Unit 1 Review Flashcards
Which of the following statements is FALSE?
-Microbial cells can exist as single cells.
-Microbial cells carry out their life processes of
growth independently.
-Microbial cells include both bacteria and viruses.
-Microbial cells are surrounded by a cytoplasmic
membrane.
-microbial cells include both bacteria and viruses
In what/which domain(s) of life is/are
microorganisms represented?
Archaea, Bacteria, and Eukarya
The person who described the “wee
animalcules” was _______
Antoni van Leeuenhoek
Louis Pasteur developed the
vaccine(s) for:
anthrax, fowl cholera, and rabies
Transparent double-sided dishes used
for growing microbes are most
commonly called _________
Petri dishes.
What are the
accomplishments of Louis Pasteur?
-Determined that the alcohol-making process was
mediated by microbial fermentation and thus
refuted the theory of spontaneous generation
-Developed heat sterilization techniques that
involved the creation of a specialized swannecked flask
-Developed the first rabies vaccine and treated
thousands of individuals
What is a pure culture?
a population of identical cells
Robert Koch contributed to the field of microbiology by:
develop the tuberculin test, formulate four postulates for
definitively linking a specific microorganism to a specific
disease, and use agar as a solidifying agent in growth
media.
The structure that confers structural
strength on the cell is known as the __________
cell wall.
Cyanobacteria and purple sulfur
bacteria both obtain energy from light.
However, only the ________ are capable
of releasing ________.
cyanobacteria / oxygen
________ was the first to describe
microorganisms, while ________ was the first person
to see bacteria.
Robert Hooke / Antoni van Leeuwenhoek
Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as mitochondria.
nuclei and membrane-enclosed organelles
Electron microscopy has greater
________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons.
resolution
An organism of the genus
Staphylococcus is ________, while an organism of the genus Spirochaeta is ________.
spherical / coiled
The cytoplasmic membrane could best be described as:
a highly selective permeability barrier
The use of the Gram stain in microbiology is important because it differentiates:
Bacterial cells with different types of cell walls
Cells move polar molecules across the cell membrane against a concentration gradient using:
energy and transport proteins
Bacteria stain as gram-positive or gram-negative because of differences in the cell ____
wall
You are given an electron micrograph of a bacterial cell. In the micrograph, you can clearly see 3 thin layers of different densities surrounding the cell. Based on the micrograph, you can infer that this cell is _________ and would appear __________ after application of the Gram stain procedure.
-gram negative
-pink
A major function of prokaryotic gas vesicles is to :
confer buoyancy on cells by decreasing their density
What is the biological function of endospores?
They enable organisms to endure extremes of temperature, drying and nutrient depletion.
Although the inner leaflet of the gram-negative outer membrane is composed mainly of phospholipids, the outer leaflet of the outer membrane contains:
Lipopolysaccharides (LPS)
When does endospore formation commence?
When bacterial growth ceases due to limitation of an essential nutrient
You find endospores of a particular species. What is most likely true of this species?
It is a gram-positive bacterium
The time interval required for the formation of two cells from one is called ________
generation time
Turbidity measurements are commonly utilized for monitoring ___________.
planktonic cultures
When attempting to determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method should be avoided?
Pour-plate method
An agar plate for counting colonies and maximizing statistical validity should ideally contain ___________
25-250 colonies
What temperature is most commonly used in autoclaves to sterilize growth media and other devices prior to experimentation?
121 degrees C
Most mesophilic organisms can grow in a temperature range of _________
20-45 degrees C
A bacterium possessing ____________ will produce O2 bubbles when placed in the presence of hydrogen peroxide.
catalase
What form/s of oxygen is/are generally toxic to living organisms?
Superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
How are serial dilutions generally made?
- when the appropriate viable count is unknown.
- based on powers of 10, although other serial dilutions factors are possible.
- to reach a suitable dilution while minimizing error.
A medium containing known substances in precise amounts is known as a ____________ media.
defined
The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is __________.
antisepsis
A _______ agent is a chemical that inhibits bacteria from reproducing, but does NOT necessarily kill them.
bacteriostatic
All microorganisms require ______________________________.
phosphorus, nitrogen, and sulfur
