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BIMM 120 CH 8
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bacterial RNA polymerase holoenzyme is composed of?
core polymerase
: required for elongation phase
sigma factor
: required for initiation
sigma factors help detect ____
promoters
where are the consensus sequences for sigma-70
-35 and -10
One way to measure level of gene expression?
reporter proteins
how do sigma factors recognize specific DNA?
form fits function
initiation (transcription)
RNA polymerase holoenzyme binds to the promoter
elongation (transcription)
RNA chain is extended
termination (transcription)
RNA pol detaches from the DNA and releases RNA transcript
two types of termination signals
rho-dependent
: relies on protein rho and strong pause after stop codon
rho-independent
: GC rich region of RNA that forms hairpin, 4-8 consecutive U residues
two fundamental criteria for antibiotics
kill or retard growth of pathogen
must not harm the host
Rifamycin B
selectively binds to bacterial RNA polymerase and inhibits transcription initiation
actinomycin D
nonselectively binds to DNA
anti-cancer activity
small RNA (sRNA)
regulates transcription or translation
tmRNA
frees ribosomes stuck on damaged mRNA
how is mRNA stability measured?
half-life
half-life of mRNA
1-3 minutes
how many possible codons?
64 (3 are stop codons)
T/F - Each tRNA must be charged with the proper amino acid after it encounters the ribosome.
True
False
False, before
how are tRNAs charged?
aminoacyl-tRNA synthetase
two subunits of ribosomes
30S and 50S to form 70S
what makes the peptide bonds that stitch amino acids
peptidyltransferase
Shine-Dalgarno sequence
RBS that allows for proper reading frame
initiation (translation)
brings two ribosomal subunits together, placing first amino acid in position
elongation (translation)
adds amino acids
termination (translation)
releases completed polypeptide and ribosomal subunits
two antibiotics that affect translation
streptomycin and tetracycline
what proteins help the folding of proteins?
chaperones
protein degradation in bacteria
ATP-dependent proteases
protein degradation in eukaryotes and archaea
proteasomes
how are proteins meant for cell membrane tagged? What are they bound by? What do they undergo?
N-terminal signal sequences
signal recognition particle (SRP)
cotranslational export
pathway for protein export to periplasm
SecA-dependent general secretion pathway
Type 1 protein secretion
cytoplasm directly to extracellular environment
efflux ABC transporter
open reading frames (ORF)
sequence of DNA that encodes a polypeptide
orthologs vs paralogs
same function in different organisms
duplicated gene in different species with slightly different function
Author
andrewlee22087
ID
317429
Card Set
BIMM 120 CH 8
Description
bacteriology
Updated
2016-03-17T22:02:24Z
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