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56 Cards in this Set
- Front
- Back
compare transcription and DNA replicaiton
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no primer needed for transcription
only small region of DNA is copied |
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where does transcription and translation occur in euk
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transcription in nucleus
translation in cytoplasm |
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is RNA or DNA pol used for transcription
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RNA pol
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describe RNA pol in bacteria (what does it look like)
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holoenzyme alpha beta beta w sigma
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is the -10 -35 in prok or euk promoter
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prok
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how many RNA pols in euk
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3
I II III |
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what does the promoter region look like in prok
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TATA box
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what is the difference between an enhancer and a promoter
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enhancers can be far away and are orientation independent
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what type of RNA is in the pslicosome
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snRNAs
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what did nirenberg and leder do
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broek the genetic code using tRNAs
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what three letter sequence is always present at the 3' end
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CCA
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what are the three main steps of translation
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initation
elongation termination |
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how does initiation in prok differ from euk
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shine delgarno in prok
cap A and poly A tail in euk |
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where did you leave off?
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chap 16
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define mutation
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a heritable change to genetic information that cannot return to original sequence
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t or false. a mutation MUST be passed from one generation to the next
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false mutations could be within one cell in the body
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what is the difference between error and mutation
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errors can be corrected
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an error becomes a mutation after ____ occurs
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replication
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what are three types of mutation
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base subs
insertion deletion |
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what are two types of base substitutions
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transitions purine to purine
transversions purine to pyr |
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what are three possible phenotypic effect of mutations
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missense
nonsense silent (codes for the same aa but there is a different nucleotide seq) |
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give two reasons that mutations may not be expressed in the phenotype
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silent mutations
not all DNA is coding |
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what are two categories of mutation
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spontaneous
induced |
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what are two types of spontaneous mutations
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depurination
deamination |
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why is UV light bad
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pyrimidine dimers T=T
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how do euk protect from UV damage? prok?
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euk use pol eta to add 2 A's across the dimer
prok use photolyase and SOS in which it makes mutation after mutation hoping that one will make it more fit to the environemtn |
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what are three DNA repair pathways
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mismatch repair
base excision repair nucleotide excision repair |
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describe mismatch repair
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directly after DNA replication
mut H mut S mut L mut H bind at GATC mut s binds to mismatches mut L like mut H and mut S mut H chews DNA pol refills and ligase seals nick |
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describe BER
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DNA glycosylase removes damaged pr base and creates AP site
AP endonuclease recognizes AP site and removes sugar and phosphate DNA pol fills in ligase seals nick |
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describe NER
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removes bulky lesions like pyr dimers
UVR A B C D |
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are prok polycistronic? euk?
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prok ARE
euk are not because translation occurs via a different mechansim |
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what does polycistronic mean
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one mRNA with multiple open reading frames
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if you have high glucose do you want the lac operon on or off
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off
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describe how the lac operon works
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if no lactose, repressor is bound no txn
if lactose is present, induce binds repressor. Repressor canntoo bind to the operator and transcription does occur |
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cis acting elements bind proteins that regulate ____
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txn
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trans acting elements are the proteins that bind the _____ regions
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regulator
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what is a constitutive mutant
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cannot turn off the operon so lacZYA are transcribed regardless of the presence of lactose
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what isa consitutive operator
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a mutated operator where the repressor cannot bind and therefore txn always occurs
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what happens if lacI-
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I makes the repressor, non functional represson, so txn always occurs
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describe camp CAP and glucose effect on the operator
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if no glucose, then CAP and cAMP bid and txn occurs
if glucose, CAP cannot bind, no txn |
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the function of aminoacyl tRNA synthetase is to
a transcribe tRNA b match tRNA anticodons and mRNA codons c attach aa to tRNA d form peptide bonds between aas |
c. to attach aa to the tRNA
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what term refers to a contiguous genetic coplex that is under coordinate control
a. lysogen b. prototroph c. operon d. allosteric e. attenuation |
c. operon
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the SD seq interacts with
a. the tRNA met b. the 15S rRNA c. the large subunit of the ribosome d. the first AUG of the open reading frame |
b. the 16S rRNA
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do introns refer to RNA or DNA processing
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RNA
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the relationship between a gene and a messenger RNA is that
a. genes are made from mRNAs b. mRNAs are made from genes c. mRNA s make proteins, which then code for genes d. all genes are made from mRNAs e. messenger RNA is directly responsible for making okazaki fragments |
b. mRNAs are made from genes
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in the absence of glucose, e coli can use other foods because falling levels of glucose cause an increase of
a cAMP b CAP c lactose d glu operons |
a CAMP
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t or f. the template strand of DNA for one gene may be the coding strand of DNA for anotehr
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true
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during trasnlation, the __ site of the ribosome holds the growing aa while the __ site holds the next aa to be added to the chain
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P for polypep
A for active ready to be added |
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which of the following is an example ofthe degeneracy of the genetic code
a. a given aa have more than one codon b. each codon specifies more than one aa c. the first two bases specify the amino acid d. the genetic code is not degenerate |
a. a given aa has more than one codon
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what are the three modifications that have to happen to pre mRNA to make mature mRNA
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5' 7MG cap
polyA tail splicing to remove introns |
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where woudl euk RNA pols be found
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in the nucleus where transcription occurs
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list five steps at whch gene control can take place in euk
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transcription
DNA packagin RNA processing post translational modificaiton nuclear transprot |
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when does BER occur
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during interphase
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review lac operon +/- diagrams
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see exam II
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describe the triplet binding assay
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experiment by nirenberg and leder to break the genetic code. synthetic mRNA to only code for one aa. labeled and complex got suck in the filter
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list two types of spontaneous DNA damage that we discussed in class
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tautomeric shifts
depurination |