Practice Exam 1 Flashcards
Clavulanic acid is?
compound added to antibiotics to inhibit β-lactamases produced by bacteria
Lederberg and Tatum preformed experiments that conclusively demonstrated for the first time that?
bacteria can exchange genetic info leading to new phenotypes
Bacteria having a single mutation resulting in loss of FLH-C function would:
be unable to express class 2 flagellular genes
Bacterial cell has acquired mutation in its gene for DNA gyrase and has become resistant to an antibiotic. What class of antibiotics would it be resistant to?
Fluoroquinalones
Why is E.coli O157;H7 such a dangerous problem compared to other E.coli strains?
It has a shiga toxin that results in severe disease
The phylogenic tree of life divides life into domains based on?
Genetic relatedness based on rRNA sequences
indetify the most accurate answer that describes features of the domain Archaea
Archaea are prokaryotic organisms with certain features in common with bacteria and eukaryota
Peptidoglycan is found in the cell wall of gram positive bacteria, identify features of peptidoglycan:
held together via tetra-peptide linkages forming polymers of n-acetyl glucosamine and n-acteyl muramic acids
A spontaneous mutation results in Listeria without LLO function, the result of this mutation is?
the trapping of a bacteria within an intracellular vacuole
Bacterial plasmids..?
- apart of bacterial genome
- are extrachromosomal molecules
Describe features of gram negative cell walls?
- composed of outer membranes with external polysaccharides
- composed of keto-dioxy kdo covalently linked to lipid A
- O-specific polysaccharides covalently linked to core polysaccharide
Bacterial ribosome are often considered excellent targets for antibiotic therapy because?
The 30 and 50S subunits of the bacterial ribosomes are different from eukaryotic ribosomes.
Bacterial endospores are formed in response to environmental stresses and result in differentiated cells. Describe endospores.
Resistant to high heat, desiccation (being dried), ultra violet light.
Bacterial transcription occurs in the cytoplasm. Describe bacterial gene transcription?
RNA polymerase binds to promoter regions on DNA to promote mRNA synthesis
Bacterial efflux pumps are best described as?
protein complexes used to pump out toxic compounds from the cell
Describe features of AB-toxins
The B units exhibit binding specificity to allow toxin activity in specific cell types
Describe Urea Cholera.
Expresses an AB toxin and a pilus that result in pathogenesis.
AUG codon on sequence location helps in?
promoting open complex formation for protein translation
bacterial capsules are best described as?
slimy protective coat on cell surface made of polysaccharides
What is false regarding bacteria sigma factors?
- act to promote RNA translation at sp. DNA promoter elements
- provide specificity to RNA polymerase by binding to DNA promoter elements
What is a likely outcome of random mutations combined with selective pressure on a bacterial species?
the bacteria that thrives will out-compete other bacteria due to the mutations
When material cannot be heat treated for sterilization, what can be used to achieve biological sterility?
Radiation
The U-tube experiment was pivotal in demonstrating what?
bacteria must make cell-cell contact to exchange plasmid DNA by conjugation
Pathogenicity islands are best described as?
clusters of genes that encode info for virulence proteins