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I&I > Microbiology: A Focus on Bacteria, Fungi, and Viruses > Flashcards

Microbiology: A Focus on Bacteria, Fungi, and Viruses Flashcards

1
Q

How do “bad” pathogens arise from human microbiome

A

dietary changes
stress
antibiotics

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2
Q

True/false: Majority of pathogens are non-pathogenic

A

true

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3
Q

What do pathogens do to help them survive?

A

They constantly evolve by either losing or gaining traits over time

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4
Q

What is the incubation period

A

The time it takes the pathogen to enter the body and show the first symptom to appear

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5
Q

What does the incubation period depend on

A

health of host
growth rate of pathogen
degree of exposure

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6
Q

What is the timeline of infection

A

incubation period –> onset of illness –> period of invasion –> convalescent period

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7
Q

What are the different types of infections

A

Acute
Chronic
Latent (persistent)

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8
Q

What is an acute infection

A

Symptoms develop quick
Clears quickly
Host has immunity for reinfection
ex. strep throat

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9
Q

What is chronic infection

A

Symptoms develop slowly
Can last months to years
ex. tuberculosis

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10
Q

What is latent (persistent) infection

A

Illness never goes away
It becomes formant in the body and can be awakened with low immunity
ex. syphilis, typhoid, fever, etc.

Carriers: the host may not show symptoms but they spread it to others

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11
Q

What is horizontal transmisson

A

person to person (horizontal)
ex. blood, saliva, stds, urine

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12
Q

What is vertical transmissoin

A

Mother to baby via breast milk, delivery, placenta

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13
Q

What is a vector

A

An animal or arthropod that caries a pathogen and can transfer it to humans
ex. rabies virus transmitted by animal bite

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14
Q

What is virulence?

A

the degree of pathogenicity of a pathogen (bacteria, fungi, or virus) and is determined by its ability to invade and multiply within the host causing disease

They grow and thrive at the expense of the host

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15
Q

what is a strict pathogen

A

always causes disease

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16
Q

What is an opportunistic pathogen

A

part of normal microbial flora
takes advantage of a weakened immune system
caused by the disruption in the microbial flora
breached barrier introduced by a wound

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17
Q

Bacterial Characteristics shapes

A

Maintained by cell wall of bacteria composed of peptidoglycan

No nucleus –> chromosome forms a structure called a nucleoid

No membrane-bound organelles (prokaryotic)

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18
Q

What are the main shapes of bacteria

A

cocci
bacilli
spiral
pleomorphic (no defined shape)

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19
Q

What is the cocci shape

A

Spherical bacteria

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20
Q

What are the different variations of cocci?

A

Single organisms (cocci)
Pairs (diplococcus)
Chains (streptococcus)
Clusters (staphylococcus)
Tetrads
Sarcina (cube of eight cocci)

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21
Q

What is bacilli

A

Rod shape

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22
Q

What are the variations of bacilli

A

Single (bacilli)
Double (diplobacilli)
Chain (streptobacili)
Palisades

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23
Q

What is the intermediate shape between coccus and a bacillus

A

coccobacilli

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24
Q

What are the shapes of spiral bacteria

A

Vibrio
Spirillum
Spriochete

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25
Q

What is vibrio

A

curved or comma-shaped rod

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26
Q

What is spirllum

A

Thick, rigid spiral

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27
Q

What is spirochete

A

thin, flexible spiral

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28
Q

What is pleomorphic

A

do not have any characteristic shape
can change their shape
also can be a combination of shapes

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29
Q

What cell retains crystal violet from iodine

A

gram +

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30
Q

What cell does not retain crystal violet and appears transparent

A

gram -

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31
Q

Which cell has a thick multi-layered peptidoglycan layer

A

gram +

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32
Q

Which cell structure contains lps

A

gram -

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33
Q

What is LPS

A

only produced by gram (-)
Consists of lipid and carbohydrate
Helps bacteria cause disease

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34
Q

What are cell wall components

A

LPS (only in gram -) and peptidoglycan (sugar and amino acids)

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35
Q

which cell type has an outer membrane that prevents crystal violet penetration

A

gram (-)

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36
Q

Which cell develops resistance more quickly

A

gram (-)

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37
Q

Which cell is more resistant to antibodies due to impenetrable cell wall

A

gram (-)

38
Q

Which cell lacks peptidoglycan

A

gram (-)

39
Q

What are acidophiles

A

bacteria that grow optimally at pH values around 2

40
Q

What are alkalophiles

A

only grow well at pH values near 10

41
Q

Aciduric (acid tolerant)

A

Can survive acidic conditions but not necessarily grow under those conditions

42
Q

Psychrophiles

A

Prokaryotes that grow very poorly at temperatures above 15 celcius

43
Q

Thermophiles

A

thrive at 100 degrees C

44
Q

What are the components of a bacterial cell structure

A

Capsule
Cell wall
Cytoplasmic membrane
Pili
Flagella
Nucleoid
Cytoplasm
Ribosomes

45
Q

What is capsule

A

covers the outer layer of the cell wall
composed of polysaccharides
mediates attachment of bacterium to host tissues
can inhibit phagocytosis by neutrophils and macrophages –> virulence factor for some bacteria

46
Q

Strep mutans

A

one of the causative agents of dental caries
attaches to tooth surfaces via a capsule

47
Q

What is slime layer

A

some bacteria have a loosely adherent colloidal material that they secrete

usually similar to the capsule

48
Q

What is a pili (aka fimbriae)

A

Extend from cell surface
Pili: long hair-like tubular microfibers
Responsible for: attachment and transfer of DNA & motility

only in gram (-) only!!

49
Q

What is the flagella

A

extend from interior cell body
Responsible for: motility, also sense certain temperature and chemicals/metals

present in both gram + and -

50
Q

Bacterial Growth Curve phases

A

lag phase –> exponential (log) phase –> stationary phase –> death phase

51
Q

What is the lag phase

A

initial phase characterized by cellular activity BUT NOT GROWTH

cells increase in size, but no cell division

52
Q

Exponential (log) phase

A

cells divide by binary fissions & metabolic activity high

53
Q

Which bacteria growth phase are antibiotics and disinfectants most effective in?

A

Exponential (log) phase

54
Q

Stationary phase

A

Bacterial cell growth reach a plateau

Number of dividing cells equal the number of dying cells

No overall population growth

55
Q

Death phase

A

Number of living cells decreases exponentially

Population growth experiences sharp decline

56
Q

Bacterial spores

A

gram (+) bacteria only form spores
especially under adverse environmental conditions

57
Q

What is the importance of spores

A

structure of spore protects its DNA from intense heat, radiation, and attack by most enzymes and chemical agents

So resistance to environmental factors –> can exist for centuries

Difficult to decontaminate with standard disinfectants or autoclaving

58
Q

Aerobic bacteria

A

require oxygen for basic survival, growth, and reproduction

59
Q

Anaerobic

A

don’t require oxygen for growth

60
Q

Fermentation

A

Anaerobic conditions only

Conversion of pyruvate to various end products (ethanol and lactic acids)

61
Q

True/false: aerobic and anaerobic conditions both involve glycolysis

A

True

62
Q

Which cell has peptidoglycan and what does peptidoglycan do

A

gram (+)
Induce fever/inflammation

63
Q

What does LPS do? (low vs. high doses)

A

Low doses: activates immune response and triggers fever

High doses: extreme fevers, septic shock, skin lesions (fatal)

64
Q

Two ways bacteria cause disease

A

release of exotoxins
bacteria inhibit phagocytosis of immune cells

65
Q

release of exotoxins (polypeptides)

A

receptor-binding proteins that cause cell death or change in function

Cytolysis bursting of host cell from osmotic pressure

66
Q

What type of bacteria releases exotoxins

A

gram - and gram +

67
Q

What do exotoxins do

A

releases: enzymes, gas, acids, toxins

toxins: cause cell lysis and can cause degradation of tissue by immune response

Can be encoded on a plasmid or a bacteriophage

68
Q

Transformation

A

introduction, uptake and expression of foreign genetic material

69
Q

Conjugation

A

Transfer of DNA via plasmid from a donor cell to a recipient cell

Involves pilius

70
Q

Transduction

A

bacterial DNA is moved from one bacterium to another by a virus

71
Q

Quorum sensing

A

bacteria’s way to communicate

72
Q

Fungi

A

diverse group of free-living eukaryotic micro organnisms
may be unicellular or multicellular

73
Q

Fungi in our body

A

controlled by competent immune system and multiplies when conditions are favorable

74
Q

obligate intracellular parasites

A

viruses

75
Q

Are viruses alive

A

me dont think so because”
do not reproduce, do not maintain metabolism to gain energy on their own

76
Q

Different virus structures

A

Naked capsid virus or enveloped virus

77
Q

What is naked capsid virus (non-enveloped)

A

typically more virulent
usually cause host cell lysis
cell lysis= most common exit mode from host cell
Does not have extra lipid membrane

Antibodies are generally sufficient for protection against these infections

78
Q

True/false: Non-enveloped capsid virus is more resistant to extreme pH, heat, dryness, and simple disinfectants

A

true yuhh

79
Q

How does naked capsid virus spread

A

spread on fomites, hand to hand, and by small droplets

80
Q

Where can naked capsid virus grow

A

can survive in the gastrointestinal system because of their resistance to low pH and bile detergents

81
Q

Characteristics of enveloped virus

A

typically less virulent

don’t always cause cell lysis during cell exit

contain an outer membrane that surrounds the capsid –> can use host cell membrane itself to assemble their membrane –> process avoids cell lysis and helps enveloped viruses escape from host’s immune system

82
Q

Which type of virus is relatively less sensitive to environmental conditions

A

enveloped virus

83
Q

what virus can spread in large droplets and secretions or by organ transplantation and blood transfusion

A

enveloped virus

84
Q

Virus classification is based on

A

size, morphology, nucleic acid, disease they cause, means of transmission

85
Q

Morphology of a virus is based on

A

size and shape

86
Q

Chemical composition and mode of replication

A

may consist of DNA or RNA
may be single or double stranded
may be linear or circular

87
Q

Characteristics of DNA viruses

A

mostly double stranded
replication occurs in the nucleus
has to be transcribed prior to being synthesized into proteins

Exception: a few DNA viruses can replicate in cytoplasm because they carry polymerases

DNA –> RNA –> mRNA –> proteins

88
Q

Characteristics of RNA viruses

A

Mostly single stranded
replication occurs in the cytoplasm
can use its RNA to immediately synthesize proteins

RNA –> mRNA –> Proteins

89
Q

What is a positive strand of RNA

A

RNA virus that serve as mRNA and can immediately be translated into proteins

RNA/mRNA –> proteins

90
Q

What is a negative strand of RNA

A

Viral RNA must first be transcribed into mRNA then can be translated into proteins

RNA –> mRNA –> proteins

91
Q

What are retroviruses

A

reverse normal transcription

reverse transcriptase will transcribe the RNA from the virus into DNA and then incorporates it into the host’s cell

DNA <– RNA

92
Q

Viral Replication APURAM

A

study on slides for more detail lol

Attachment
Penetration
Uncoating
Replication
Assembly
Maturation
Release

I&I (5 decks)

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