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Microbio > EXAM 3 > Flashcards

EXAM 3 Flashcards

1
Q

what is the relationship between an infectious disease and a host

A

parasitism

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2
Q

Which of the following contribute to a pathogen’s invasiveness?
-F protein
-hyaluronidase
-endotoxins
-multiple portals of entry

A

hyaluronidase

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3
Q

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the host’s antibodies is called:
-antigenic variation
-virulence
-lysogenic conversion
-cytopathic effect

A

antigenic variation

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4
Q

______on the skin can prevent pathogens from establishing an infection through hair follicles.
However, those same pathogens may be able to get around that protection if they enter
the body through the_______

A

normal microbiota, parenteral

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5
Q

What is the LD50 of this pathogen?

A

10^7

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6
Q

Salmonella is able to enhance its________
by preventing fusion of the phagosome with the lysosome.

A

invasion

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7
Q

Which organism in the table most easily causes an infection?

A

Legionella pneumophila

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8
Q

What is an example of breaking the chain of infection by decreasing the number of susceptible hosts

A

Vaccination

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9
Q

Transmission of the corona virus by coughing and sneezing of an infected person in a closed
small space is what?

A

Direct transmission

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10
Q

A person carrying an infectious microorganism, may be infectious at:
-Incubation period
-Period of illness
-Period of convalescence
-All of the above

A

All of the above

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11
Q

What is an epitope?

A

Part of the antigen that binds the antibody

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12
Q

Which of the following cells would be safe from a natural killer (NK) cell’s cytotoxicity?
-a self-cell presenting with MHC I molecules
-a cancer cell
-a self-cell with a viral infection
-a self-cell without MHC I molecules

A

a self-cell presenting with MHC I molecules

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13
Q

Which of these is a purpose of fever? Choose the best answer.
-makes pathogenic microbe reproduction harder
-recruits phagocytes to the site of the infection
-prevents the physical entry of pathogens into the body
-responsible for perforin-mediated cytotoxicity

A

makes pathogenic microbe reproduction harder

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14
Q

What is the function of resident flora in immunity

A

take away habitat and nutrient availability from pathogens

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15
Q

Phagocytes bind to pathogen-associated molecular patterns (PAMPs) via:

A

pathogen-recognition receptors (PRRs)

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16
Q

How many antigens can bind IgM pentamers?

A

10

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17
Q

Antibody-dependent cell mediated toxicity (ADCC) is effective in removing what kind of
antigen?

A

large eukaryotic pathogens

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18
Q

Release of histamine by mast cells at the site of the wound causes
-Inux of phagocytotic cells to the wound area
-Edema (swelling)
-Redness
-All of the above

A

All of the above

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19
Q

What is the difference in the outcome between T-cell dependent and T-cell independent B
cell activation

A

T-cell dependent pathway creates memory cells that can fight the pathogen during
secondary infection

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20
Q

Pathogens that are super antigens create toxicity by

A

Creating excessive immune response, inflammation and fever

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21
Q

What is commensalism

A

-when an organism benefits from another without harming the other
EX:
-bacteria that lives on our skin doesnt affect us
-staphylococcus aureus
-skin microbiota

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22
Q

What is mutualism

A

-when two organisms benefit from each other
EX:
-E. coli benefits from living in our large intestines by getting nutrients. We benefit from E. coli because it helps us digest food
-escherichia coli
-gut micrbiota

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23
Q

What is parasitism

A

When an organism benefits from an organism while harming it
EX:
-streptococcus pyogenes (Strep throat) benefits from us but causes us to get sick etc.

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24
Q

What is symbiosis

A

two organisms living in the same environment

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25
Q

What is a pathogen

A

a microbe agent that cause disease

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26
Q

What is the difference between infectious and non-infectious disease

A

INFECTIOUS DISEASE: caused by direct effect from a pathogen (possible to pass from person to person)
EX: the flu, measles, strep throat, COVID

NON-INFECTIOUS DISEASE: caused by factors such as genetics, anatomical differences, radiation, or other environmental factors (not passed from person to person)
EX: cancer, diabetes, alzheimers

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27
Q

Whats the difference between communicable, non-communicable, and zootonic infectious diseases?

A

COMMUNICABLE: contagious disease that can spread from person to person (COVID)

NON-COMMUNICABLE: infectious disease that is not passed from person to person (LYME DISEASE)

ZOOTONIC DISEASE: pathogen transferred from animal to human (LYME DISEASE from ticks)

28
Q

What kind of symbiosis is staphylococcus epidermidis?

A

mutualism because:
-promotes immune response to harmful microorganisms
-prevents growth of harmful microorganisms
-contributes to skin integrity
-host provides nutrients

29
Q

What is microbiota

A

community of microorganisms living in our body

30
Q

What is the difference between transient and resident microbiota?

A

TRANSIENT MICROBIOTA: present for days, weeks, months
RESIDENT MICROBIOTA: permanently colonize the host and do not cause disease under normal conditions

31
Q

what is microbial antagonism

A

-competition for space and nutrients
-production of substances that are harmful to pathogens
-promote immune response to harmful microorganism

32
Q

What is an example of opportunistic pathogen

A

1) a patient who has been taking antibiotics for a long time, is suffering from diarrhea caused by Clostridium difficile

2) Pseudomonas aeruginosa infections in a patient suffering from cystic fibrosis

33
Q

A disease-causing microbe that is able to infect a healthy host is best categorized as:
-opportunistic pathogen
-primary pathogen
-normal microbiota
-transient microbiota

A

primary pathogen

34
Q

What is pathogenicity and what are the 4 stages

A

the ability of a microbial agent to cause disease

1) exposure/contact (gain access to host tissue)
2) adhesion (attachment to the host cells)
3) invasion (penetrating tissue and cells)
4) infection (multiplication of the pathogen)

Eat, Apple, Ice cream, Inside

35
Q

How does mycobacterium tuberculosis invade your cell

A

-macrophages in alveoli engulf bacteria but mycolic acid protects bacteria
-continue reproducing in the phagosome
-break open the phagosome and release in cytosol
-toxins from bacteria kill macrophages
-release the bacteria and infection of more cells

36
Q

What is infection and what are the 3 kinds

A

a successful multiplication of the pathogen

1) local (confined to small part of body)
2) focal (spread of local infection to another location)
3) systemic (spread throughout the body)

EX: microorganisms that colonize teeth plaques, contribute to heart disease

37
Q

What is virulence/virulence factors? What are the 6 factors?

A

VIRULENCE: the ability of a microorganisms to infect and cause damage to its host

VIRULENCE FACTORS: determine the extent and severity of disease
-capsules
-cell wall components
-adhesins
-exoenzymes
-toxins
-antigenic variation

38
Q

What is infectious dose and lethal dose? what does ID50 and LD50 mean?

A

infectious and lethal dose are a method to quantify virulence of a pathogen

ID50: the amount of cells or virions required to infect 50% of hosts introduced to pathogen

LD50: the number of pathogenic cells, virions, or amount of toxins required to kill 50% of infected animals

39
Q

how do microorganisms escape the immune response

A

-bacteria use a variety of virulence factors to evade phagocytosis by cells of the immune system

EX: many bacteria produce capsules, which are used in adhesion but also aid in immune evasion by preventing ingestion by phagocytes

40
Q

What is antigenic variation

A

pathogens alter their surface antigens (and antibodies produced by host cells are rendered ineffective)

41
Q

What is the difference between antigenic drift and shift?

A

ANTIGENIC DRIFT: a more GRADUAL change of antigens

ANTIGENIC SHIFT: a SUDDEN change of antigens prompted by a co-infection of two viruses with different antigens

42
Q

Give an example of nosocomial factors

A

when someone uses/is exposed to antibiotics for a long period of time

43
Q

What is the difference between signs, symptoms, and syndrome?

A

SIGNS: objective and measurable characteristics (body temp, heart rate, blood pressure, breathing rate)

SYMPTOMS: something felt or experience by patient but cant be clinically confirmed/ not measurable (nausea, loss of appetite, pain)

SYNDROME: a specific group of symptoms characteristic of a particular disease (Irritable bowel syndome)

44
Q

What is morbidity/morbidity rate and what are the two aspects

A

MORBIDITY: number of cases of a disease

MORBIDITY RATE: number of people affected in relation to the total population in a given time period

TWO ASPECTS :
1) INCIDENCE: number or proportion of new cases during a specific time period (indicated speed of disease)

2) PREVALENCE: number or proportion of individuals with a particular illness in a given population during a specific time period

45
Q

What is mortality/mortality rate

A

MORTALITY: number or deaths due to disease

MORTALITY RATE: number of deaths from a disease in relation to a population in a given time

46
Q

What are the 4 patterns of incidence?

A

1) SPORADIC DISEASE (occurs occasionally in population)-typhoid fever

2) ENDEMIC DISEASE (constantly present in a population)- common cold

3) EPIDEMIC DISEASE (acquired by a larger number of hosts than expected in a given area in a short time) -influenza

4) PANDEMIC DISEASE (worldwide epidemic)-AIDS/COVID

47
Q

What are the 5 different periods of disease in order

A

1) incubation period
2) prodromal period
3) period of illness
4) period of decline
5) period of convalescence

48
Q

What is chain of infection and the 5 steps of it

A

-it explains how an infectious agent leaves it reservoir, moves to new host and causes infection to new host
-any action to break this chain can stop/reduce the spread of disease

1) reservoir
2) portal of exit (how it gets to another person)
3) mode of transmission
4) portal of entry
5) susceptible host

49
Q

What is the difference between innate and adaptive immunity

A
50
Q

What do leukocytes do and what are the two categories

A

they help with cellular defense

1) GRANULOCYTES (characterized by numerous granules visible in the cytoplasm)

2) ARGANULOCYTES (lack granules)

51
Q

What is phagocytes and how do they recognize their targets?

A

-Phagocytes are cells whose main function is to find, ingest, and kill pathogens (WBC or WBC derivatives)

can recognize targets by
1) OPSONIZATION: process of tagging oh the pathogens so they can be recognized by phagocytes

2) PATHOGEN ASSOCIATED MOLECULAR PATTERNS (PAMPs): groups of molecules common on pathogenic microorganisms

52
Q

What are phagocytotic cells

A

-release of toxic molecules that damage the microbes

-phagocytosis and removal of the microbes

-release of cytokines causing inflammation

-presenting antigens on the cell surface

53
Q

What are natural killer cells and what are the two major mechanisms

A

-Identify infected cells without major histocompatibility class I molecules and induce programmed cell death of infected cells or cancerous cells

TWO MAJOR MECHANISMS
1) release of cytotoxins proteins and cytokines that trigger apoptosis in the target cell

2) perforin-creates pores in the membrane of the target cell

54
Q

What are the signs of inflamation

A

-erythremia (redness)
-edema (swelling)
-heat
-pain
-fever (pyrogens)

55
Q

What is an immunogen

A

an antigen that causes the body to produce specific antibodies

56
Q

what is an antibody

A

molecules produced by the cells of the immune system that bind to immunogens and mark them for destruction and removal

57
Q

What is the difference between MHC I and MHC II

A

MCH I: found on all nucleated self cells

MCH II: found on antigen presenting cells

58
Q

What are antigen presenting cells

A

macrophages or dendritic cells

59
Q

what is pseudomembrane

A

a layer of dead cells

EX: diphtheria

60
Q

what is granuloma

A

defense mechanism of the immune cells that create walled-off lesions to prevent spread of infection

EX: tuberculosis

61
Q

what are the defense mechanisms of the respiratory system

A

-mucociliary escaltor
-macrophages in the alveolar sacs
-nasal cavity contains mucus membrane with sticky and salty mucus with lysozymes
-traps bacteria and particles in nose hair

62
Q

what are defense mechanisms in the digestive tract

A

-salivary gland produce saliva
-normal microbiota
-mucus membrane
-acidity of stomach
-peristalsis movement of materials through the gastrointestinal tract also helps to move transient pathogens out of the body

63
Q

Which blood agar plate is alpha, beta, and gamma hemolysis?

A

left to right: beta, alpha, gamma

64
Q

How is the mannitol agar plate (MSA) differential and selective

A

Differential
-contains mannitol
-fermentation of mannitol produces acids
-ph indicator turns yellow in acidic environment, no color change is basic

Selective
-high concentration of NaCl selects for members of the genus staphylococcus that are halotolerant

65
Q

How is the eosin-methylene blue agar plate (EMB) selective and differential

A

Differential
-contains methylene blue that prevents growth of gram positive bacteria

Selective
-contains lactose/sucrose
-fermenters produce pink colonies
-high fermenter produces a green metallic colony

66
Q

How is endo agar differential and selective

A

Selective
-only grows gram negative bacteria
-sodium sulfite and basic fuchsin make this medium selective by suppressing gram positive bacteria

Differential
-pink is positive for lactose fermenting
-colorless is negative for non-fermenting

Microbio (5 decks)

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