Principles 1-1 Flashcards
what are parasitic organisms
symbionts that harm or live at the expense of their host
what are commensal organisms
normal microbiota- microbes frequently found on or within the bodies of healthy persons
what is infection
growth and multiplication of parasite on or within host
what is infectious disease
disease resulting from infection
what is a pathogen
- any parasitic organism that causes infectious disease
what is a primary pathogen and what is another name for it
causes disease by direct interaction with host
- frank
what is an opportunistic pathogen
causes disease only under certain circumstances
what is pathogenicity
ability of parasite to cause disease
what is virulence factor
any component of a pathogenic microbe that is required for or that potentiates its ability to cause disease
what are the steps in an infectious disease
-encounter
- entry
- spread
- multiplication
- damage
- outcome
what are the types of encounters in infectious disease
exogenous, endogenous, congenital
what are examples of endogenous sources of micro organisms
- impaired natural protection/clearance system allows increased colonization of nasopharynx
- colonized oropharynx and gastric fluid pool along tube in neonates
- colonized tracheal secretions
what is the mechanism for pneumonia
-aspiration of colonized fluids from any of the above sources into the lungs can result in pneumonia
- a hematogenous source seeding the lungs may rarely cause pneumonia
what are the manifestations of a congenital infection
-growth retardation
- congenital malformation
- fetal loss
what are the types of entry and define both
- ingress: inhalation, ingestion
- penetration: microbes pass through epithelia directly, insect bites, cuts and wounds, organ transplants, and blood transfusions
what are the types of ways an infectious disease can spread
lateral propogation vs dissemination
what is spread determined by
anatomical factors
what is multiplication determined by
environmental factors
what are the results of damage
-direct damage
- immune response
what are the different possible outcomes
microbe wins, host wins or they learn to coexist
where is normal microbiota found
microbes frequently found on or within the bodies of healthy persons- commensal organisms
when does colonization of normal microbiota begin
rapidly after birth
what organisms make up the human microbiome
eukaryotes, archaea, bacteria and viruses
bacteria in an average human body number _____ times more than human cells
ten
bacteria contain about ____ more genes than are present in the human genome
1000
how much do bacteria make up the human body
1-3% of our body mass
what are the functions of good bacteria in the human microbiome
- produce vitamins we cant make ourselves
- break down our food to extract nutrients
- teach our immune system how to recognize invaders
- produce helpful anti inflammatory compounds that fight off other disease causing microbes
- occupy space to crowd out disease causing microbes
- detoxification of carcinogens but sometimes are the source of carcinogen production
what are the locations in the body with the largest amount of bacteria
- skin
- respiratory tract: nose and oropharynx
- digestive tract: mouth and large intestine
- urinary tract: anterior parts of urethra
- genital system : vagina
what are the locations in the body with the smallest amount of bacteria
remainder of respiratory and digestive tracts
what body locations are sterile
- blood
-CSF - synovial fluid
- deep tissues
what do pathogenicity/virulence depend on
the host
what is periodontitis
overgrowth of particular bacteria in gingival crevices
what are examples where normal flora are source of infection
-periodontitis
- pneumonia
- catheter- associated infections
what happens in a pneumonia infection
defenses lowered and microaspirations of pneumococci
what organism causes catheter associated infections
staphylococci
what does oral flora include
- bacteria and archeae
- fungia
- protozoa - eukaryotes
- viruses
how many different species of bacteria are in the oral cavity
about 700
what are parts of the oral ecosystem
- buccal mucosa
- dorsum of tongue
- tooth surfaces
- crevicular epithelium
- dental appliances
what are issues for microbial cells
- nutritional fluxes
- maintaining occupancy
- resistance to damage
what are factors that modulate oral microbial growth
- anatomical features that create areas that are difficult to clean
- saliva
- GCF
- microbial factors
- local pH
- redox potential
- antimicrobial therapy
- diet
- iatrogenic factors
what are the anatomical features in teeth that modulate microbial growth
- shape and topography of teeth
- malalignment of teeth
- poor quality of restorations
- non keratinized sulcular epithelium
what makes up saliva that controls microbial growth
-inorganic ions
- organic constituents
- proteins
- glycoproteins
what does saliva do
- promotes adhesion of bacteria on tooth surfaces through organic components that form a coating on tooth surfaces called a salivary pellicle
- source of food
- promotes aggregation of bacteria, facilitating their clearance from mouth
- inhibits growth of micorbes by non specific defense factors
- maintains pH
what does GCF do
- flushing microbes out of crevice
- source of nutrients for microbes
- maintains pH
- specific and non specific defense facotrs
- phagocytosis
what is the main phagocyte in GCF
neutrophils
what do microbial factors do
- competition for adhesion receptors
- toxin production
- metabolic end products
- coaggregation
what does local pH vary based on
diet as a result of bacterial metabolism
what is redox potention
a measure of oxygen levels in locality
what is an example of an iatrogenic factor
dental scaling
what are the 3 domains of life
- bacteria
- archaea
- eucarya
what do prokaryotic cells contain
- flagella
- nucleoid
-ribosome - inclusion bodies
- plasma membrane
- cell wall
- capsule
describe the importance of cell membranes to prokaryotes
- required for all living organisms
- encompasses the cytoplasm
what does the plasma membrane contain
lipids form a bilayer and proteins are embedded in them
how would you describe the plasma membraen
- highly organized, asymmetric, flexible and dynamic
what is the function of the plasma membrane
- separation of cell from its environment
- selectively permeable barrier
- transport systems aid in movement of molecules
- location of crucial metabolic processes
- detection of and response to chemicals in surroundings with the aid of special receptor molecules in the membrane
what are inclusion bodies
granules of organic or inorganic material that are stockpiled by the cell for future use
what are inclusion bodies enclosed by
a single layered membrane that may be made of proteins or lipids
what makes up a ribosome
protein and RNA
what are the types of ribosomes
- prokaryotic ribosomes: 70S
- eukaryotic ribosomes: 80S
which type of ribosome is smaller
prokaryotic
what is in the nucleoid
the chromosome, usually 1 per cell
is the nucleoid membrane bound
no
what do the projections in nucleoid contain
DNA being actively transcribed
describe the prokaryotic chromosome
- a closed, circular, double stranded DNA molecule
- looped and coiled extensively
what do nucleoid proteins do
aid in folding of chromosome
what are some components of unusual nucleoids
-some can have more than one chromosome
- some have chromosomes composed on linear double stranded DNA
- a few genera have membrane delimited nuceloids
describe plasmids
- usually small closed circular DNA molecules
- exist and replicate independently of chromosome
- not required for growth and reproduction
- may carry genes that confer selective advantage
describe the prokaryotic cell wall
rigid structure that lies just outside the plasma membrane
what are the functions of the cell wall
-provides characteristic shape to cell
- protects the cell from osmotic lysis
- may also contribute to pathogenicity
- may also protect cell from toxic substances
what are the 2 groups of bacteria divided into
gram positive bacteria and gram negative
what color do gram positive bacteria stain
purple
what color do gram negative bacteria stain
pink
what is the staining reaction of bacteria due to
cell wall structure
what is the gram positive cell wall made of
peptidoglycan and plasma membrane
what is the gram negative cell wall made of
outer membrane, peptidoglycan and plasma membrane
what is periplasmic space
gap between plasma membrane and cell wall (gram positive bacteria) or between plasma membrane and outer membrane (gram negative bacteria)
what is periplasm
substance that occupies periplasmic space
where are periplasmic enzymes found
in periplasm of gram negative bacteria
what are the functions of periplasmic enzymes
-nutrient acquisition
- electron transport
- peptidoglycan synthesis
- modification of toxic compounds
what are exoenzymes secreted by and what do they do
- secreted by gram positive bacteria
- perform many of the same functions that periplasmic enzymes do for gram negative bacteria
what forms the backbone of the peptidoglycan structure
2 alternating sugars called N- acetylglucosamine and N-acetylemuramic acid
what is polysaccharide formed by
peptidoglycan subunits
what is the gram positive cell wall made of
-primarily peptidoglycan
- large amounts of teichoic acids
what are teichoic acids
polymers of glycerol or ribitol joined by phosphate groups
what is the gram negative cell wall made of
- a thin layer of peptidoglycan surrounded by an outer membrane
- outer membrane composed of lipids, lipoproteins, and lipopolysaccharides
- no teichoic acids
what do Braun’s lipoproteins connect
outer membrane to peptidoglycan
what are adhesion sites
- sites of direct contact between plasma membrane and outer membrane
- substances may move directly into cell through adhesion sites
what are the 3 parts of a lipopolysaccharide (LPS)
-lipid A
- core polysaccharide
- O side chain (O antigen)
what are the function of LPS
- protection fro host defenses (O antigen)
- contributes to negative charge on cell surface (core polysaccharide)
- helps stabilize outer membrane structure (lipid A)
- act as an endotoxin (lipid A)
why is the outer membrane more permeable than the plasma membrane
due to presence of porin proteins and transporter proteins
what passes through porin proteins
small molecules 600-700 daltons pass through these channels
what are the components external to cell wall
capsules, slime layers and S layers
describe capsules
- usually composed of polysaccharides
- well organized and not easily removed from cell
describe slime layers
similar to capsules except diffuse unorganized and easily removed
describe the glycocalyx
- network of polysaccharides extending from the surface of the cell
- a capsule or slime layer composed of polysaccharides can also be referred to as a glycocalyx
what are the functions of the components external to the cell wall
- protection from viral infection or predation by bacteria
- protection from chemicals in environment
- motility of gliding bacteria
- protection against osmotic stress
what are fimbriae and what do they do
-short, thin, hairlike proteinaceous appendages up to 1,000 per cell
-mediate attachment to surfaces
what are sex pili and what do they do
- similar to fimbriae except longer, thicker and less numerous about 1-10 per cell
- required for mating
what are the patterns of arrangement and what does each mean
- monotrichous: one flagellum
- polar flagellum: flagellum at end of cell
-amphitrichous: one flagellum at each end of cell - lophotrichouse: cluster of flagella at one or both ends
- peritrichous: spread over entire surface of cell
what are the 3 parts to the flagella
- filament
- basal body
- hook
describe the bacterial endospore
- formed by some bacteria
- dormant
- resistance to heat, radiation, chemicals and desiccation
what is the general overview of the eukaryotic cell
- membrane delimited nuclei
- membrane bound organelles
- more structurally complex than prokaryotic cell
- larger than prokaryotic cell
describe the endoplasmic reticulum
irregular network of branching and fusing membranous tubules and flattened sacs
describe rough ER and the other name for it
- granular
- ribosomes attached
- synthesis of secreted proteins by ER associated ribosomes
describe smooth ER and the other name for it
-agranular
- no ribosomes
- synthesis of lipids by ER associated enzymes
what are the functions of ER
-transports proteins, lipids and other materials within cell
- major site of cell membrane synthesis
- synthesis of lysosomes
describe the golgi apparatus and its function
- memrbanous organelle made of cisternae stacked on each other
- dicytosomes: stacks of cisternae
- involved in modification, packaging and secretion of materials
which direction do materials move in the golgi
cis or forming face -> to the trans or maturing face
describe lysosomes and what they contain
-membrane bound vesicles
- contain hydrolytic enzymes needed for digestion of macromolecuels
what is endocytosis
uptake of solutes or particples by enclosing them in vesicles or vacuoles pinched off from the plasma membrane
what is phagocytosis
endocytosis of particles or bacterial cells
what is pinocytosis
endocytosis of solutes
what happens in the mitochondria
-tricarboxylic acid cycle activity
- ATP is generated by electron transport and oxidative phsophorylation
describe the 3 main components of the mitochondrial structure
- outer membrane
- inner membrane
- matrix
describe the inner membrane of the mitochondria
- highly folded to form cristae
- location of enzymes and electron carriers for electron transport and oxidative phosphorylation
describe the matrix of the mitochondria
- contains ribosomes, mitochondrial DNA, and large calcium phosphate granules
- contains enzymes of the tricarboxylic acid cycle and the beta oxidation pathway for fatty acids
describe chromatin
- dense fibrous material within the nucleus
- contains DNA
- condenses to form chromosomes during cell division
describe the nuclear envelope
- double membrane structure that delimits nucleus
- has nuclear pores that allow materials to be transported into or out of nucleus
what are the similarities between prokaryotes and eukaryotes
-same basic chemical composition
- same genetic code
- same basic metabolic processes
what are the differences between prokaryotes and eukaryotes
-eukaryotes have membrane bound nucleus
- eukaryotes have DNA complexed with histones
- eukaryotes have more than one chromosome
-eukaryotes have introns in genes
-eukaryotes have nucleolus
-eukaryotes undergo mitosis and meiosis
-eukaryotes have mitochonria, chloroplasts, plasma membrane with sterols, ER, golgi, lysosomes, microtubules, and cytoskeleton
- eukaryotes have larger flagella
- eukaryotes have a simpler cell wall lacking peptidoglycan
- prokaryotes have cell wall complexed with peptidoglycan
- eukaryotes have 80S ribosome, prokaryotes have 70S
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