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57 Cards in this Set
- Front
- Back
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most common form of DNA |
right handed double helix/beta DNA
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give 2 properties of the oriC (euk) |
AT rich, bidirectional |
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fntn of polymerase 1 in proks |
removes RNA primers
has 5' to 3' exonuclease and polymerase activity has 3' to 5' proofreading (exo) |
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fntn of polymerase 3 in proks |
main replicative polymerase
highly processive has 5' to 3' polymerase activity 3' to 5' exonuclease activity (proofreading) |
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how many nucleotides are added per minute during replication |
30'000
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what does DNA ligase do? |
seals the nicks in the leading strand in replication |
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what does DNA ligase use to seal the nicks? |
phosphates (2?) from ATP |
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what happens at the oriC |
DNA protein binds at 9 base pair repeats
forming DNA protein complex strand separation starts at 13 base pair repeats DNA helicase joins protein complex to produce replication bubble |
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what do RNA primers do? |
initiate replication
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what do SSBs do? |
coats single stranded pre-replicative DNA to keep it extended (NO HAIRPINS HERE!)
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what mechanism solves positive supercoiling |
topoisomerases |
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what do toposisomerases do |
they nick the DNA to release tension
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(euks) unique bits of cs replication |
shorter RNA primers and okazaki fragments, DNA replication is only in S phase, multiple oriC, nucleosomes, telomeres, at least 15 polymerases
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order of phases (G, S, etc) |
G1 to S to G2 to M and repeat to G1
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what happens in phase G1? |
growth metabolism |
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what happens during S phase? |
DNA replication and synthesis |
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what happens during G2 phase |
interphase (prepping for mitosis)
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what happens during M phase |
mitosis and cytokinesis
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what kind of RNA stays in nucleolus |
structural RNA (and snoRNA)
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where does snRNA go? |
stays in nucleus |
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RNA synthesis is unique because... |
precursors are rNRPs, only one strand of DNA is used as a template and RNA doesn't need primers to be initiated |
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what is the sequence of the pribnow box? |
(-10) 5' TATAAT 3'
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where can you find RNA polymerase 1 |
nucleolus
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what does RNA polymerase 1 make |
all rRNAs except for 5S |
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what does RNA polymerase 2 make |
nuclear pre-mRNAs
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what does RNA polymerase 3 make |
5S rRNAs, tRNAs, other small nuclear RNAs
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what does RNA polymerase 4 make |
siRNAs
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what does RNA polymerase 5 make |
some siRNAs and noncoding transcripts of siRNA target genes
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(in euks) what is TFIID used for? |
binding to the TATA box |
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what linkage is present in a lariat formation |
(unique) between the 5' phosphate of G and the 2' OH of A |
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what is lariat formation vital to? |
splicing introns |
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how is the 7-methyl guanosine cap linked to pre-mRNA? |
by a unique 5' to 5' phospho link
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where is the poly A tail added to pre-mRNA |
3' end, after AAUAAA sequence
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about how many A residues is the poly A tail made of? |
20-200 of them
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what are spliceosomes made up of? |
snRNPs (small nuclear ribonucleoproteins)
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what are snRNPs made up of? |
5 different snRNA types with proteins |
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how are nucleotides joined to one another |
the (3?) OH group of the sugar joins to the phosphate group of another(below it) |
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what kind(s) of RNA control(s) gene expression |
miRNA (microRNA), siRNA(small inhibitory), RNAi (inhibitory) |
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what is a common feature of the RNAs that control gene expression |
short, single stranded |
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how do the RNAs that control gene expression actually go about doing this? |
they block expression of complementary mRNAs |
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in proks, what is special abount helicase? |
it's a part of the polymerase (unlike in DNA) |
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in the tetrameric core/holoenzyme.... what is the fntn of alpha? |
assembly of the tetrameric core |
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in the tetrameric core/holoenzyme.... what is the fntn of beta? |
ribonucleoide triphosphate binding site |
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in the tetrameric core/holoenzyme.... what is the fntn of beta prime? |
DNA template binding region |
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for a 60S ribosome subunit, what does the S stand for? |
svedberg units |
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where do RNA synthesis and ribosome assembly take place in euks? |
the nucleolus |
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the amino acid on tRNA is attatched to what on the tRNA molecule |
the 3' end of the RNA |
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Where is the shine dalgarno sequence usually found |
close to the initiation site |
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what's the purpose of the shine dalgarno sequence |
this is where ribosomes bind |
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describe translation initiation in euks |
amino group of methionine on the initiator tRNA (not formylated) initiation complex forms at the 5' end of the mRNA (MG cap) instead of shine dalgarno sequence translation then starts at the first start codon that is found |
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where is the stop codon recognized in a ribosome |
in the A site |
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how to release the polypeptide from the ribosome? |
stop codon is sensed and a water molecule is added to the carboxyl terminus of the nascent polypeptide, releasing it |
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suppressor mutations |
alter anticodons on tRNA |
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how much of the euk genome is made up by transposons |
40% |
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name the prok DNA repair mechanisms (5) |
light activated repair excision mismatch post replication recombination error prone repair (SOS response) |
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3 basic features of excision repair |
a DNA repair endonuclease (or containing complex) recognizes, binds to, excises the damaged base(s) a DNA polymerase fills in the gap (using comple. strand) DNA ligase seals breaks left by polymerase |
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post replication recombination repair |
involves pairing and strand exchanges between DNA duplexes. bypasses, doesn't fix |
