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88 Cards in this Set
- Front
- Back
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central dogma |
dna makes rna makes protein |
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bacteria usually have what type of chromosomes |
circular |
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in microbiology growth is what |
the increase in the number of cells |
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binary fission means what |
2 cells arise from 1 |
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when we have cell division each chromosome has to what |
partition into each of the 2 daughter cells |
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transcription is |
dna converted into mrna by rna polymerase |
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after transcription, mrna is translated into what |
an amino acid sequence by the ribosome |
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dna polymerase makes what |
dna |
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rna polymerase makes what |
mRNA |
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ribosomes do what |
translate mRNA into proteins |
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supercoiling can be what |
introduced or taken out of circular molecules |
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supercoiling makes a molecule what |
smaller |
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supercoiling allows bacterial cells to do what |
pack huge amounts of dna into a tiny cell |
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if we add turns we introduce what type of supercoil |
positive supercoiling |
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if we remove turns what type of supercoiling is this |
negative supercoiling |
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If you have a negatively supercoiled molecule if you introduce extra turns into this it will turn into what |
back into a circular molecule |
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Introducing or removing turns from a molecule can change what |
its shape |
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If we have a supercoiled molecule its more difficult for what |
for rna polymerase to access so is more difficult to transcribe as the 2 strands are difficult to seperate |
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Heavily supercoiled molecules means what |
gene expression tends to be lower |
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relaxed dna has what |
the number of turns in the helix predicted by the length of the molecule |
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If linearized the E. coli chromosome would be how long |
1mm in length |
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supercoiling is carried out by what enzymes |
topisomerases |
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what trait of dna affects gene expression |
superhelicity |
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if there are not many supercoils, gene expression will be what |
higher |
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a relaxed circle maximises what |
gene expression |
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dna gyrase is required for what |
dna replication |
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Negative supercoils introduced by |
topoisomerase, DNA gyrase (topoisomerase II) |
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Topoisomerase I removes what |
negative supercoils (it relaxes dna) |
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Topisomerase IV does what |
relaxes DNA and introduces positive supercoils |
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Through the activity of topoisomerases the chromosome can be what |
supercoiled and relaxed |
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the major groove is what |
where many transcription factors will bind |
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proteins act mainly with what on the dna helix |
major groove |
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new bases are added to what |
3 prime hydroxyl group |
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new bases are added to what |
3 prime hydroxyl group |
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dna polymerase always proceeds in what direction |
3 prime to 5 prime direction |
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nucleic acid synthesis always occurs in what direction |
5 prime to 3 prime direction |
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you always require what to initiate synthesis |
a primer |
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what does semiconservative mean |
new double helices consist of one new and one old strand |
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short rna primer is always required to what |
provide a 3 prime hydroxyl group to initiate dna synthesis |
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how is the leading strand replicated |
continuously |
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how is the leading strand replicated |
continuously |
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how is the lagging strand replicated |
discontinously |
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rna primer binds to which end |
3 prime end |
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dna polymerase follows what |
replication fork |
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why is the lagging strand difficult to replicate |
as it starts with the 5 prime end so we cant add on bases, we have discontinous replication |
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what does dna gyrase do at the replisome |
removes the buildup of supercoils ahead of the replication fork |
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what happens if you stop dna gyrase at the replisome |
the replication fork will stop due to the buildup of supercoils |
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what is the role of dna polymerase 1 in the sealing of the lagging strand |
it removes the exised primers |
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what is the role of dna polymerase 1 in the sealing of the lagging strand |
it removes the exised primers |
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what is the role of dna polymerase 3 in the sealing of the lagging strand |
fills in the gaps |
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what is the role of dna gyrase in the sealing of the lagging strand |
seals the gaps |
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why do we seal the lagging strand |
because we dont want unwinding |
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why are we not all affected by cancer due to dna mutations |
because we have dna repair systems |
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what is another job of dna polymerase 3 |
it has proofreading activity |
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what does dna polymerase 3 do if it finds a mismatched base |
removes it and synthesises a new strand |
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why is dna repair so important |
to ensure replication is done correctly |
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where does replication begin for circular dna |
at the origin of replication |
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what do we not have to worry about with circular chromosomes |
the ends |
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where will the 2 replications meet in circular chromosomes |
at the terminus, which allows the daughter chromosomes to appear |
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what happens after dna replication is complete in circular dna |
the 2 circular chromosomes are connected like links in a chain and need seperated |
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how are the 2 daughter circular chromosomes broken apart after replication is complete |
topisomerases break one of the strands which breaks the link in the chain and they are joined back together once seperated |
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what speed are nucleotides added at during circular dna replication |
1kbp per second |
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what speed are nucleotides added at during circular dna replication |
1kbp per second |
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how long does circular dna chromosome replication take |
40 minutes |
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how long does it take e. coli to double |
20 minutes |
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what is special about replication forks in the replication of circular dna |
it can have multiple replication forks |
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what does it mean to say that the daughter chromosomes are catenated after replication of circular dna |
they are linked like a chain |
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what happens to the origin during dna replication and cell division in e. coli |
the origin moves to mid cell |
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why is the origin attracted to mid cell during dna replication and cell division in e. coli |
its thought that it may be due to phospholipids in the membrane of the cell but we arent sure exactly why |
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why is the origin attracted to mid cell during dna replication and cell division in e. coli |
its thought that it may be due to phospholipids in the membrane of the cell but we arent sure exactly why |
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where do the daughter origins move to in dna replication and cell division in e. coli |
to the 1 quarter and 3 quarter points of the cell |
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what are the 1 quarter and 3 quarter points of the cell going to be in dna replication and cell division of e. coli |
they are going to be the mid cell of the 2 daughter cells |
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what does FtsZ do |
dictate the site of cell division |
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what happens to FtsZ at mid cell |
a ring of FtsZ at mid cell around the origin, this is what dictates where cell division occurs |
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what is the location of the mid cell and origin facilitated by |
min proteins |
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why does the ring of FtsZ only form at mid cell |
because of the activity of the min proteins |
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why does FtsZ form a circle bound to the membrane |
as more components of the divisome are added the ring contracts until the 2 daughter cells pinch off |
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what does FtsZ do |
initiates cell division and forms the contractile ring |
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what does FtsZ do |
initiates cell division and forms the contractile ring |
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what does FtsA do |
ATP hydrolysing protein, provides energy for divisome assembly |
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what does ZipA do |
anchors Z-ring to cell membrane |
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what does ZipA do |
anchors Z-ring to cell membrane |
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what does Ftsl do |
makes peptidoglycan, is penicillin binding protein |
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what does ZipA do |
anchors Z-ring to cell membrane |
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what does Ftsl do |
makes peptidoglycan, is penicillin binding protein |
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what does FtsK do |
DNA translocase, pumps daughter chromosomes into appropriate daughter cell |
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why would FtsK pump the chromosomes into both daughter cells |
when one daughter cell does not have a chromosome as it will die without one, it needs one to produce rna, protein etc |
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what does topisomerase IV do |
unlinks (decatanates) daughter chromosomes |
