Ch. 1 (Microbial Life)
Please define what a microbe and state the five categories of microbes.
A microbe is an organism or virus that is too small to be seen with the unaided human eye.
Five categories: Viruses, Bacteria, Archaea, Fungi, and Protists.
Which among A-D is matched correctly?
A)Pseudomurien: comprises cell wall of Archaea
B)Mycoplasma: thick peptidoglycan layer
C)Mycolic acids: unusual cell wall components of Archaebacteria species
D)Isoprene/terpenoids: phospholipids of Mycobacteria species
E)None are matched correctly
A) Pseudomurien: comprises cell wall of Archaea
You inoculate 500 bacterial cells into a liquid growth medium; the particular bacterial species has a 2 hour doubling time. How many cells will you have in 10 hours? (formula: NT = N0 x 2n)
A)10,000
B)5,000
C)16,000
D)32,000
C)16,000
Which statement below is false?
A) Filtration is an enumeration method of determining cell numbers in a culture that includes counts of both live and dead cells.
B) The best method for determining viable cell numbers in a sample is to dilute the sample, plate samples, and count colonies on the plates.
C) Quantification of cell numbers of a culture via microscopy using a Petroff-Hauser counting chamber can include counts of counts of both live and dead cells.
D) Pure culture work to obtain isolated colonies is best done using solid media.
E) Bacteria exhibiting pleiomorphic morphology would not be uniform in shape and size.
A) Filtration is an enumeration method of determining cell numbers in a culture that includes counts of both live and dead cells.
FtsZ protein, MreB protein, and CreS (crescentin) protein are associated with
A) MreB proteins are found in rod-shaped cells, not cocci
B) FtsZ protein is found in either coccus or rod-shaped cells
C) CreS protein is found only in comma, or curved shaped cells
D) Those cells that have MreB protein might also have CreS protein.
E) all of the above are correct
E) all of the above are correct
Which of the following statement/statements among A-E regarding microbes is/are false?
A) Unculturable microbes have been revealed through streak plate isolation studies.
B) Archaea is a type of eukaryotic unicellular microorganism that can live in extreme conditions.
C) The evolution of cyanobacteria allowed for the later evolution of cells with an aerobic metabolism.
D) Certain prokaryotes are autotrophs that can obtain energy from inorganic sources like iron (Fe2+), ammonium ions (NH4+), and hydrogen (H2).
E) Though changes were made later, the Kingdom Protista was originally formed to contain all microorganisms.
F) two of the statements among A-E are false
F) two of the statements among A-E are false
Bacteria of the genus Mycoplasma are all characterized
A) by the complete lack of a cell wall
B) as all being Gram-negative
C) as all being Gram-positive
D) as having mycolic acids in their cell wall
A) by the complete lack of a cell wall
Which of the following is a macronutrient for bacterial growth?
A) carbon
B) nitrogen
C) sulfur
D) phosphorous
E) All the above are macronutrients
E) All the above are macronutrients
In terms of optimum growth temperatures, bacteria classified as human pathogens would correctly be considered
A)thermophiles
B)psychrophiles
C) mesophiles
D) thermotolerant
E) mesotolerant
C) mesophiles
Which scientist, or pair of scientists, is incorrectly matched with their particular contribution to microbiology?
A) Winogradski and Biejerink: soil microbiology and discovery of lithotrophy
B) Robert Hooke and Antonie van Leeuwenhoek: first microscopists
C) Ignaz Semmelweis and Joseph Lister: use of disinfectants and antiseptics
D) Louis Pasteur: germ theory of fermentation
E) All are matched correctly
E) All are matched correctly
Which of the following is not applicable to an attenuated virus or bacterium?
A. They are weakened forms of the pathogenic virus or bacterium.
B. They are forms that can be used as vaccines to protect against certain diseases.
C. They are types of antibiotics.
D. They are created by heating or chemically treating the virus or bacterium.
C. They are types of antibiotics.
Certain bacteria have atypical cell wall features; for example, many ___________ possess membrane lipids comprised of terpenoid compounds rather than fatty acids; ______________ have large waxy lipids on the exterior of their peptidoglycan layer; and _________________ species completely lack a cell wall altogether.
A) Archaea; Mycoplasma; Mycobacteria
B) Archaea; Mycobacteria; Mycoplasma
C) Mycobacteria; Archaea; Mycoplasma
D) Archaea; Staphylococcus; E. coli
B) Archaea; Mycobacteria; Mycoplasma
Which is false regarding a defined or minimal growth medium?
A)cells would have to synthesize a number of intracellular components in order to grow on this medium
B)one would be able to determine the exact chemical composition of the medium
C)cells would typically grow slower on minimal medium, compared to growth on a complex medium
D)none are false; A-C are all true
D) none are false; A-C are all true
You have discovered a chemical that possesses antimicrobial properties; further testing of the compound is performed by adding it to a growing bacterial culture. Analysis revealed that, after addition of the chemical, the total viable count of the culture neither increased nor decreased, rather it remained constant (i.e., leveled off). Based on this information, you correctly hypothesize the chemical is a
A) bacteriolytic agent
B) bacteriostatic agent
C) bacteriocidal agent
D) sterilizing agent
E) an antibiotic
B) bacteriostatic agent
Pasteur's work with the French wine industry directly proved all of the following, EXCEPT:
A) Yeast are responsible for the chemical processes that produce wine.
B) The formation of acetic acid during wine production was due to the presence of contaminating microbes.
C) The formation of alcohol by yeast during wine production required oxygen.
D) Microbes can cause disease.
E) two of the above
E) two of the above
Genes for the capsid proteins are found in the:
A) plasmid
B) bacterial chromosome
C) envelope
D) ribosome
E) viral genome
E) viral genome
________________is a technique used to identify un-culturable microorganisms from environmental samples.
A) The streak plate method
B) Metagenomics
C) Pure culture isolation
D) Enrichment culture
B) Metagenomics
Suppose Pasteur's swan-necked flasks containing boiled broth became cloudy 24 hours after boiling. Which choice could best explain the turbidity or cloudiness in the broth without supporting spontaneous generation?
A) Endospores in the broth survived boiling and grew after the broth cooled.
B) Contaminating organisms in the broth killed by boiling became alive again after the broth cooled.
C) Chemicals in the broth came together to form living organisms.
D) The broth allowed light to pass through it with less interference after boiling.
E) Solid material in the broth dissolved during boiling.
A) Endospores in the broth survived boiling and grew after the broth cooled.
All of the following are true regarding fimbriae, pili, and flagella, EXCEPT:
A) Fimbriae and pili are generally used for attachment.
B) Specialized pili are used for DNA transfer between bacterial cells.
C) Bacterial chemotaxis occurs by the changing frequency of runs to tumbles.
D) Flagellar motion in a bacterium occurs in a rotary fashion, unlike a eukaryotic flagellum.
E) The pili of some bacterial species can be used for either a gliding or twitching type of motility.
F) There are no exceptions; A -E are all true.
F) There are no exceptions; A -E are all true.