Micro Final Flashcards
Contamination with ________ is a concern because they are highly resistant to killing.
endospores
The ________ are the largest known group of archaea.
methanogens
Cyanobacteria carry out the reactions of nitrogen fixation in specialized cells called
heterocysts
Members of the genus ________ are Gram-positive bacteria that show a distinctive process for cell separation known as “snapping cell division”, form an arrangement known as “palisades”, and cause the disease diphtheria.
Corynebacterium
Which of the following diseases is NOT associated with bacteria that form endospores?
tuberculosis, anthrax, botulism, gangrene, tetnus
tuberculosis
Which bacterial genera produce(s) endospores?
Bacillus and Clostridium
Which of the following bacterial genera includes species that protect areas of the body such as the intestinal tract and the vagina from invasion by pathogens?
Lactobacillus
Members of which of the following genera are the most common sexually transmitted bacteria in the United States?
Chlamydia
A flexible, spiral, corkscrew-shaped bacterium is called a
spirochete
A Gram-positive rod-shaped ________ is a frequent contaminant of dairy products and meat and can cause fatal newborn meningitis.
Escherichia coli
A _______ is a slightly curved rod.
vibrio
What is a pleomorphic prokaryote?
a prokaryote whose cell morphology varies in shape and size
Which of the following is NOT a means of reproduction in prokaryotes?
binary fission, meiosis, snapping division, budding
meiosis
What is the difference between spores and endospores?
spores are reproductive structures and endospores are stable resting structures
________ form when planes of cell division are random.
staphylococci
Which of the following is NOT a taxonomic domain?
protista, archea, bacteria, eukarya
protista
Scientists classify prokaryotes based on similarities in _______.
DNA, RNA, protein sequences
all of the above
Which statement BEST describes the extent of our current knowledge of prokaryotes?
most prokaryotes have never been isolated or cultured
Why are rRNA gene sequences an excellent tool for classifying bacteria?
genes are present in all known bacteria, part of the gene sequence is highly conserved, and part of the gene sequence varies from species to species
Which statement MOST accurately describes the taxonomy of bacteria described in Bergey’s Manual?
bacteria are classified based on the consensus opinion of experts at a particular point in time
Which of the following is NOT a difference between bacteria and archaea?
all archaea are extremophiles
What is an extremophile?
a microbe that requires extreme conditions of temperature, pH, and/or salinity to survive
How would you classify a microbe that requires temperatures over 80° C for growth?
hyperthermophile
An organism that requires an environment containing greater than 9% NaCl would be considered a ________.
halophile
Methanogens are obligate anaerobes that _______
convert CO2, H2, and organic acids into CH4
Which answer best describes “deeply branching bacteria”?
Microbes that appear to be similar to the earliest bacteria
An autotrophic bacterium ________.
produces organic compounds from carbon dioxide
How are phototrophic bacteria classified?
based on their pigments and sources of electrons for photosynthesis
According to the endosymbiotic theory, which group of phototrophic bacteria is MOST likely to have given rise to chloroplasts present in plants?
cyanobacteria
What is nitrogen fixation?
the reduction of nitrogen gas to ammonia
If organism X has a G + C content of 60% and organism Y has a G + C content of 35%, which of the following is most likely?
they are not closely related
Which of the following is a unique characteristic of mycoplasmas?
they lack cell walls