Exam 1 Flashcards
Symbionts that harm or live at the expense of their host
parasitic organisms
Microbes frequently found on or within the bodies of healthy persons:
commensal organsims
Commensal organisms may also be referred to as:
normal microbiota
What makes up the vast majority of normal flora?
bacteria
Colonization of ___ occurs rapidly after birth
bacteria
Locations in which large amounts of bacteria reside:
- skin (esp. moist areas)
- respiratory tract (nose and oropharynx)
- digestive tract (mouth & large intestine)
- urinary tract (anterior parts of urethra)
- genital system (vagina)
locations in which small amounts of bacteria reside:
remainder of respiratory and digestive tracts
Locations in the body in which NO bacteria are present (sterile):
blood, CSF, synovial fluid, and deep tissue
Normal flora found all over:
resident organisms
Resides in an area for a limited time:
transient organisms
Growth or multiplication of parasite on or within host:
infection
Disease resulting from infection:
infectious disease
Any parasitic organisms that cause infectious disease:
Parasite
Causes disease by DIRECT interaction with host:
primary (frank) pathogen
Causes disease only under certain circumstances (such as after antibiotic tx)
opportunistic pathogen
ability of a parasite to cause disease:
pathogenicity
any component of a pathogenic micro that is required fro or that potentiates its ability to cause disease:
virulence factor
Pathogenicity and virulence depend on:
the host
What are the steps in an infectious disease:
- encounter
- entry
- spread
- multiplication
- damage
- outcome
What are three types of encounters with a pathogen?
- exogenous
- endogenous
- congenital
When a pathogen is externally derives (such as a sneeze)
exogenous encounter
When a pathogen is internally derived (such as a change in immunity/health; already inside)
endogenous enconter
When a pathogen is picked up during birth (such as HIV from mother to fetus)
congenital encounter
What are two forms of entry of a pathogen?
- ingress
- penetration
Entry of a pathogen via inhalation or ingestion:
ingress
Entry of microbes through epithelial directly (via attachment and internalization):
penetration
Insect bites, cuts and wounds, organ transplants, and blood transfusions are all examples of what type of pathogenic entry into the host?
penetration
What are three components to the spread of a pathogen:
- lateral propagation vs. dissemination
- anatomical factors
- active participation by microbes
Spread of a pathogen to neighboring tissues:
lateral propagation
Spread of a pathogen to distant sites:
dissemination
What are the two components to the multiplication of a pathogen when causing an infectious disease?
- environmental factors
- subversion of host defenses
Damage inflicted by an infectious disease can be cause by:
- direct damage
- immune response
What are the outcomes of an infectious disease?
- microbe wins
- host wins
- they learn to coexist
If an infection comes from our normal flora, the source of infection is considered:
endogenous
Overgrowth of particular bacteria in gingival crevices:
periodontitis
When defenses are lowered and micro aspirations of pneumococci occur:
pneumococcal pneumonia
Catheter-associated infections are typically a result of:
staphylococci
What do the following have in common:
- periodontitis
- pneumococcal pneumonia
- catheter-associated infections:
All have endogenous source of infection- normal flora actin up
What are the roles of normal flora?
- immune stimulation
- keeping out pathogens
- assist in nutrition
- source of carcinogens vs. detoxification of carcinogens
Normal oral flora include:
bacteria, fungi, protozoa, and viruses
How many different species are estimated to be present in the oral cavity?
over 500
What are the different oral habitats?
- buccal mucosa
- dorsum of tongue
- tooth surfaces
- crevicular epithelium
- dental appliances
Issues for microbial cells include:
- nutritional fluxes
- maintaining occupancy
- resistance to damage
List all of the factors modulating oral microbial growth:
- anatomical features that create areas that are difficult to clean
- saliva
- gingival crevicular fluid
- microbial factors
- local pH
- redox potential
- antimicrobial therapy
- diet
- iatrogenic factors
____ are an absolute require for all living organisms
membranes
describe the plasma membrane:
- highly organized
- asymmetric
- flexible
- dynamic
The lipid components of the plasma membrane form a:
lipid bilayer
The polar end of the lipids in the lipid bilayer are ____, while the non polar ends of the lipids in the lipid bilayer are ____.
polar –> hydrophilic
nonpolar–> hydrophobic
Proteins that are loosely associated with the plasma membrane that can easily be removed:
peripheral proteins
Proteins that are embedded within the membrane that are not easily removed:
integral proteins
bacteria version of cholesterol that provides rigidity:
bacteriohopanetetrol
Functions of the plasma membrane include:
- separation of cell from environment
- selectively permeable barrier
- location of crucial metabolic processes
- detection & response to chemicals via receptor molecules
granules of organic and inorganic materials that are stockpiled by the cell for future use:
inclusion bodies
some inclusion bodies are enclosed by a:
single layered membrane
The single layered membrane that encloses some inclusion bodies: (2)
- vary in composition
- some made of proteins, others of lipids
Complex structures consisting of protein and RNA:
ribosomes
Sites of protein synthesis:
ribosomes
Compare the size of eukaryotic and prokaryotic ribosomes:
prokaryotic ribosomes are smaller
Size of prokaryotic ribosome:
Size of eukaryotic ribosome:
70s; 80s
Irregularly shaped region in bacteria in which a chromosome resides:
nucleoid
Is the nucleoid membrane bound?
no
In cells, what do the nucleoid projections indicate?
cells are actively growing; DNA being actively transcribed
Describe a prokaryotic chromosome:
- closed, circular, double-stranded DNA molecule that is looped and coiled extensively
Proteins that help to fold prokaryotic chromosomes:
nucleoid proteins
Describe some unusual circumstances of nuceloids:
- more than one chromosome
- LINEAR double stranded DNA
- membrane-delimited nucleoids
Small, closed, circular DNA molecules that exist and replicate independently of the chromosome:
plasmids
Plasmids are NOT required for:
growth and reproduction
Plasmids may carry genes that confer ____ such as ____.
selective advantage; drug resistance
Rigid structure that lies outside the plasma membrane:
prokaryotic cell wall
List the functions of the prokaryotic cell wall:
- provides characteristic shape to cell
- protects the cell from osmotic lysis
- may contribute to pathogenicity
- may protect cell from toxic substances
Bacteria are divided into two major groups based on:
response to staining (rx due to cell wall structure)
Gram positive cells stain:
purple
Gram negative cells stain:
pink
In a gram positive cell, the cell wall is composed of:
primarily of peptidoglycan
Cells that contain large amounts of techoic acids:
gram positive cells
polymers of glycerol or ribitol joined by phosphate groups
techoic acid
Space between plasma membrane and cell wall:
periplasmic space
Gram positive bacteria secrete:
exoenzymes
In gram positive bacteria, the exoenzymes serve as the ____ do for gram negative bacteria
periplasmic enzymes
Cell wall that consists of a thin layer of peptidoglycan surrounded by an outer membrane:
gram negative bacteria
The outer membrane in gram negative bacteria is composed of:
lipids, lipoproteins, LPSs
NO techoic acid present:
gram negative bacteria
What type of bacteria are more permeable?
Gram-negative
space between plasma membrane and outer membrane in bacteria:
periplasmic space
In gram negative bacteria, what is contained within the periplasm?
periplasmic enzymes
What are roles of periplasmic enzymes?
- nutrient acquisition
- electron transport
- peptidoglycan synthesis
- modification of toxic compounds
Describe the structure of peptidoglycan:
- polysaccharide formed from two peptidoglycan subunits
- two alternating sugars form backbone
What two alternating sugars form the backbone in peptidoglycan?
N-acteylglucosamine (NAG); N-acetylmuramic acid (NAM)
Within the peptidoglycan structure, _____ have a direct link between peptide chains, while ____ contain a peptide inter bridge (Gly) between side chains
Gram-negative bacteria; Gram positive bacteria
This image is showing a ____ cell wall
gram-positive
what is under the thick peptidoglycan layer in a gram-positive cell wall?
single membrane bilayer
This image is showing a ___ cell wall
gram negative
In a gram-negative cells, there is a ____ structure with each being a bilayer.
double membrane structure
Connect outer membrane to peptidoglycan in gram-negative bacteria:
Braun’s lipoproteins
Sites of direct contact between plasma membrane and outer membrane in gram negative bacteria:
adhesion sites
Substances may move DIRECTLY into gram negative bacteria via:
adhesion sites
What are the three components of a lipopolysaccharide (LPS)?
- lipid A
- core polysaccharide
- o-side chain (O-antigen)
Component of the LPS that inserts into the outer membrane structure for stabilization & can also act as an endotoxin:
Lipid A
The lipid A component of the lPS inserts into:
the outer membrane
Component of the LPS that contributes to the negative charge on the cell surface:
Core polysaccharide
What does the negative charge contributed by the core polysaccharide portion of LPS function to do?
avoids/masks host defenses
What two components does the core polysaccharide portion of the LPS contain?
keto-deoxyoctoenic acid and heptose
Portion of the LPS that provides protection from host defenses:
O-side chain
What component of the LPS is visible to our immune system:
O-antigen
Which membrane in more permeable in a gram-negative cell?
outer membrane
Why is the outer membrane of a gram-negative cell more permeable than the plasma membrane?
due to presence of porin proteins and transporter proteins
Form channels in the outer membrane through which small molecules can pass:
porin proteins
Layer outside of the cell wall that is well-organized, not easily removed from the cell, and takes the shape of the underlying cell
capsule
Layer outside of the cell wall that is similar to the capsules except diffuse, unorganized, and easily removed
slime layer
Capsules and slime layers are both referred to as:
glycocalyx
network of polysaccharides extending from the cell surface:
glycocalyx
What are the functions of the glycocalyx? (4)
- protection from viral infection or predation by bacteria
- protection from chemicals in environment
- motility of gliding bacteria
- protection against osmotic stress
Short, thin, hairlike, proteinaceous appendages (1000/cell)
fimbriae
What is the function of fimbriae?
mediate attachment to cell surfaces
Similar to fimbriae except longer, thicker, and less numerous (1-10/cell)
sex pili
What are sex pili required for?
mating; transfer of genetic material
What is the function of flagella?
motility
List the arrangements of flagella:
- monotrichous
- polar flagellum
- amphiptrichous
- lophotrichous
- peritrichous
One flagellum:
monotrichous
Flagellum at end of cell:
polar flagellum
One flagellum at each end of cell:
amphitrichous
cluster of flagella at one or both ends of cell:
lophotrichous
flagellum spread over entire surface of cell
peritrichous
Describe the flagellum ultrastructure:
- filament
- basal body
- hook
Portion of flagellum that projects out of cell surface
filament
Portion of flagellum that is anchored within the plasma membrane or within both plasma & outer membrane
basal body
portion of the flagellum that is a protein components that gives a bend to the structure:
hook
dormant form created when a bacterium encounters environmentally challenging conditions that make it difficult for the cell to keep growing
endospore
The bacterial endospore is resistant to numerous harsh environmental conditions such as:
- heat
- radiation
- chemicals
- desiccation
Overview of eukaryotic cells include:
- membrane-delimited nuclei
- membrane-bound organelles that perform specific functions
- more structurally complex than prokaryotic cell
- generally larger than prokaryotic cell
Elements required in large amounts:
macroelements
List the macroelements required for microbial physiology that are cell components of carbs, lipids, proteins, and nucleic acids:
- carbon
- oxygen
- nitrogen
- hydrogen
- sulfur
- phosphorus
The macroelements required for microbial physiology make up components of:
- carbohydrates
- lipids
- proteins
- nucleic acids
List the macroelements required for microbial physiology that exist as cations and play many roles including cofactors of enzymes:
- potassium
- calcium
- magnesium
- iron
List the trace elements required for microbial physiology:
- manganese
- zinc
- cobalt
- molybdenum
- nickel
- copper
Trace elements are mainly needed as:
cofactors of enzymes
components required for ALL organism survival:
- source of energy
- source of reducing equivalents (electron donors)
- source of carbon
Organisms that utilize light as a source of energy:
phototrophs
Organisms that oxidize organic or inorganic compounds as a source of energy:
chemotrophs
Organisms need electron donors for:
- ETC (energy producton)
- Redox reactions (energy production)
- Biosynthesis (in autotrophs from CO2)
utilize INORGANIC molecules as a source of reducing agent:
lithotrophs
utilize ORGANIC molecules as a source of reducing agent:
organotrophs
Utilize CO2 as the main/only source of carbon:
autotrophs
Utilize reduced, preformed organic molecules (such as glucose) for source of carbon:
heterotrophs
due to the the source of carbon utilized, most pathogenic bacteria are considered:
heterotrophs
- light energy source
- Inorganic electron donor
- CO2 carbon source
photolithotrophic autotrophy
- light energy source
- organic electron donor
- organic carbon source
photoorganotrophic heterotrophy
- chemical energy source
- inorganic electron donor
- CO2 carbon source
chemolithotrophic autotrophy
- chemical energy source
- organic electron donor
- organic carbon source
chemoorganotrophic heterotrophy (all pathogens)
Other nutrient sources required for bacteria include:
- nitrogen source
- phosphate source
- sulfur source
- growth factors
List where bacteria may get their source of nitrogen from:
amino acids, ammonia or nitrate (NO3-)
A few may obtain nitrogen from N2 (atmospheric nitrogen)
List where bacteria may get their source of phosphate from:
inorganic phosphate (PO4^3-)
List where bacteria may get their source of sulfur from:
sulfate (SO4^2-), or reduced sulfur (cysteine)
List where bacteria may get their growth factors from:
amino acids, purines and pyrimidines, & vitamins (small organic molecules)
- perform aerobic respiration only
- final electron acceptor is oxygen (reduced to H20)
strict aerobes
- perform anaerobic respiration
- final electron acceptor is an inorganic molecule (such as nitrate of Fe3+)
strict anaerobe
- perform fermentation
- final electron acceptor is an organic molecule (such as pyruvate reduced to lactate or acetyl-coA reduced to ethanol)
strict anaerobe
- can perform respiration & fermentation
- most medically relevant bacteria
facultative anaerobe
Final electron acceptor of strict aerobes:
oxygen (reduced to H2O)
Final electron acceptor is an inorganic molecule
strict anaerobe that performs anaerobic respiration
Final electron acceptor is an organic molecule:
strict anaerobe perfomring fermentation
Give an example of a facultative anaerobe and explain:
E. coli- can survive on a Petri dish (aerobic), and can survive in the intestines (anaerobic)
The respiratory chain of E. coli occurs in ______ ; for us it occurs in the _____.
membrane of cell; mitochondria
Unique to the oral cavity and requires a certain amount of CO2 in addition to oxygen
Capnophillic
List the gram positive bacteria in the oral cavity:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
List the shapes of the following gram-positive oral bacteria:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
- cocci
- cocci
- rods
- rods
List the oxygen requirements for the following gram-positive oral bacteria:
- streptococcus
- peptostreptococcus
- actinomyces
- lactobacillus
- facultative anaerobes
- strict anaerobes
- strict/facultative anaerobes
- facultative anaerobes
List the gram-negative bacteria found in the oral cavity:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
List the shapes of the following gram-negative oral bacteria:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
- cocci
2-6. rods - spirals
List the oxygen requirements of the following gram-negative oral bacteria:
- veillonella
- aggrgatibacter
- capnocytophaga
- porphyromonas
- prevotella
- fusobacterium
- spirochetes
- strict anaerobes
- capnophillic
- capnophillic
4-7. strict anaerobes
- move from higher concentration to lower concentration
- NO ENERGY requirements
facilitated diffusion
What is facilitated diffusion uptake driven by?
intracellular use of the compound
Compare the rate of facilitated diffusion vs. passive diffusion:
facilitated diffusion is much faster
What happens to the rate of facilitated diffusion as the concentration gets smaller:
as concentration gets smaller, the rate gets smaller, however the rate is more magnified at smaller concentrations
Carrier proteins embedded in the plasma membrane:
permeases
An active transport mechanism in which transported substances are chemically altered during the process:
group translocation
Group translocation may also be called:
phosphorylation-linked transport or phosphotransferase system
An example of group translocation would be:
glucose –> glucose-6-phosphate
system that moves a phosphate group and covalently links it to a transporter molecule; very common within bacterial cells:
group translocation
Where does the phosphate bond come from in group translocation and what does this serve as:
phosphoenolpyruvate (PEP); energy source
Some ____ & ____ are transported via group translocation
sugars & cariogenic bacteria
Energy is used to drive accumulation of a substance, which remains unchanged by the transport process:
active transport
Form of active transport that uses proton motive force (gradient of protons) by coupling to an energetically unfavorable transport event (concentration of a substance against a gradient)
Ion-driven transport systems
Give an example of a molecule that would use ion-driven transport systems:
amino acids
Coupling energetically favorable + unfavorable processes:
symport
Form of active transport that use membrane proteins that form a channel and drive substances through the channel using the energy from ATP hydrolysis:
binding protein-dependent transport systems
Give an example of a molecule that would use binding protein-dependent transport systems:
sugars & aminoacids
In all active transport mechanisms the transport processes use carriers that:
can become saturated
ferric iron is very ____, so ____ is difficult.
insoluble; uptake
Because ferric iron is insoluble and difficult to uptake, microorganisms use ____ to aid in the uptake.
siderophores
Describe the process of ferric iron uptake in microorganisms:
siderophore complexes with ferric iron and the entire complex is then transported into the cell
E. coli can grown on greater than 30 different ___ compounds, using each to obtain ____ , ____ & ____.
Organic compounds; carbon, H+/electrons, and energy
Bacteria that can use several hundred compounds to obtain carbon, reducing agents, and energy:
pseudomonas
_______ organisms have complex needs and can only grow in association with the human body or in complex culture medium (example: blood agar)
nutritionally fastidious
Given and example of a nutritionally fastidious bacteria:
staphylococci and streptococci
Have to replicate within living cells, but unlike viruses, they can carry out metabolic processes
obligate intracellular parasites
Give an example of a bacteria that is an obligate intracellular parasite:
chlamydia
Microbial growth in the real world is considered:
suboptimal
Different organisms have ___ growth rates
variable
What is a factor that protects bacteria?
stress responses
bacteria can still cause damage to the host when not growing through
- toxin production
- immunogenic processes
Mechanisms of adaption of bacteria function to:
- maximize efficiency in using energy and resources
- respond to changes
What are the results of regulation by microorganisms:
- pathways can be switched on or off
- pathways can be turned up or down
How is control among microorganisms established:
- enzyme activity
- number of enzyme molecules
All enzymes have ____ for catalysis, but some enzymes have ____ for regulation.
active sites; allosteric sites
____ sites bind regulatory molecules
allosteric sites
Describe the binding of a regulatory molecule to an allosteric site:
- noncovalent
- reversible
- affect activity of enzyme
Positive effectors ____ activity; while negative effectors ____ activity of an enzyme.
increase; decrease
In allosteric regulation: the higher concentration of regulatory molecules=
more activity
In allosteric regulation, effectors act to:
- change affinity of enzyme for substrate
- change vmax (rate of reaction)
Results in premature termination of transcription of mRNA:
attentuation
In attenuation, the ___ becomes stalled in the ___ of the mRNA (upstream of the coding region on the enzyme)
ribosome; attenuator region
During attenuation, even though transcription is not complete, what can occur and why?
translation can begin because transcription and translation occur simultaneously in bacteria
During attenuation, ____ are important for mRNA folding.
secondary structures (hairpin)
An example of a secondary structure used for mRNA folding during attenuation:
hairpin
In attenuation, what happens when leucine is present?
When leucine is present, leucine-rich region allows ribosome to read and translate A and B regions, causing formation of a C-D hairpin strucutre
In attenuation when leucine is present and a C-D hairpin is formed, this causes:
the RNA polymerase to dissociate from the DNA, terminating transcription
In attenuation when leucine is present and a C-D hairpin is formed, this causes termination of transcription, ultimately:
preventing the cell from making the enzyme to create more leucine
In attenuation, what happens when leucine is absent?
When leucine is absent, a high demand for leucine tRNA causes the ribosome to stall, allowing for formation of B-C hairpin structure
In attenuation when leucine is absent and a B-C hairpin has formed this allows for:
transcription to occur