Midterm 1 Flashcards

Question

host range

Answer 1

refers to the animals a pathogen can infect and produce disease in some organisms can infect only one type of host to produce disease = narrow (salmonella enterica serovar Typhi) other can infect multiple different hosts = broad (salmonella enterica serovar Typhimurium)

Answer 2

a disease caused by a pathogen (bacterial, viral, parasitic) that can be transferred from one host to another

Answer 3

an objective marker of disease fever, fluid filled rash, etc.

Answer 4

subjective indicator of disease pain, fatigue, etc.

Answer 5

is a collection of signs and symptoms that occur together and collectively characterize a condition

Answer 6

many S+S of disease are caused by the host's response to the infection -> this is called immunopathology

Answer 7

after a disease resolves, the pathological consequences called sequelae may develop a secondary issue as a result from the initial disease

Answer 8

infection where symptoms take longer to develop than in an acute infection but arise quicker than for a chronic infection

Answer 9

type of infection that might occur after an acute episode, the organism is present but no symptoms are the disease can reappear after time

Answer 10

initial site of infection from which organisms can travel through the bloodstream to another area of the body

Answer 11

infection caused by organisms traveling from a focal infection, when affecting several organ systems, its called a systemic infection

Answer 12

site of infection resulting from dissemination

Answer 13

presence of bacteria in blood, usually transient (lasting a short time), little, or no replication

Answer 14

presence and replication of bacteria in the blood aka. blood infection

Answer 15

presences of viruses in the blood

Answer 16

presence of toxin in the blood

Answer 17

infection in a previously healthy individual

Answer 18

infection that follows a primary infection, damages tissue is more susceptible to infection by a different organism

Answer 19

infection caused by 2 or more pathogens

Answer 20

infection transmitted from a health care worker to patient

Answer 21

infection acquired during a hospital stay aka. hospital acquired infection

Answer 22

infection acquired in the community, not the hospital.

Answer 23

1. incubation phase 2. prodromal phase 3. illness phase 4. decline phase 5. convalescence phase 6. long term

Answer 24

the route of transmission from one person or animal to another

Answer 25

infectious agent is transferred from one person or animal to the next

Answer 26

infectious agent is transferred from parent to offspring

Answer 27

organisms spread directly from person to person -> intimate interaction

Answer 28

pathogens spread indirectly through an intermediary -> may be living or non living ex. flood water, objects, insects

Answer 29

any medium that can transport infectious agents such as food, water, air

Answer 30

inanimate objects

Answer 31

living carrier of an infectious organisms ticks, mosquitoes

Answer 32

pathogens are passed from a parent to its offspring through infected eggs happens in arthropod vectors (ticks, mosquitoes)

Answer 33

is a reservoir that harbours the potential disease agent but does not have the disease ex. Neisseria meningitidis has no animal reservoir and is maintained in the human population by asymptomatic hosts

Answer 34

disease is present in a specific geographic location, at a low rate, pathogen is usually harboured in an animal or human reservoir

Answer 35

number of disease cases exceeds the endemic level in a short amount of time

Answer 36

worldwide epidemic influenza, Hiv, covid

Answer 37

infections of animals that can be transmitted to humans pathogens may or may not cause the animal reservoir to have a disease my be direct or indirect transmission

Answer 38

zoonotic disease pathogen does not cause disease in the animal host but does cause disease when bacteria "spills over" to humans

Answer 39

zoonotic disease virus does cause disease in the animal host and humans

Answer 40

2 different strains of influenza can infect the same animal (pigs) at the same time -> the strains exchange chunks of each others genomes -> creates a new virus, more infectious and deadly typically this is called antigenic shift

Answer 41

random mutations to the antigen on the pathogens body

Answer 42

genetic reassortment between strains of a virus broad host range may lead to antigenic shift

Answer 43

range of tissues and cells that a pathogen can infect

Answer 44

set of 4 criteria used to determine if a microorganism causes disease if they are +, the organisms is infectious - the organism must be present in every case of disease, but not in healthy subjects - the organism must be isolated from a diseased organism and grown in pure culture - when introduced to a healthy organism, it must cause disease - the organism must be re-isolated from the inoculated organism and identified as the original organism

Answer 45

lungs = mucociliary escalator, moves pathogens out intestine = peristaltic action, constant flow bladder = detrusor contraction, propels urine with tremendous force

Answer 46

is entry into the host, before adhesion

Answer 47

pili adhesins = hairlike appendages, they have tips with receptors for host cell surface non-pili adhesins will stick to the host cell tissues which normally promotes interaction between host cell and the pathogen typically both types will work together to secure a pathogen to a host cell

Answer 48

pili are made up of identical pilin protein subunits and the tip of the pilus contains an adhesion protein that binds to host cell receptors

Answer 49

1. colonization -> e.coli (UPEC) colonizes the vaginal and periurethral areas 2. migration to bladder -> uropathogens migrate from the periurethral area to the bladder 3. UPEC adherence and internalization -> UPEC type 1 pili (FimH protein at the tip) bind to uroplakins/mannosylated glycoproteins on the superficial bladder umbrella cells (this is called internalization) 4. Formation of intracellular bacterial communities (IBCs) -> inside the cells, UPEC multiply to form IBCs (little colonies) 5. Efflux and reinvasion -> UPEC efflux from IBCs to reinvade neighbouring cells (more e.coli leave the little colonies to get other cells)

Answer 50

are cell wall proteins that bind to host proteins like integrin or fibronectin causing a more intimate attachment examples of nonpilus adhesins: - bordetella pertacrin binds to host integrin - streptococcus protein F binds to host fibronectin - streptococcus protein M binds to host fibronectin and the complement regulatory factor H

Answer 51

type IV pili + neisserial opa nonpilis membrane proteins = more intimate attachments

Answer 52

used in extracellular immune avoidance coat bacterial cell wall to prevent phagocytes from attaching -> eventually defense mechanisms produce opsonizing antibodies against the capsule itself and are able to bind to it to allow for phagocytosis

Answer 53

used in extracellular immune avoidance proteins such as protein A can bind to the Fc region of an antibody (the straight part of the Y), which hides (sequesters) the bacteria from phagocytes

Answer 54

some pathogens can alter there antigenic structure to temporally become invisible to the immune system ex. salmonella expressing flagellin A can change to Flagellin B

Answer 55

extracellular immune avoidance quorum sensing will precent pathogens from synthesizing virulence proteins too early during infection the concentration of a serrated chemical autoinducer will increase as the # of bacteria increases, once the level of the autoinducer reaches a certain point the pathogen will detect the autoinducer and turn on the virulence gene expression

Answer 56

avoid innate and humeral immune mechanisms by living inside host cells -> go undetected

Answer 57

can invade host cells but can also survive outside the host cell ex. salmonella, shigella, listeria

Answer 58

invade and reproduce inside a host cell only ex. rickettsia, coxiella, bartonella

Answer 59

intracellular pathogens have 3 options to avoid being killed by a phagolysosome Fate 1 = survive in a phagolysosome Fate 2 = prevent phagosome-lysosome fusion Fate 3 = escape the phagosome

Answer 60

the organism allows phagosome-lysosome fusion and are adapted to live in the harsh environment coxiella burnetii is a bacteria that grows well in acidic phagolysosome environment -> are able to replicate, results in inclusion bodies

Answer 61

ex. salmonella, mycobacterium, legionella, chlamydia pathogens avoid the hazard of lysosomal enzymes by preventing the lysosome from fusing with the phagosome (a) Pathogens like Salmonella can remain inside the phagosome and prevent fusion with lysosome, (b) or gets expelled into extracellular space where (c ) bacterium can be engulfed by a macrophage and survive within the phagosome

Answer 62

ex. shigella, listeria break out of the phagosome before it fuses with a lysosome, they then move throughout the cytoplasm into adjacent cells by forming actin tails

Answer 63

1. plasma membrane disruption -> form pores in host cell membranes 2. cytoskeleton alteration -> can cause host cell actin (cytoskeleton) to polymerize or depolymerize, forcing the host cell to wrap around them and bring them into the cell 3.protein synthesis disruption -> target eukaryotic ribosomes and prevent protein synthesis 4. cell cycle disruption-> stop or stimulate host cell division 5. signal transaction disruption -> increases or decreases synthesis of critical signalling molecules 6. cell-cell adhesion disruption -> cleave proteins that bind host cells together 7. redirection of vesicle traffic -> fuse many intracellular vesicles together 8. blockage of exocytosis -> interrupt the movement of host cytoplasmic vesicles to the membrane 9. excessive activation of the immune response (super antigens) -> activate the immune response without being processed by antigen-presenting cells and trigger fever

Answer 64

production of the diphtheria toxin is activated under low iron conditions, which offers the organism a way to rob the host's iron stores by killing the cell is also an ADP-ribosyltransferase and AB toxin interrupts the protein synthesis

Answer 65

it is part of the outer membrane of the gram-negative cell wall that includes lipopolysaccharide can cause ____ when released: - fever - activation/depletion of clotting factors (petechiae) - activation of complement - vasodilation -shock -> death

Answer 66

cells without a true nucleus (no nuclear membrane) bacteria and archaea

Answer 67

cells with a true nucleus and other organelles animals, plants, fungi, protists

Answer 68

small in size DNA organized in the nucleoid throughout the cytoplasm small genome circular chromosome (usually), although many have multiple circular and linear chromosomes cell wall composed of peptidoglycan

Answer 69

wide range of cell size, from very small to very large DNA contained in nucleus, enclosed by nuclear membrane wide range of genome size, including very large linear chromosomes (in nucleus), mitochondria have one circular chromosome cell walls of plants and fungi composed of various carbohydrates (cellulose and chitin), but never peptidoglycan

Answer 70

cytoplasm of the cell is a gel-like network of proteins and other macromolecules -> contained by a cell membrane outside of the membrane is the cell wall, which is made of peptidoglycan outside the cell wall, gram-negative bacteria have an outer-membrane the cell membrane, cell wall, and outer membrane (for gram negative species) constitute the cell envelope the chromosome is organized within the cytoplasm as a system of looped coils called the nucleoid

Answer 71

30S (small subunit) and 50S (large subunit)

Answer 72

the wall consist of glycan chains (parallel rings) linked by peptides (the arrows in-between) the spaces between links are open, porous to large molecules acts like a molecular cage, protecting the cell membrane from osmotic shock

Answer 73

in order from outside to inside LPS (gram negative only) Outer membrane (gram negative only) Cell wall Periplasm Inner membrane/ cell membrane

Answer 74

makes up the bacterial cell wall are never found in human cells, so antibiotics target peptidoglycan synthesis to terminate bacteria the glycan chains of peptidoglycan consist of repeating unit of amino sugar -> NAG and NAM parallel glycan strands are linked by 4 to 6 amino acids the amino acids are attached to the NAM terminal on either strand to create the cross-bridge m-diaminopimelic forms the cross bridge with D-alanine

Answer 75

binds directly to the terminal D-alanine (amino acid) of the peptidoglycan chain, blocking the formation of peptide cross bridges

Answer 76

binds to a bacterial enzyme called transpeptidase -> it is responsible for catalyzing the formation of peptide cross-bridges

Answer 77

thick cell wall, multiple layers of peptidoglycan threaded with teichoic acids will stain purple ex. bacillus anthraces, streptococcus pyogenes

Answer 78

thin cell wall, single layer of peptidoglycan, enclosed by an outer membrane will stain pink has a periplasmic space between the membrane and peptidoglycan ex. e.coli, pseudomonas aeruginosa

Answer 79

the outer membrane consists of phospholipids and lipopolysaccharides (LPS), which is a class of lipids attached to long polysaccharides

Answer 80

from outer to inner - O-antigen -> extends outwards from the core oligosaccharide, not embedded in the membrane - core oligosaccharide-> attached to Lipid A, extends outward but not embedded in the membrane - Lipid A -> embedded in the bacterial outer membrane, fatty acid chains anchor LPS into the membrane, responsible for endotoxic effects when the bacteria is killed

Answer 81

the inner leaflet of the outer membrane that forms a peptide bond with peptidoglycan

Answer 82

outer leaflet of the outer membrane, form Lipid A and polysaccharide chains

Answer 83

Lipid A acts as an endotoxin in lysed cells, so antibiotic treatment can kill cells but can also cause endotoxic shock in patients

Answer 84

mycobacteria contain a unique envelop they have a complex cell wall with peptidoglycan and mycotic acid -> is resistant to staining include human pathogens -> mycobacterium tuberculosis, mycobacterium leprae

Answer 85

blocks the synthesis of arabinogalactan -> is what mycolic acid attaches to

Answer 86

another common external structure on a bacterial cell a helical protein filament whose rotary motor propels the cell in search of a more favourable environment e.coli -> the flagella extends freely outside the cell treponema pallidum/ borrelia burgdorferi -> the flagell wrap around the cell body

Answer 87

movement of the bacteria involves the rotation of the flagella that propels the cell in response to stimuli

Answer 88

counterclockwise rotation moves cells towards attractant

Answer 89

clockwise rotation stops the forward motion, so the cell tumbles and changes direction

Answer 90

responsible for: - the transport of substances in and out of the cell across the membrane - establishment of concentration gradients for energy transfer - support of structure that protrude from the cell (flagella, pili) - signalling and communication - export of toxins and other virulence factors

Answer 91

- adhesins - cell surface proteins - motility - antigenic variation - toxins

Answer 92

cholera toxins

Answer 93

are short attachment pili, they attach to cell surfaces (pili are longer)

Answer 94

facilitates transfer of DNA between cells

Answer 95

are membranous extensions of cytoplasm that secrete adhesion factors called holdfasts -> firmly attach the bacterium in an environment

Answer 96

the DNA containing region of the bacterial cell contains loops of DNA held together by DNA-binding proteins all the loops connect back to a central point called the origin of replication -> it is halfway between the two poles on the membrane

Answer 97

1. DNA replication 2. protein synthesis and expansion of cytoplasm causes cells to elongate 3. septum forms and cell divides transcription and translation occur at top speed while the DNA itself it being replicated = rapid protein production

Answer 98

gene expression can be turned on (induction or up-regulation) or off (repression, or down-regulation) sensing conditions within the cell requires that regulatory proteins bind to specific small-molecular-weight compounds repressor proteins stop gene expression

Answer 99

the enzyme responsible for transcription in prokaryotes

Answer 100

the DNA sequence where transcription starts

Answer 101

transcription, translation, and mRNA degradation can occur simultaneously

Answer 102

a mass of bacteria that sticks to and multiplies on a solid surface can include a single species or multiple collaborating species can grow on organic or inorganic surfaces bacteria in biofilms are very resistant to destruction

Answer 103

1. cellular flagella attach to the monolayer 2. micro colonies form, some cells undergo twitching motility 3. cells secrete a matrix of extracellular polymeric substances (EPS) 4. the biofilm matures, cells communicate by quorum sensing 5. the biofilm dissolves and cells disperse

Answer 104

certain gram-positive bacteria produce destruction-resistant endospores bacteria in endospore form are dormant and require no nutrition or energy endospore state can last for decades or centuries before reactivation may occur ex. bacillus, such as B.anthracis or clostridium, such a c. botulinum and c. tetani

Answer 105

- thrive in moderate environments = temp around 37 degrees, pH slightly alkaline around 7.4, and can be aerobic, anaerobic, or facultative anaerobic ex. E.coli, staphylococcus aureus, salmonella, streptococcus

Answer 106

thrive in extreme environments include thermophiles, halophiles, acidophiles they are rarely pathogenic, the human body doesn't provide extreme conditions needed for survival

Answer 107

need high temperatures to survive -> 40 to 70 degrees

Answer 108

need high salt concentrations to survive higher concentration the seawater

Answer 109

need very acidic conditions to survive

Answer 110

0 to 20 degrees is the temp needed for these bacteria to survive

Answer 111

15 to 45 degrees is the temp need for these bacteria to survive

Answer 112

60 to 120 degrees is needed for these organisms to survive

Answer 113

growth in which population size double at a fixed rate No x 2n

Answer 114

aka. doubling time in an environment with few bacteria but plenty of resources, bacteria will divide at a constant interval called the generation time

Answer 115

1. lag phase 2. log phase 3. stationary phase 4. death phase

Answer 116

bacteria are preparing their cell machinery for growth

Answer 117

growth approximates an exponential curve (this is a straight line on a logarithmic scale)

Answer 118

cells stop growing and shut down their growth machinery while turning on stress responses to help retain viability

Answer 119

cells begin to die at an exponential rate

Answer 120

only a single species is cultured must be done so detailed lap studies can be completed a pure culture can be obtained by touching a single colony with a sterile inoculating loop and inserting the loop into fresh liquid medium, this is done after bacterial cells have formed colonies on agar by using isolation streaking

Answer 121

can be liquid or solid liquid media allows bacteria to move freely solid media is useful to separate mixtures of different organisms

Answer 122

allows for separation of colonies into pure cultures after each section (there's 3) is streaked, the loop is passed through a flame to resterilize it goal is to only have single cells deposited in the new location by the end

Answer 123

another way to obtain pure colonies starts with a liquid culture of bacteria -> transfer 1mL of the bacteria broth to a vial with 9mL of sterile broth -> repeat the dilation into subsequent tubes, 1 mL form the vial before is into 9mL of sterile broth -> the samples are then spread over the surface of the agar plate using a heat sterilized bent glass rod

Answer 124

compounds in the media prevent some types of bacteria from growing favouring the growth of one specific type

Answer 125

species grow equally well, but compounds in the media are metabolized differently, often distinguished by a colour indicator

Answer 126

is both selective and differential the selective agents are bile salts and crystal violet, they prevent the growth of bacteria other than Gram-negative enteric bacteria (group of bacteria that lives in the intestines) the differential agent is lactose, which some bacteria ferment (pink) and others do not (white)

Answer 127

compounds that a microbe cannot make itself but must gather from its immediate environment if the cell is to grow and divide ex. nitrogen, carbon, oxygen, sulfur, hydrogen, phosphorus

Answer 128

the removal of an amino group from an amino acid or other compound

Answer 129

they are broken down into amino acids -> they are then further deaminated to release ammonia -> helps maintain the gut pH (acidic) ammonia can be absorbed into the bloodstream -> liver -> urea -> excreted by kidneys some gut bacteria may influence ammonia levels

Answer 130

nitrogen is need by cells to make proteins and nucleic acids the nitrogen cycle converts nitrogen to various forms -> some bacteria outside the body perform nitrogen fixation to convert nitrogen gas to ammonium ions -> other bacteria transform ammonia to nitrate and then convert nitrate to N2 (nitrogen gas)

Answer 131

conversion of nitrogen gas to ammonium ions ammonium ions can be used for biosynthesis

Answer 132

transformation of ammonia to nitrate (NO3)

Answer 133

conversion of nitrate (NO3) to nitrogen gas (N2)

Answer 134

some bacteria, particularly E.coli, can reduce nitrates (NO3) to nitrites (NO2) in the urine this is related to UTIs and may help diagnosis it

Answer 135

look for the metabolites of nitrite reductase, an enzyme generated by a variety of microorganisms this test has a sensitivity or 25% and specificity of 94% to 100% sensitive catch everything -> find the disease or true positive specificity is exclusive -> confirm only the healthy or true negatives

Answer 136

require oxygen of energy metabolism successfully detoxify reactive oxygen species (ROS) survive only in environments with oxygen

Answer 137

do not require oxygen for energy metabolism generally unable to detoxify ROS, oxygen oxygen toxic survive only in environment without oxygen

Answer 138

aerobic, but ROS can be toxic survive in environments with lower oxygen concentration

Answer 139

aerobic and anaerobic can use oxygen if it is present but can grow without it

Answer 140

anaerobic but less susceptible to ROS, and usually lack catalase prefer anaerobic conditions cannot use oxygen but tolerates its presence

Answer 141

an enzyme produced by bacteria that catalyzes the decomposition of hydrogen peroxide into oxygen and water prevent the accumulation of hydrogen peroxide which can cause potential damage to cellular organelles or tissues the catalase enzyme is an antioxidant

Answer 142

can be used to distinguish between different bacteria, as not all bacteria express catalase during the test, bacteria are exposed to hydrogen peroxide -> bacteria capable of synthesizing catalase will contain bubbles as a result of the reaction ex. positive = micrococcaceae negative = streptococcaceae

Answer 143

- staining = gram positive or gram negative - oxygen respiration - sporulation - mobility

Answer 144

the seven major phyla of bacteria that are known to impact human health and the ecosystem

Answer 145

include firmicutes and actinobacteria they have thick cell walls that resist drying firmicutes produce endospores actinobacteria produce antibiotics

Answer 146

include proteobacteria and bacteroidetes proteobacteria is a very diverse phylum that includes species capable of a wide range of metabolism bacteroidetes are all gram-negative rods, most are obligate anaerobes

Answer 147

share a distinctive form -> tightly coiled cells enclosed by a sheath, with a periplasmic space that contains a very thin peptidoglycan cell wall that runs underneath the sheath along the cell body

Answer 148

are obligate intracellular pathogens that grow as inclusion bodies within host cells

Answer 149

is gram positive has "tough skin" several layers of peptidoglycan supported with teichoic acids can be spore forming or non-spore forming Low "G+C" content (guanine and cytosine)

Answer 150

gram positive broad group that includes antibiotic producers and pathogens peptidoglycan with an additional thick waxy coat -> unusual cell wall lipids like mycotic acid most stain with acid fast stain high "G+C" contents

Answer 151

firmicutes generally grow as well defines rods or cocci (spherical bacteria) some species form endospores -> are resistant to drying, freezing, and chemical disinfectants -> include

Answer 152

are under the phylum firmicutes (gram positive) the are obligate anaerobes the growing endospore swells the end of the cell, giving the cell a club shape the clostridium species include the causative agents of tetanus and botulism also includes c.diff

Answer 153

bacillus anthracis c.diff clostridium botulinum clostridium tetani

Answer 154

GRAM POSITIVE - lactobacillus - lactococcus -> these 2 are lactic acid bacteria, and can grow in the presence or absence of oxygen but cannot use oxygen to respire (aerotolerant) - listeria -> are facultative anaerobic rods all are generally considered catalase positive

Answer 155

GRAM POSITIVE cocci is spherical shaped bacteria enterococcus staphylococcus -> faculty anaerobic, salt tolerant (more cluster shaped) streptococcus -> aerotolerant, many live in the oral cavity, skin, intestine (more linear)

Answer 156

different strains of staphylococci and streptococci are grouped by their ability to hemolyze alpha = party hemolysis (greenish halo on cultures) beta = fully hemolysis (clear halo)

Answer 157

they used to belong to the firmicute phylum but because they have no cell wall they are moved to a new phylum -> Tenericutes cannot stain gram-positive, but still considered gram positive reproduce rapidly in host tissue cause pneumonia or meningitis

Answer 158

cell wall contain mycotic acid and cells stain acid fast are bacilli (rod) and cocci (sphere) shaped gardnerella vaginalis -> bacteria vaginosis corynebacterium diphtheriae -> diphtheria M. tuberculosis M. leprae are facultative intracellular pathogens

Answer 159

GRAM NEGATIVE very diverse and large phylum varied as cocci and spiral cells E.coli Neisseria gonorrhoeae Neisseria meningitis Helicobacter pylori ( reason for stomach ulcers)

Answer 160

GRAM NEGATIVE a pathogenic proteobacteria an obligate aerobic bacilli (rod) related to the enterobacteriaceae P.aeruginosa commonly grows in soil as a decomposer -> in human they cause infection in surgical wounds or form biofilms in the lungs of cystic fibrosis pts.

Answer 161

a proteobacteria family that is composed of nonpathogenic species but also some pathogens - E.coli -> grows normally in the human intestine and produces vitamin K however there are strains of e.coli that cause serious disease - Salmonella - Klebsiella (pneumonia) - Yersinia pestos (bubonic plague)