Exam 1 Flashcards
(161 cards)
1
Q
Germ theory of disease
A
some diseases are caused by microorganisms that have gained access to the human body
2
Q
purpose of koch’s postulates
A
to identify germs with infectious diseases; they became standards for linking a specific organism to a specific disease
3
Q
Koch’s first postulate
A
the suspected pathogen must be present in all cases of the disease and absent from healthy animals
4
Q
Koch’s second postulate
A
the suspected pathogen must be grown in pure culture
5
Q
Koch’s third postulate
A
cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
6
Q
Koch’s fourth postulate
A
the suspected pathogen must be reisolated and shown to be the same as the original
7
Q
two themes of microbiology
A
- understanding the basic life processes
- applying that knowledge to the benefit of humans
8
Q
What is microbiology?
A
microbiology is the study of microscopic life forms, called microorganisms
9
Q
evolution
A
the process of change over time that results in new varieties and species of organisms
10
Q
phylogeny
A
evolutionary relationships between organisms
11
Q
Last universal common ancestor (LUCA)
A
common ancestral cell from which all cels descended
12
Q
what are viruses composed of and what do they require?
A
They have a DNA or RNA core surrounded by a protein coat and sometimes a lipid membrane. They require a host to make copies of itself.
13
Q
what are diversity and the abundances of microbes controlled by?
A
resources, example nutrients, and environmental conditions like temperature, pH, O2
14
Q
microbial communities
A
microorganisms exist in nature in populations of interacting assemblages
15
Q
nomenclature
A
gives scientific names to organisms
16
Q
cytoplasmic (cell) membrane
A
barrier that separates the inside of the cell from the outside environment
17
Q
cytoplasm
A
aqueous mixture of macromolecules, ions, and ribosome
18
Q
ribosomes
A
protein-synthesizing structures
19
Q
genome
A
an organism’s complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism.
20
Q
Differences between eukaryotes and prokaryotes
A
membranes- lipid contents and lipids in prokaryotes do not contain cholesterol unlike eukaryotes, and organelles exist in eukaryotes and. not prokaryotes. Also genomes; prokaryotes have circular chromosomes and eukaryotes do not.
21
Q
8 True or false? All cells, prokaryote or eukaryote metabolize, grow, and evolve
A
true
22
Q
true or false? some cells, prokaryote or eukaryote, are able to differentiate, communicate with other cells, exchange genetic information with other cells, and move
A
true
23
Q
enzymes
A
protein catalysts of then cell that accelerate chemical reactions
24
Q
DNA replication
A
DNA chromosome is replicated
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transcription
DNA gene is read to produce RNA
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Translation
RNA message is read to make protein
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What results in growth?
growth is the result of the activities of metabolism; cells use metabolic processes to gain mass, replicate their DNA, and divide
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resolution
the smallest distance by which two objects can be separated and still be distinguished
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light microscopy
useful for examining cells while they are alive
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phase contrast microscopy and differential interference contrast microscopy
exploits the phase of light passing through an object varying thickness and density to produce an image
31
dark field
illuminating rays are directed from the side, so only scattered light enters the microscope lens
32
true or false, staining almost always kills the cells
true
33
What are some uses for a fluorescent microscopy
view a specific cell in a mixture of different cells, and view specific cell components in a cell
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morphology
cell shape
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coccus (pl. cocci)
spherical or ovoid
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rod
cylindrical shape
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True or false, morphology typically does NOT predict physiology, ecology, phylogeny, etc.
true
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what is the advantage for a cell being small
support greater nutrient exchange per unit cell volume, and tend to grow faster than larger cells
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what is the cell wall composed of
peptidoglycan, polysaccharides chains wrapped in circles around cell, and sugar chains
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Gram positive
-Capsules
-S-Layer (made of protein)
-Thick cell wall
-Lipoteichoic acids
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Gram negative
-Capsule
-Outer Membrane
-Thin cell wall
-Periplasm
-Plasma membrane
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Cytoplasmic membrane
surrounds the cell and separates cytoplasm from the environment
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hopanoids
pentacyclic chemicals that act to stabilize the bacterial membrane
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What is the membrane function
-Permeability barrier
-Protein anchor
-Energy conservation
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Integral membrane proteins
firmly embedded in the membrane
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Peripheral membrane proteins
one portion anchored in the membrane
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Channel (proteins)
Transports solute across membrane. Passive. Often called porins
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Carrier (proteins)
Transports solute across membrane. Active or Passive
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Receptor (proteins)
Binds extracellular or periplasmic molecules, confirmation change relays information to cell
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Enzyme
Facilitates chemical reaction
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Nutrient Transport
-Carrier mediated transport systems
-Highly specific
-Three major classes of transport systems in prokaryotes
-All require energy in some form, usually proton motive force or ATP
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True or false: carrier transport is faster than simple diffusion
true
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Uniporters
transport in one direction across the membrane
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Symporters
function as co-transporters
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Antiporters
transport a molecule across the membrane while simultaneously transporting another molecule in the opposite direction
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Simple transport
driven by the energy in the proton motive force
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Group translocation
chemical modification of the transported substance driven by phosphoenolpyruvate
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ABC transporter
periplasmic binding proteins are involved and energy comes from ATP
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What two types of lipid is the outer membrane of gram negative bacteria made of?
Inner leaflet composed of phospholipid, outer leaflet composed of lipopolysaccharide (LPS)
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Fimbriae
Short, helical filamentous protein structure
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Capsules and slime layers function
-assist in attachment to surfaces
-protect against phagocytosis
-resist desiccation
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Pili
Thin filamentous protein structure
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Pili function
allow for bacterial attachment to surfaces, and sometimes allows movement via twitching motility, and often helping bacteria to evade components of the innate immune system.
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True or false? Not all bacteria have pili
True
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Monotrichuous
single polar flagellum
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Amphitricuous
a flagellum at each pole
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Lophoticuous
multiple flagella localized at the cell pole
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Peritrichous
multiple flagella localized at the cell pole
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Taxis
directed movement in response to chemical or physical gradients
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chemotaxis
response to chemicals, the best studied movement system
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phototaxis
response to light
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aerotaxis
response to oxygen
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osmotaxis
response to ionic strength
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hydrotaxis
response to \water
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Conjugation
DNA exchange between two bacteria
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Flagella
long, helical protein filaments attached to a complex integral membrane protein "machine"
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True or false: not all bacteria have flagella
True
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Counterclockwise rotation (CCW)
Push cell forward; with peritrichous lophotrichous the flagella bundle together; some monotrichous cant rotate CCW
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Clockwise rotation (CW)
Peritrichous or lophitrichous "tumble"= change of direction; bidirectional monotrichous change direction = backtrack; unidirectional monotrichous= move forward
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Taxis
directed movement in response to chemical or physical gradients
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chemotaxis
response to chemicals, the best studied movement system
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phototaxis
response to light
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aerotaxis
response to oxygen
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osmotaxis
response to ionic strength
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hydrotaxis
response to water
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DNA is condensed by
supercoiling
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endospore
dormant, non-reproductive structure, that allows bacterial survival in harsh environmental conditions
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Metabolism
all the biochemical reactions taking place in an organism
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Catabolism
energy-releasing processes
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Anabolism
energy-using processes
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chemorganotrophs
generate ATP using oxidation of organic compounds
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chemolithotrophs
generate ATP using oxidation of inorganic compounds
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phototrophs
ATP generated from harnessing light energy
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heterotrophs
utilize carbon from organic compounds
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autotrophs
utilize carbon from CO2
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Free energy (G)
energy released that is available to do work
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Exergonic
reactions with a negative delta G zero which release free energy
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Endergonic
Reactions with a positive delta G zero require energy
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Activation energy
energy required to bring all molecules in a chemical reaction into the reactive state
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Catalyst
a chemical that increases the rate of a reaction without undergoing a physical change
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Enzymes function to do what
they act as catalysts, lowering activation energy of a specific reaction. They catalyze all chemical reactions in cells.
104
true or false? Enzymes act through enzyme-substrate complexes
true
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cofactors
small non-protein molecules that participate in catalysis but are not substrates
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apoenzyme
if an enzyme requires a cofactor to catalyze a reaction and that cofactor is not bound to the enzyme
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holoenzyme
an enzyme bound to its cofactor that is active is referred to as a holoenzyme
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Feedback inhibition
hinders a metabolic pathway by having a product of the pathway inhibit an earlier reaction
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What does an inhibitor do ?
inhibits an enzyme in the pathway so no product is available to feed the next reaction
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Noncompetitive inhibition
changing the shape of an active site
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Competitive inhibition
blocking an active site
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True or false, feedback inhibition can also be competitive or non-competitive inhibitors
true
113
prosthetic groups
cofactors that are inorganic molecules
114
coenzymes
organic molecules which include the various NAD+, NADP+, FAD, coenzyme A
115
Essential nutrients
those that must be supplied from the environment
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Macronutrients
major elements in cell macromolecules, and ions necessary for protein function
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Micronutrients
trace elements necessary for enzyme function
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What does liquid media allow for?
Allows for easily scalable growth, easy to manipulate growth conditions, and allows for continuous culture
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What does solid media allow for?
Allows for differentiation by morphology and separation of microbes for further pure culture.
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Pure culture
culture containing only a single kind of microbe
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Colony morphology
the physical appearance of bacteria grown on a solid media
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Selective medium
contains ingredients to inhibit growth of certain species and allow the growth of others
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Differential medium
contains specific chemicals to indicate species that possess or lack a biochemical process
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Bacterial colony
a visible cluster of bacteria growing on the surface of or within a solid medium, presumably cultured from a single cell
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B period
Cell increases in mass and size
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C period
The chromosome replicates and the two strands are segregated (separated)
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D period
synthesis of a septum forms two identical cells
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MreB
major shape-determining factor in prokaryotes
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Autolysins
sever pre-existing peptidogylcan creating breaks in the sugar backbone and peptide crosslinks
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Transglycolases
enzymes that interact with bactoprenol
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Transpeptidases
enzyme that forms the peptide cross links between adjacent glycan chains
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Binary fission
cell division following enlargement of a cell to twice its minimum size and the completion of one chromosome replication event!
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Fts
essential for cell division in all prokaryotes, and interact to form the divisome
134
Ftz
forms ring around center of cell
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ZipA
anchor that connects FtsZ ring to cytoplasmic membrane
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FtsA
helps connect FtsZ ring to membrane and also recruits other divisome proteins
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Batch culture
a closed-system microbial culture of iced volume
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Lag phase
interval between inoculation of a culture and beginning of growth, No cell division occurs while bacteria adapt to their environment
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Logarithmic
when exponential growth of the population occurs. Cells are healthiest in this state. In cases of human disease symptoms usually develop during log phase.
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Stationary phase
population growth is limited by one of three factors: 1. exhaustion of available nutrients; 2. accumulation of inhibitory metabolites or end products; 3. exhaustion of space, in this case called a lack of biological space.
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Decline/Death phase
the accumulation of waste products and scarcity of resources causes the population to decline in number; Cells die, but this does not mean all of the cells in the culture lose the ability to divide
142
What does continuous culture allow?
continuous culture allows for a scientist to keep a culture in exponential phase for longer periods than a batch culture
143
what does optical density of a culture calculate?
the approximate number of bacteria in a sample
144
Optimal prokaryotic growth is dependent on several physical factor in addition to nutrient levels in the environment
temperature, oxygen concentration, pH, hydrostatic pressure, osmotic pressure
145
what temperature do psychrophiles grow?
below 15 degrees celsius and make up the largest portion of all prokaryotes on Earth
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what temperature do mesophiles live at?
live at the medium temperature range of 10 to 45 degrees celsius including pathogens in the human body
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What temperature do thermophiles live best at?
60 degrees celcius in compost heaps and hot springs
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Hyperthermophiles are?
archaea that grow optimally above 80 degrees celcius found in seafloor hot-water bents
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Homeostasis
the tendency of a biological system to maintain internal stability, owing to the coordinated response of its parts to any situation or stimulus that would tend to disturb its normal condition or function
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Obligate aerobes
require oxygen to grow
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Microaerophiles
grow in low oxygen environments generally rich in carbon dioxide
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anaerobes
Do not or cannot use oxygen during growth
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Aerotolerant anaerobes
insensitive to oxygen
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Obligate anaerobes
inhibited or killed by oxygen
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facultative anaerobes
grow both with oxygen and without oxygen
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Capnophilic bacteria (microaerophiles)
require an atmosphere low in oxygen and rich in carbon dioxide
157
Thioglycollate broth
can be used to test an organism's oxygen sensitivity
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Neutralophiles
grow at pH 5-8, and include most human pathogens
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Acidophiles
grow at pH 0-5
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Alkaliphiles
grow at pH 9-11
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Osmosis
the diffusion of fluid, through a partially permeable membrane, from an area of low solute concentration to an area of high solute concentration
