Bacteria Infection Flashcards
What is the function of Type I topoisomerase?
Form and reseal single-stranded breaks in DNA to decrease positive supercoiling
What is the function of Type II topoisomerase?
Perform these nuclease and ligase operations on both strands of DNA. Both of them can remove excess DNA to permit segregation of the DNA to daughter cells.
What is the semiconservative model? Who proposed it?
Watson and Crick showed: the two strands of the separate, and each functions as a for synthesis of a new complementary strand.
Why is replication necessary?
So both new cells will have the correct DNA
When does replication occur?
During interphase (S phase)
Describe how replication works
Enzymes unzip DNA and complementary nucleotides join each original strand
How many subunits associate to form the holoenzyme in bacteria?
Five; 2α, 1β, 1β’ and 1σ
How does rifampin block elongation?
By complexing with the β subunit of RNA polymerase
Why is transcription necessary?
Transcription makes messenger RNA (mRNA) to carry the code for proteins.
Describe transcription
RNA polymerase binds to DNA, separates the strands, then uses one strand as a template to assemble mRNA.
Why is translation necessary?
Translation assures that the right amino acids are joined together by peptides to form the correct protein.
Describe translation
The cell uses information from mRNA to produce proteins.
What are the main differences between DNA and RNA?
DNA has deoxyribose, RNA has ribose; DNA has 2 strands, RNA has one strand; DNA has thymine, RNA has uracil.
Using the chart to identify the amino acids coded for by these codons: UGGCAGUGC
tryptophan-glutamine-cysteine
Streptomycin and gentamicin are part of what class of antibiotics?
aminoglycosides
