definition
DNA polymerases can only add a new base onto an existing end –they need not only a template, but also part of a second strand, a primer, on which to add new bases
RNA polymerases can start making a new strand from scratch,
with just a template
Thus to make DNA, you have to make a
short RNA primer that DNA polymerase
can then use to make DNA
Primase is an RNA polymerase that lays
down this primer |
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Term
| What does the RNA primer? |
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Definition
| Primase, lays down a primer |
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Term
| What is DNA polymerase III? |
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Definition
DNA Pol III
Adds deoxunucleotides to elongate the promer, thereby replicating the DNA linking them with a phiodiester bond |
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Term
| What are the two stands that deal with DNA polymerase? |
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Definition
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Term
What direction are DNA strands made?
X |
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Definition
they are antiparallel. yet synthesis is always 5' to 3'
one strand of the new DNA is made in the same direction as the replication fork is moving but the other |
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Term
| Are leading and lagging strands the same throughout a DNA polymerase? |
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Definition
| no, the fork is dependent on which are the leading and lagging |
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Term
| What is the cleanup process of DNA Replication? |
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Definition
Okazaki fragments (individual fragments created on the leading strand) has an RNA primer at the start, and there are gaps between each
A different DNA polymerase (DNA pol I) replaces the RNA primers with DNA
Ligase glues the gaps together |
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Term
| What is the enzyme that glues DNA together? |
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Definition
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Term
| What does the helicase do? |
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Definition
separate strands
Unwinds parental double helix at replication forks |
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Term
| What does the single-strand binding protein (SSB) do? |
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Definition
Keeps separated strands from re-annealing (going back together)
Binds to and stabilizes single-stranded DNA until it is used as a template |
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Term
| What does Topoisomerase do? |
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Definition
Relaxes 'supercoiling' that builds up ahead of helicase
Relieves overwinding strain ahead of replication forks by breaking, swiveling and rejoining DNA strands |
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Term
| What strand is made in the same direction as the replication fork is moving? |
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Definition
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Term
| Which strand is continuous? |
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Definition
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Term
| What strand is made 'backward' compared to the direction of the replication fork movement? |
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Definition
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Term
| What strand is made in discontinuous stretches? |
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Definition
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Term
| Where does the lagging strand go after it is released? |
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Definition
| To a newly exposed template |
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Term
| What is replicated as a series of Okazaki fragments? |
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Definition
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Term
| What is an okazaki fragment? |
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Definition
| Short/New synthesized DNA fragments that are formed on the lagging template strand during DNA replication |
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Term
| Describe the cleanup process for DNA replication |
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Definition
Each Okazaki fragment (as well as the leading strand)
has an RNA primer at the start, and there are gaps
between each
A different DNA polymerase (DNA Pol I) replaces the RNA
primers with DNA
Ligase glues the gaps together |
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Term
| What does the Primase do? |
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Definition
| Synthesizes an RNA primer at 5' end of leading strand and at 5' end of each Okazaki fragment of lagging strand |
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Term
| What does DNA pol III do? |
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Definition
| Uses parental DNA as a template, synthesizes new DNA strand by adding nucleotides to an RNA primer or a pre-existing DNA strand |
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Term
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Definition
| Removes RNA nucleotides of primer from 5' end and replaces them with DNA nuclotides |
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Term
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Definition
| Joins Okazaki fragments of lagging strand; on leading strand, joins 3' end of DNA that replaces primer to rest of leading strand DNA |
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Term
| What moves as single Replication Fork Complex? |
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Definition
| Helicase, lagging and leading strand polymerases |
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Term
| What forms a loop to allow okazaki fragment synthesis? |
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Definition
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