Ch 8 Microbial Genetics Flashcards
DNA contains _____ which are the instructions for making _______ and functional ___’s.
genes; proteins; RNA
Protein is:
a functional polymer of amino acids
A gene is:
a locus (or region) of DNA that encodes a protein or functional RNA product
Where are genes located in bacteria?
On large circular chromosomes and sometimes also on plasmids
What are plasmids?
Small, extrachromosomal, circular, self-replicating pieces of dsDNA
Are plasmids double or single stranded DNA or RNA?
dsDNA
What shape are plasmids?
Usually circular
Plasmids contain an origin of ________ (ori), but need _____ ________ to _________.
replication; host proteins; replicate
What direction is DNA synthesized in?
5’ -> 3’
Leading strand
synthesized continuously
Lagging strand
synthesized discontinuously in Okazaki fragments
To connect the Okazaki fragments _________ removes _____ _______. Adjacent Okazaki fragments are joined by _____ _______.
DNA polymerase; RNA primers; DNA ligase
How does a phosphodiester bond form?
through dehydration synthesis
Is DNA polymerase III very accurate in dNTP selection?
Yes
Exonuclease proofreading
Pol III and Pol I correct mistakes
Transcription begins at the ________ sequence and stops at the ___________ sequence.
promoter; terminator
3 phases of transcription
initiation, elongation, termination
Transcription initiation
the rna polymerase binds to the promoter region and separates the double helix
Transcription elongation
RNA polymerase travels along the DNA template and synthesizes RNA
Transcription termination
At the end of the gene, RNA polymerase encounters termination signal in DNA. RNA polymerase detaches from DNA and releases the RNA transcript (mRNA).
Translation
the synthesis of a protein (amino acids) guided by the template mRNA (nucleotides)
Start Codon
AUG
Stop Codon
UGA, UAG, UAA
mRNA
encodes proteins
rRNA
forms ribosomes