Microbiology Test 1
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360 Terms
What is a microbe?
Prokaryotes, single and multicellular eukaryotes that do not form tissues, including viruses
What is the problem with the Six Kingdoms classification system?
You cannot trace common ancestors
What is the classification system Six Kingdoms based on?
based on physiology
What is Florence Nighting gale known for?
Medical statistics
What is the spontaneous generation theory?
theory that living creatures could appear without parents
What is Louis Pasture known for?
discovered microbial fermentation
What is the germ theory of disease?
many diseases are caused by microbes
What is Robert Koch known for?
scientific method of biology
What are Koch's Postulates?
Microbe is always present in diseased host
Microbe is grown in pure culture (no other microbes present)
If you put the microbe in a healthy host they get sick
Some microbe that is re-isolated from now-sick individual
What is immunization?
the stimulation of an immune response by deliberate inoculation with an attenuated pathogen
What is Ignaz Semmelweis known for?
Antiseptic agents (washing hands w/ chlorine)
What is Alexander Fleming known for?
penicillin
What is Sergei Winogradsky known for?
discovered lithhotrophs
What is Robert Hooke known for?
built compound microscope
What is resolution?
smallest distance where two objects can be separated and still distinguishable from each other
What is detection?
ability to determine the presence of an object
What is magnification?
increase in the size of an image
What is the formula for resolution?
Lambda/2Na
What does lambda and NA stand for?
Lambda= wavelength
NA= numerical aperture of objective
A smaller wavelength means what?
better resolution
How do you find total magnification?
eyepiece (ocular) x objective = total magnification
What does it mean to "Fixate" a slide?
cells stick to the slide
What does it mean to "stain" a slide?
cells are stained with a color, most stains have conjugated double bonds, aromatic rings, or positive charges
What is a simple stain? What's an example?
Simple stain adds a dark color to the cells, but not surrounding tissue? Ex. methylene blue
What is a differential stain? What's an example?
stains one kind of cell, but not another. ex. gram stain
What color are gram positive and gram negative bacteria?
Gram positive: purple, keep stain because of thicker cell wall
Gram negative: pink, don't retain the stain
What is used in an acid fast stain? What species is it used for?
carbolfuchsin is used to stain Mycobacterium species
What is used in an Spore stain? What species is it used for?
malachite green is used to detect spores of Bacillus and Clostridium
What is used in a Negative stain? What species is it used for?
colors background, makes capsules visible
What is the shape of Bacilli?
rods
What is the shape of Cocci?
spheres
What is the shape of spirilla?
corkscrew
What is the shape of Spirochetes?
corkscrew
What do you see in Dark-Field Microscopy?
Microbes that are halos of bright light against darkness.
What is dark-field microscopy used to see?
flagella
very thin bacteria
How does fluorescence microscopy work?
specimen absorbs light of a defined wavelength and then emits light of lower energy (longer wavelength), specimen fluoresces
What is the difference between excitation and emission wavelengths?
Specimen absorbes light of specific wavelength (excitation wavelength) and then emits light at a longer wavelength (emission wavelength)
What is a fluorophore?
a fluorescent chemical compound
How can living cell imaging be done? What can be observed?
can be done with bright-field or fluorescence
living cells in real time can be observed.
What are essential nutrients in microbial nutrition?
nutrients that are supplied from the environment
What are the major elements in cell macromolecules ?
(P, C, O, H, N, S)
What are the ions necessary for protein function and considered macronutrients?
Mg^2+, Ca^2+, Fe^2+, K^+
What are the trace elements necessary for enzyme function, and considered micronutrients?
Co, Cu, Mn, Zn
What are growth factors?
specific nutrients not required by all cells
How do phototrophs obtain energy?
from chemical reactions triggered by light
How do chemotrophs obtain energy?
oxidation-reduction reactions
How do Lithotrophs obtain energy?
use inorganic (rocks) molecules as a source of electrons
How do organotrophs obtain energy?
use organic molecules
How do autotrophs build biomass?
CO2 --> sugar
How do heterotrophs build biomass?
use preformed organic molecules
What is something that fungi are able to digest?
complex organic compounds, like lignin
What does the lifestyle of fungi usually entail?
predation, parasitism, or scavenging for the dead
What is algae categorized as? How do they produce biomass?
algae is a photoautotroph, and produce biomass through photosynthesis.
What does it mean to be mixotrophic? Whats an example of a mixotroph?
can photosynthesize with light and also eat other organisms
ex. Euglena
What are permeases?
substrate-specific carrier proteins
What is facilitated diffusion?
high to low concentration, no energy use
What are the two types of ionophores? What do they do?
carrier ionophores - bind to an ion and carry it through the membrane
channel-forming ionophores - insert into the membrane and form a channel
What is group translocation?
process that uses energy to chemically alter the substrate during its transport
What is a coupled transport system?
energy released by a driving ion moving down its gradient is used to move a solute up its gradient
What are the two types of coupled transport systems, and how do they work?
Symport - two molecules travel in the same direction
Antiport - the actively transported molecules moves in the opposite direction of the driving ion
What does a defined minimal medium contain?
only the compounds needed for an organism to grow
What is the only place that Rickettsia prowazekii can grow?
within the cytoplasm of eukaryotic cells
What are the two main types of culture media?
Liquid/Broth
Solid (usually gelled with agar)
What is a complex media?
nutrient rich, but don't know exact amounts of what's in it.
What is in a synthetic media?
precisely defined (we know exact amounts of what is in it)
What is in a enriched media?
Specific blood components are added to complex media
What is selective media used for?
growing one type of bacteria over another
What is differential media used for?
to exploit the differences between two species that grow equally well
What is the definition of a viable bacterium?
a bacterium that can replicate and form a colony on a solid medium
How can viable cells be counted?
Pour plate method
What are the two main techniques to isolate pure colonies?
Dilution streaking
Spread plate
How does dilution streaking work?
bacteria are dragged across the agar surface in a pattern. Colonies grow only on the surface.
How does spread plate method work?
small amount of diluted sample is placed on the surface of agar and spread.
How does the pour plate method work?
Diluted sample is mixed with melted agar and poured into a plate.
How do dilution streak, spread plate, and pour plate differ in colony growth and purpose?
Dilution streak: surface only, isolate colonies.
Spread plate: surface only, count colonies.
Pour plate: surface + inside, count colonies + isolate colonies.
How do most bacteria divide? How does it work?
by binary fission, one parent cell splits into two equal daughter cells
How does Hyphomicrobium divide?
asymmetrically
What happens in binary fission?
a single cell divides into two equal daughter cells
What happens in multiple fission?
a single cell divides into many daughter cells at once
If a cell divides by binary fission, what is the number of cells is proportional to?
2^n (n=number of generations)
What is generation time?
The time it takes for a population to double in size.
What is a batch culture used to model?
used to model the effects of a changing environment
How is a batch culture made?
a liquid medium within a closed system
What happens in a continuous culture?
all cells in a population achieve a steady state (lets us study in detail the bacteria's physiology)
What does a chemostat do?
ensures logarithmic growth by constantly adding and removing equal amounts of culture media
What are the "normal" growth conditions?
Sea Level
20-40 degrees Celsius
Neutral pH
0.9% salt + nutrients
What is an extremophile?
an organism that lives in an ecological niche outside of "normal" growth conditions
What determines the environmental habitat that a species can inhabit?
The tolerance of the organism's proteins and other macromolecular structures to the physical conditions within that niche.
What does a bacteria cell's temperature match?
matches its immediate environment
Microbes that grow at higher temperatures usually achieve…
higher rates of growth
What is the growth temperature for Psychrophiles?
0-20 degrees C
What is the growth temperature for Mesophiles?
15-45 degrees C
What is the growth temperature for Thermophiles?
40-80 degrees C
What is the growth temperature for Hyperthermophiles?
65-121 degrees C
Growth rate roughly doubles for every _ rise in temperature
10 degrees C
What happens when rapid temperature changes are experiences during growth?
bacteria have heat-shock response
What is heat-shock response
when temperature suddenly increases during growth, microbes produce chaperones and proteases to stabilize
What do chaperones and proteases do during heat-shock response?
chaperones: refold damaged proteins
proteases: degrade irreversibly damaged proteins
What is special about barotolerant organisms?
grow well over the range of 1-50MPa, but growth falls off after that
What is special about barophiles and piezophiles?
adapted to grow at very high pressures