Principles 1.1 - Exam I Flashcards
Microorganisms of the human body include:
- bacteria
- viruses
-fungi - protozoa
- helminths
A collection of microbial organisms that are present within the human body:
microbiome
Components of the human body microbiome include:
- bacteria
- viruses
- fungi
- protozoa
Why are helminths not necessarily considered microbes?
due to their size
Makes up the vast majority of the human microbiome:
bacteria
List three examples of the various shapes of bacteria:
Cocci- round
Bacilli- rod
Spirilla- corkscrew
Eukaryotic microbes include:
protozoa & fungi
Prokaryotic microbes include:
bactreia
Describe the relationship of parasitic organisms:
not considered a benign relationship
Symbionts that harm or live at the expense of their host:
parasitic organisms
Organisms that live within or on us:
symbionts
Normal microbiota would be considered ____ organisms
commensal organisms
Microbes frequently found on or within the bodies of healthy persons:
normal microbiota
Growth or multiplication of parasite on or within the host:
infection
disease resulting from infection
infectious diseases
Overgrowth of Candida albicans due to changes in homeostasis would be an example of:
endogenous infection
any parasitic organisms that causes infection disease:
pathogen
causes disease by DIRECT interaction with the host:
primary pathogen (frank pathogen)
causes diseases ONLY under certain circumstances
opportunistic pathogen
Give an example of an opportunistic pathogen:
candida albicans
ability of a parasite to cause disease:
pathogenicity
Pathogenicity is often mediated by:
virulence factors
Any component of a pathogenic microbe that is required for or that potentiates its ability to cause disease:
virulence factor
Give two examples of virulence factors:
- a toxin that a pathogen produces
- tropism for certain tissue types
List the steps in an infectious disease:
- encounter
- entry
- spread
- multiplication
- damage
- outcome
What are three types of encounters that may lead to an infectious disease?
- exogenous
- endogenous
- congenital
When the pathogen is encountered from the outside environment:
Give example!
exogenous encounter; inhalation of someones sneeze
When the pathogen is encountered from the internal environment (within us):
Give example!
endogenous encounter; pneumococcal pneumonia
When the pathogen is encountered in utero or during birth:
Give example!
congenital encounter; HIV
What are the 3 endogenous sources that may lead to pneumococcal pneumonia?
- imparted natural protection/clearance system allowing for increased colonization of nasopharynx
- Colonized oropharynx and gastric fluid pool along tube in neonates
- Colonized tracheal secretions
What are the two mechanisms leading to pneumococcal pneumonia?
- aspiration of colonized fluids from endogenous sources into the lungs
- hematogenous source seeding the lungs (rare)
What are some manifestations that may occur in response to congenital infections? (3)
- growth retardation
- congenital malformation
- fetal loss
List the microbes that may cause congenital infections:
- rubella
- CMV
- HIV
- Toxoplasma
- T. Pallidum
- Parvovirus
- VZV
What are the two mechanisms of entry in contraction of an infectious disease:
- ingress
- penetration
Describe the entry mode “ingress”:
inhalation or ingestion
The mechanism of entry that occurs when microbes pass through epithelia DIRECTLY (via attachment and internalization)
penetration
Insect bites, cuts & wounds, organ transplants, and blood transfusions would all be considered ____ form of entry
penetration
Movement of pathogen within the human body:
spread
List the three components of spread of an infectious disease:
- lateral propagation vs. dissemination
- anatomical factors
- active participation by microbes
When the pathogen is spread far distant from the site of initial infection. Can give rise to systemic infection or complications :
dissemination
When spread of infection occurs from site of initial infection to adjacent tissue
lateral propagation
Separation but related to spread of infection; cell division/replication:
multiplication
What are the two components of multiplication?
- environmental factors
- subversion of host defences
When a virus encounters an increased body temperature this will turn on different genes within the microbe and allow for pathogenic factors to be expressed by the microbe which can further the infectious disease
This is an example of:
Environmental factors aiding in multiplication
Describe subversion of host defenses:
Pathogens don’t typically infect us without a defensive response from the immune system, and overtime pathogens have evolved and have many ways to conquer our host defenses
Fungal infection in rhino cerebral form, almost always with hyperglycemia and metabolic acidosis:
mucormycosis
A direct consequence of the actual pathogens replication:
direct damage
Damage that occurs as a result of the host defenses
immune response
What are two forms of damage due to an infectious disease:
- direct damage
- Immune response
List the outcomes of an infectious disease:
- microbe wins
- host wins
- coexistence
Microbes frequently found on or with the bodies of healthy persons:
normal microbiota
The normal microbiota is created by:
commensal organisms
colonization of bacterial rapidly after birth leads to:
our normal microbiota
The collection of all the microorganisms living in association with the human body:
the human microbiome
Components of the human microbiome include:
eukaryotes, archaea, bacteria & viruses
Describe the amount of bacteria in the human body relative to the human body cells:
bacteria are at an average of ten times more than the number of cells
Number of bacterial genes that are present in the human body due to bacteria:
1000 more genes than human genome
Percent of body mass comprised by bacteria:
1-3%
Bacteria in the microbiome are essential for producing:
- vitamins that we do not have the genes to make
- helpful anti-inflammatory compounds
Bacteria in the microbiome are essential for breaking down:
food to extract nutrients that we need to survive
Bacteria in the microbiome are essential for teaching:
our immune system how to recognize dangerous invaders
Bacteria in the microbiome are essential for occupying:
space to crowd out disease-causing microbes
Bacteria in the microbiome are essential for detoxification of:
carcinogens but sometimes are the source of carcinogen production
Changes in the composition of our microbiomes correlate with:
numerous disease states
What is a source of infection related to our microbiome:
changes in the composition of our microbiomes
manipulation of our microbiomes can be used to:
treat disease
List the locations in the body with the largest amounts of bacteria:
- skin (especially moist areas)
- respiratory tract (nose and oropharynx)
- digestive tract (mouth and large intestine)
- urinary tract (anterior parts of urethra)
- genital system (vagina)
List the locations of the body that are sterile:
- blood
- cerebrospinal fluid
- synovial fluid
- deep tissues
Whether a microbe gives rise to disease depends on: (2)
- inoculating number
- host organism
pathogenicity/virulence depend on the:
host & microbe
Give three examples where the normal flora are the source of infection:
- periodontitis
- pneumonia
- catheter-associated infections
Caused by overgrowth of particular bacteria in gingival crevices:
periodontitis
Occurs when defenses are lowered and microaspirations of pneumococci
pneumonia
Catheter-associated infections are commonly due to:
staphylococci
Oral flora include:
- bacteria (and archaea)
- fungi
- protozoa (eukaryotes)
- viruses
How many types of Bactria are usually present in the oral cavity?
~700 different species
Because the oral habitats each have different properties, this will promote the growth of:
different bacteria
List the different oral habitats:
- buccal mucosa
- dorsum of tongue
- tooth surfaces
- crevicular epithelium
- dental appliances
List the issues microbial cells may encounter:
- nutritional fluxes
- maintaining occupancy
- resistance to damage
Describe nutritional fluxes experienced by microbial cells:
nutrients are not constantly available & being metered out to microbes
Describe why it may be a challenge for microbial cells to maintain occupancy:
specifically a challenge along the alimentary canal due to constant flux of movement of fluids and foods that can create environments in which it is difficult to maintain occupancy
microbial cells in the human body must have the ability to resist:
damage brought on by immune response/host defenses
Factors modulating oral microbial growth include _____ that create areas that are ____.
anatomical features that are difficult to clean
List some anatomical features that create areas that are difficult to clean aiding in oral microbial growth:
- shape and topography of teeth (fissures)
- malalignment of teeth
- poor quality of restorations
- non-keratinized sulcular epithelium
List the two components of saliva:
inorganic ions & organic constituents
What makes up the organic constituents in saliva:
- proteins
- glycoproteins
Promotes adhesion of bacteria on tooth surfaces
saliva
organic components of saliva that form a coating on tooth surfaces:
salivary pellicle
Saliva is a source of ___ for oral microbial growth
food
Saliva promotes ____, facilitating their clearance from mouth
aggregation of bacteria
saliva inhibits growth of ___ by ____.
microbes; non-specific defense factors
Saliva allows for the maintenance of:
pH
fluid within the gingival crevice that has a different composition than saliva; a bit more like serum
gingival crevicular fluid
List the roles of gingival crevicular fluid:
- flushing microbes out of crevice
- source of nutrients for microbes
- maintains pH
- specific and non-specific defense factors
- phagocytosis
What is the main phagocyte in GCF
neutrophils
- competition for adhesion receptors
- toxin production
- metabolic end products
- coaggregation
These are all ___
microbial factors modulating oral microbial growth
List the microbial factors modulating oral microbial growth:
- competition for adhesion receptors
- toxin production
- metabolic end products
- coaggregation
The ability of a microbe to provide binding sites for other microbes:
coaggregation
List the factors modulating oral microbial growth:
- anatomical features creating hard to clean areas
- saliva
- gingival crevicular fluid
- microbial factors
- local pH
- redox potential
- antimicrobial therapy
- diet
- iatrogenic factors
varies with diet as a result of bacterial metabolism which in turn modulates oral microbial growth
local pH
A measure of the oxygen levels in locality that serves to modulate oral microbial growth:
redox potential
Dental scaling is an example of ____ which is a factor modulating oral microbial growth:
iatrogenic factors
3 domains of life include:
- bacteria
- archaea
- Eucarya
prokaryotic but distinct from true bacteria:
archaea
The word “extremophiles” can be used to refer to:
archaea
Life is presumed to have diverged from a common ancestor on Earth ~4 billion years ago and is based on the scientific deduction of the:
genetic structure of highly conserved genes within all cells
Life is presumed to have diverged from a common ancestor on Earth ~4 billion years ago and is based on the scientific deduction of the genetic structure of highly conserved genes within all cells, specifically:
ribosomes
A capsule of material surrounded by a plasma membrane that is reinforced by a cell wall:
prokaryotic cells
____ are an absolute requirement for all living organisms (prokaryotes & eukaryotes)
membranes
In prokaryotic cells, the plasma membrane encompasses the:
cytoplasm
IN addition to the plasma membrane, some prokaryotes also have:
internal membrane systems (though most bacteria do not have internal membrane systems)
The plasma membrane contains:
lipids and proteins
In the plasma membrane, more ___ are present than ____ in number but there is a 50/50 ratio of mass (due to the ___ being so much smaller)
lipids; proteins; lipids
The lipids of the plasma membrane usually form a:
bilayer
Describe the structure of the proteins in the plasma membrane:
usually embedded in PM or associated with the lipids
Give 4 descriptive words for the plasma membrane:
- highly organized
- asymmetric
- flexible
- dynamic
Most of the lipids making up the plasma membrane are:
amphipathic
The polar ends of the lipid membrane is considered ____.
charged
Describe the polar end of the lipids comprising the plasma membrane
charged, interacts with water, & hydrophillic
Describe the nonpolar end of the lipids comprising the plasma membrane:
insoluble in water, and hydrophobic
Long, non polar, hydrophobic ____ , also considered the R group, make up the non polar end of the lipids in the plasma membrane:
fatty acid chains
both polar and nonpolar components:
amphitpathic
Eukaryotes have ____ in addition to the amphipathic lipids making up the lipid bilayer:
cholesterol
bacterial version of cholesterol:
hopanoid
Bacteria have ____ in addition to the amphipathic lipids making up the lipid bilayer:
hopanoids
Another name for hopanoid:
bacteriohopanetetrol
Proteins that are loosely associated with the membrane and easily removed:
peripheral proteins
proteins embedded within the membrane and not easily removed:
integral proteins
sugar chains or saccharides added to lipids:
glycolipids
sugar chains or saccharides added to proteins:
glycoproteins
Separation of the cell from its environment is a function of:
plasma membrane
the plasma membrane can be described as a _____ barrier
selectively permeable
What does it mean when we say the plasma membrane is a “selectively permeable barrier”?
some molecules are allowed to pass into or out of the cell
____ aid in the movement of molecules (large & charged) through the plasma membrane
transport systems
____ & ____ can pass easily through the plasma membrane
water & other similar small molecules
The plasma membrane is a location of _____ processes
crucial metabolic processes
The crucial metabolic process that occur in the plasma membrane of bacteria include:
ETC
Functions in detection of and response to chemicals in surroundings with the aid of special receptor molecules:
plasma membrane
granules of organic or inorganic material that are stockpiled by cell for future use:
inclusion bodies
Some inclusion bodies are enclosed by:
Single-layered membrane (unusual though)
The (unusual) single-layered membrane that surrounds inclusion bodies varies in ____ (different from the PM) and some are made of ____ while others contain ____.
composition; proteins; lipids
_____, also known as nano machines, are complex structures consisting of protein and RNA
ribosomes
Component that is the basis for the tree of life:
RNA
Sites of protein synthesis:
Ribosomes
Prokaryotic ribosomes are _____ than eukaryotic ribosomes
smaller
Prokaryotic ribosomes can be labeled as ____, while eukaryotic ribosomes are labeled as ____.
70S; 80S
S when labeling ribosomes is the ____ unit which is a measure of ____.
Svedberg unit; sedimentation rate
Although ribosomes are ancient, highly-conserved nanomachines within cells, there are some fundamental differences between eukaryotic and prokaryotic ribosomes that manifest at a _____ level in terms of overall structure.
macro level
At a ____ level we will see differences in prokaryotic and eukaryotic ribosomes that can be exploited to create ____ that preferentially target prokaryotic ribosomes which is the basis for many therapies for microbial infections
micro level; antibiotics
What is the basis for many therapies for microbial infections?
targeting prokaryotic ribosomes
Bacteria do not usually have a membrane enclosed nucleus, but instead a region of compacted DNA called the:
nucleoid
The nucleiod region can be described as ____ shaped and the location of ___.
irregularly shaped; chromosome
There is usually only 1 ____ per cell in the nucleoid region of the cell.
chromosome
Is the nucleiod membrane bound?
NO
In actively growing cells, the nuceloid has projections; these probably contain:
DNA being actively transcribed
Why would there be multiple nucleioids within rapidly dividing cells?
DNA region replicates and divides before cell division so that each daughter cell contains its own set of DNA
Describe a prokaryotic chromosome:
closed circular, double stranded, looped and coiled extensively
What probably aids in folding of the prokaryotic chromosome?
nucleoid
Nucleoid proteins differ from:
histones
Unusual nucleoids:
- Some prokaryotes (refers to # of chromosomes)
- Some prokaryotes have chromosomes composed of:
- A few genera have ____ nucleoids
- greater than 1 chromosome
- linear double-stranded DNA
- membrane-delimited
____ are usually small, closed circular DNA molecules dependent of main chromosomal DNA
plasmids
Plasmids exist and replicate:
independently of chromosome
T/F: Plasmids are required fro growth and reproduction
False
T/F: Plasmids may carry genes that confer selective advantage (e.g., drug resistance)
True
Plasmids that are particularly notable are ones that confer drug resistance genes and this creates a population of bacteria:
resistant to therapy
The prokaryotic cell wall is a ____ structure that lies just _____ the plasma membrane
rigid; outside
- provides characteristic shape to cell
- protects the cell from osmotic lysis
- may contribute to pathogenicity
- may protect cell from toxic substances
cell wall
The plasma membrane is freely permeable to water and the interior of the cell is concentrated with solutes and so H20 will flow into the cells. The _____ functions to control the water flow to avoid the limit and prevent ____.
cell wall; osmotic lysis
The bacteria are divided into two major groups based on the cell walls response to:
gram stain procedure
Gram positive bacteria stain ____.
Gram negative bacteria stain ____.
positive= purple
negative= pink
The gram staining reaction is due to the:
cell wall structure
Single membrane bilayer underneath a thick peptidoglycan layer with small periplasmic space
gram-positive cell wall
Double membrane structure with each membrane being a bilayer (outer membrane and plasma membrane), with periplasmic space and a thin peptidoglycan layer:
gram-negative cell wall
The gap between the plasma membrane and cell wall (for gram-positive bacteria) or between the plasma membrane and outer membrane (for gram negative bacteria)
Periplasmic space
The periplasmic space is the gap between what structures in the gram positive cell?
between plasma membrane and cell wall
The periplasmic space is the gap between what structures in the gram negative cell?
between plasma membrane and outer membrane
substance that occupies the periplasmic space
periplasm
found in periplasm of gram NEGATIVE bacteria:
periplasmic enzymes
What are some functions of the periplasmic enzymes found in gram NEGATIVE bacteria?
- nutrient acquisition
- electron transport
- peptidoglycan synthesis
- modification of toxic compounds
Secreted by gram POSITIVE bacteria that perform many of the same functions that periplasmic enzymes do for gram negative bacteria:
exoenzymes
important component of BOTH gram-negative and gram-positive bacteria:
peptidoglycan
Peptidoglycan is a ____ formed from peptidoglycan subunits:
polysaccharide
The two alternating sugars that form the backbone of peptidoglycan include:
N-acteylglucosamine (NAG) & N-acetylmuramic acid (NAM)
Peptidoglycan contains some amino acids that:
are not observed in proteins (D-amino acids)
In gram negative Bactria, we often see a ___ side-chain linkage between ____ & ____ (linking adjacent subunits of peptidoglycan layer)
direct; D-alanine & DAP
Gram positive bacteria often contain a linkage of:
peptide interbridges (GLY-GLY-GLY-GLY)
The peptide interbridges that form in gram positive bacteria are linked between:
D-ala & L-lys
Composed primarily of peptidoglycan and contain large amounts of techoic acid:
gram-positive cell walls
In some cases, there is a lipid component at one end of the techoic acid which is referred to as:
lipotechoic acid
The lipotechoic acid will anchor ___ layer to the ___ .
peptidoglycan layer to the plasma membrane
polymers of glycerol or ribitol joined by phosphate groups
techoic acids
techoic acids are polymers of ___ or ____ joined by ____. They have both non polar and polar components to them!
glycerol or ribitol; phosphate groups.
Consist of a thin layer of peptidoglycan surrounded by an outer membrane
gram-negative cell walls
The outer membrane in gram-negative cells walls is composed of:
lipids, lipoproteins, and lipopolysaccharides (LPS)
What component is NOT found in gram-negative cell walls?
techoic acids
____ connect outer membrane to peptidoglycan
Braun’s lipoproteins
sites of DIRECT contact (possible true membrane fusions) between plasma membrane and outer membrane
adhesion sites
Substances may move directly through the cell through:
adhesion sites
What are located on the surface of gram-negative cells?
Lipopolysaccharides
What three parts make up lipopolysaccharides?
- lipid A
- core polysaccharide
- O side chain (O antigen)
A very long polysaccharide chain which tells us there is something on the exterior of the bacterium. Its visible to our immune system & we mount an immune response to it:
O-side chain (O antigen)
Portion of a LPSs that is visible to our immune system:
O antigen
portion of the LPS that is the hydrophobic tail that inserts into the plasma membrane:
lipid A
Portion of the LPS that contains heptose (Hep) and keto-doxyoctogenic acid (KDO):
core polysaccharide
Portion of the LPS that is a set of sugars that then is repeated creating a hair-like projection present all across the surface of the gram-negative cell
O side chain
Importance of LPS: (4)
- protection from host defenses (O-antigen)
- contributes to negative charge on cell surface (Core polysaccharide)
- helps stabilize outer membrane structure (lipid A)
- can act as an endotoxin (lipid A)
Portion of LPS that provides protection from host defenses:
O-antigen
Portion of LPS that contributes to negative care on cell surface:
core polysaccharide
Portion of LPS that helps stabilize outer membrane structure
Lipid A
Portion of LPS that can act as an endotoxin
Lipid A
The outer membrane of gram-negative bacteria is ____ than the plasma membrane
more permeable
The outer membrane of gram-negative bacteria is more permeable than the plasma membrane due to the presence of:
porin proteins and transporter proteins
form channels through the outer membrane of gram-negative bacteria through which small molecules (600-700 daltons) can pass
portin proteins
Outside of the cell wall, many bacteria have: (3)
capsules, slime layers, and s-layers
Layers of material lying outside the cell wall: (2)
capsules & slime layers
layer of material lying outside the cell wall, usually composed of polysaccharides and well organized, not easily removed from cell:
capsule
layer of material lying outside the cell all, usually diffuse, unorganized and easily removed:
slime layer
network of polysaccharides extending from the surface of the cell:
glycocalyx
A capsule or slime layer composed of polysaccharides can also be referred to as a:
glycocalyx
- provides protection from viral infection of predation by bacteria
- provides protection from chemicals in environment (like detergents)
capsular layers
Capsular layers aid in the ___ of gliding bacteria
motility
capsular layers provide protection against ____ stress
osmotic
Short, thin, hairlike, proteinaceous appendages, up to 1000/cell
fimbriae
Function of fimbriae is to:
mediate attachment to surfaces
Similar to fimbriae except longer, thicker, and less numbers (1-10/cell)
sex pili
Sex pili are required for:
mating
Some bacteria are motile due to:
flagella
One flagellum:
monotrichous
flagellum at the end of the cell:
polar flagellum
One flagellum at each end of the cell:
amphitrichous
Cluster of flagella at one or both ends of the cell:
lophotrichous
Flagella spread over the entire surface of the cell:
peritrichous
Flagella are ____ in structure
proteinaceous
Nanomachines involved in creating movement by transfusing energy in cells:
flagella
What are the 3 parts of a flagellum?
- filament
- basal body
- hook
Part of the flagellum that projects out from the cell surface:
filament
Part of the flagellum that is anchored within the plasma membrane or within the plasma membrane & outer membrane in gram negative cells:
basal body
Part of the flagellum that gives the bend to the flagellum that is important for the motion:
hook
Created when the bacteria encounter environmentally challenging conditions that make it difficult for the cell to continue growing:
bacterial endospore
when a bacteria form a bacterial endospore they are considered to be in a:
Dormant state
bacterial endospores are resistant to numbers environmental conditions such as:
- heat
- radiation
- chemicals
- desiccation
a specialized form of cell division that essentially creates a daughter cell within the “mother cell”
endospore
The endospore is located within the “mother cell” also known as:
sporangium
membrane delimited nuclei:
eukaryotic cell
Eukaryotic cells are generally ____ and ____ when compared to a prokaryotic cell
larger and more structurally complex
Irregular network of branching and fusing membranous tubules and flattened sacs (cisternae)
endoplasmic reticulum
The rough endoplasmic reticulum is responsible for the synthesis of:
secreted proteins
The rough ER is also referred to as:
the granular ER
The smooth ER is also referred to as:
the agranular ER
The smooth ER is devoid of:
ribosomes
Functions of the ER include:
- transports ___, ___ and other materials within the cell
- major site of _____ synthesis
- synthesis of ____
- proteins, lipids
- cell membrane
- lysosomes
membraneous organelle made of cisternae stacked on each other:
Golgi apparatus
stacks of cisternae:
dictyosomes
involved in modification, packaging, and secretion of membrane components (lipids) and proteins
Golgi apparatus
The __ face of the Golgi apparatus is associated with the ER (ER components delivered here)
cis
_____ move the ER components through the cisternae of the Golgi apparatus
transport vesicles
Components exit the Golgi apparatus through the ____.
trans face
lysosomes are produced from the:
ER
membrane-bound vesicles that contain hydrolytic enzymes needed for digestion of macromolecules
lysosomes
uptake of solutes or particles from outside to inside the cell, by enclosing them in vesicles or vacuoles pinched off from the plasma membrane
endocytosis
endocytosis bringing in particles or bacterial cells:
phagocytosis
endocytosis involved in bringing in solutes:
pinocytosis
site of TCA cycle activity:
mitochondria
Site where ATP is generated by electron transport and oxidative phosphorylation
mitochondria
What are the 3 components to the structure of mitochondria?
outer membrane, inner membrane, and matrix
- highly folded to form cristae
- location of enzymes and electron carriers for electron transport and oxidative phosphorylation
mitochondrial inner membrane
- contains ribosomes, mitochondrial DNA and large calcium phosphate granules
- contains enzymes of the tricarboxylic acid cycle and the b- oxidation pathway for fatty acids
mitochondrial matrix
the mitochondrial matrix contains: (5)
- ribosomes
- mitochondrial DNA
- large calcium phosphate granules
- enzymes for TCA cycle
- enzymes for B-oxidation of fatty acids
membrane bound structure that houses genetic material of cell:
nucleus
- dense fibrous material within the nucleus
- contains DNA
- condenses during cell division
chromatin
- double membrane structure that delimits the nucleus ( 2 sets of lipid bilayers that create a boundary)
nuclear envelope
The nuclear envelope is penetrated by:
nuclear pores
Allow for materials to be transported into or out of the nucleus
nuclear pores
The molecular unity of prokaryotes and eukaryotes includes:
- same basic chemical composition
- same genetic code
- same basic metabolic processes
