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MICR 2420 > Final Exam > Flashcards

Final Exam Flashcards

1
Q

Traits shared by ‘prokaryotes’

A

-70S ribosomes
- Complex cell walls
*-Majority have circular genomes in compact nucleoid
- Share many metabolic traits

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2
Q

Differences between Bacteria and Archaea

A
  • rRNA gene sequences
  • Membrane lipids (ether-linked isoprenoid lipids
    forming mono/bilayers)
  • pseudopeptidoglycan
  • Domain Archaea lacks known pathogens
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3
Q

Archaea grow within a wider range of

A
  • temperature
  • osmolarity
  • pH
  • other environmental conditions
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4
Q

Bacterial drug resistance mechanisms

A
  1. Efflux pump (multidrug resistant
  2. Target modification spontaneous mutation)
  3. Secreted - degrative enzymes - enzymatic alteration
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5
Q

How does horizontal gene transfer for antibiotic resistance spread?

A

Conjugation of plasmids. Using sex pilus 2. Transduction by bacteriophages 3. Transformation uptake of dna released by lysis

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6
Q

‘What practices underlie our problem of extensive
antibiotic resistance?

A

Innapropriate/overuse
Patient non compliance
Non prescription purchase
Agricultural use

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7
Q

‘What could lead to the development of a superinfection

A

‘Broad spectrum anti microbial

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8
Q

What strategies can counter antibiotic resistance ?

A

Chemistry modification of existing drugs
Integrated resistance monitoring
Vaccine R and D
Combbjnation therapy
Prohibit agriculture use

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9
Q

What do mycorrhizae do? ___ w

A

➢ Fungal hyphae surround/enter
Impact car
Bon cplant roots → enhance plant’s uptake of water anD minerals while obtaining sugars from plants
➢ critical to reforestation efforts
Ye modelling

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10
Q

Booster shots to increase

A

memory cells and the level of immunity

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11
Q

Unvaccinated surrounded by a 70% vaccinated/immune
population are protected by

A

herd immunity

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12
Q

The most distinctive structure of
archaea is their

A

ether-linked
membrane

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13
Q

ether-linked
membranes can form in a
_____ and use ___ glycerol

A

monolayer, L

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14
Q

Archaea lack ____ molecules

A

peptidoglycan

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15
Q

some _____ archea who
have pseudopeptidoglycan

A

methanogens

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16
Q

Genomes of archaea resemble
those of bacteria in __ ____ and ____

A

gene size and
density

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17
Q

what of archaea is similar with those of eukaryotes

A

DNA and RNA polymerases
and transcription factors are
similar to those of eukaryotes

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18
Q

eukaryoticarchea with methanogens

A

Serve a key energetic role in ecosystems
by providing for anaerobic H2 removal
through the production of methane

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19
Q

Haloarchaea supplement their metabolism
with light-driven ion pumps, called

A

bacteriorhodopsin

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20
Q

Methanogens can use a diversity of substrates to produce
methane (4)

A

Carbon dioxide:
Acetic acid:
Methanol:
Methylamine

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21
Q

Methanogens grow in

A

soil, under
permafrost, in animal digestive tracts,
and in marine floor sediment

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22
Q

major source of methanogens
is

A

landfills

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23
Q

methane
hydrates

A

Methane produced by methanogens deep underground is trapped in ice

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24
Q

Protozoa are ____- that are single-celled heterotrophs.

A

Protozoa are protists that are single-celled heterotrophs.

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25
Q

mycoses

A

illness caused by fungi

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26
Q

Most molds are made of

A

hyphae

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27
Q

the three types of hyphae are

A

septate, coenocytic, pseudohyphae

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28
Q

important yeast pathogens

A

Candida albicans,
Cryptococcus neoformans

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29
Q

moulds are involved in

A

composition of organic
matter, allergies, asthma, Aspergillus
fumigatus

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30
Q

Basic structures of moulds

A

Spores (or conidia) are produced in
chains on a conidiophore (a form of
aerial hyphae

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31
Q

spores have

A

Sterol-containing membrane

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32
Q

fungal cell wall inner

A

Inner cell wall is relatively conserved,
made up of chitin and branched β-1,3-
glucan

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33
Q

fungal cell wall outer

A

Many yeasts (including Saccharomyces
and Candida species) have an outer cell
wall comprised of the polysaccharide
mannan and mannoproteins
35

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34
Q

Symbionts

A

Form critical symbiotic relationships with plants (i.e. mycorrhiza), algae
(i.e. lichens), and insects

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35
Q

invasive pathogens (in immunosuppressed
patients) with very high mortality rates

A

Candida, Cryptococcus, Aspergillus42

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36
Q

protists are

A

polyphyletic and highly divergent

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37
Q

The algae are

A

autotrophic protists

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38
Q

algae perfom

A

Perform oxygenic photosynthesis via chloroplasts some produce toxins

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39
Q

algae have

A

Rigid cell walls: cellulose +
glycoprotein layer …
OR sometimes silica

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40
Q

protozoa are the predators of the microbial world, engulfing prey through _____
(heterotrophs).

A

phagocytosis

41
Q

protozoa lack

A

cell walls

42
Q

Different methods of locomotion:

A

➢ Cilia beat like oars and are not like prokaryotic pili
➢ Flagella move like fishes’ tails unlike prokaryotic flagella
➢ Amoeboid movement using pseudopodia → evolved separately in different lineages

43
Q

Primary algae

A

ancestral pre-
eukaryote cell engulfed an
ancestral phototrophic
cyanobacterium, which became
the chloroplast
Secondary algae - engulfment
of a primary phototrophic
endosymbiont (e.g. algae) by a
mitochondria-containing
eukaryotic cell
Distinguishing feature: the
chloroplast is surrounded by
two membranes

44
Q

Secondary algae

A

engulfment
of a primary phototrophic
endosymbiont (e.g. algae) by a
mitochondria-containing
eukaryotic cell
Distinguishing feature: the
chloroplast is surrounded by
two membranes

45
Q

Oxidations and reductions of
inorganics

A

lithotrophy and anaerobic respiration

46
Q

The Winogradsky column is stable for years with only

A

light and gas exchange

47
Q

The Winogradsky columns are maintained by

A

1.Phototrophic microbes
2. Heterotrophic microbes
3. Lithotrophic bacteria & archaea
4. Anaerobically respiring microbes
5. Fermentative microbes

48
Q

lithotrophic archaea are
major _______
producers beyond the
_______ (aphotic
zone)

A

marine primary, euphotic zone

49
Q

oligotrophic

A

low conc of minerals and plants

50
Q

eutrophic

A

High conc of minerals and plants

51
Q

The Great Plate Count Anomaly

A

solation/identification and
viable plate counting will not give an accurate characterization of
community composition

52
Q

metagenomics

A

is most often used to characterize microbial communities → culture-independent DNA purification and
sequencing (rRNA gene (SSU (16S)) or shotgun (sequencing
everything))

53
Q

microbes increaswe

A

Increase [essential nutrients]
that limit growth of primary
producers

54
Q

Biotechnological applications of the microbes:

A

Harnessing the microbes:
➢ *biotechnology, biocontrol & bioremediation
➢ food, beverage and pharmaceutical industries (antibiotics & vaccines)

55
Q

Bioremediation

A

the use of life forms (often microbial) to
degrade pollutants to nontoxic forms
Through oxidation for energy generation
➢ Or reduction, in fermentation or as terminal
electron acceptors (anaerobic respiration)
Most often exploiting the phenomenon that collectively,
heterotrophic microbes degrade (oxidize) everything

56
Q

Urban wastewater treatment plant

A
  1. Physical separation
  2. Aerobic heterotrophy
  3. Anaerobic heterotrophic digestion
    ➢ CH4 from methanogens: burned, or used for energy
57
Q

Fermentation

A

anaerobic process that occurs in some
HETEROTROPHIC bacteria and in yeasts -> no electron
transport chain (ETC) involved
Myriad of desirable
and undesirable
products (off flavours)

58
Q

Alcoholic fermentation in beer and wine

A

Fungal metabolism: heterotrophs and saprophytes are not
selective in what their secreted enzymes degrade nor the
nature of their organic substrate

59
Q

Spoiled foods from other heterotrophs

A

– anaerobic, toxigenic, endospore-forming
Gram positive bacterium Clostridium
botulinum
Molds
- causes intoxication or infant infections

60
Q

Unseen dangers: Food contaminated with pathogens can lead

A

lead to
food-borne infections (bacterial and viral) or
intoxications (bacterial)
-The Gram positive bacterium
Listeria monocytogenes is
ubiquitous in the environment
The organism is a facultative
psychrophile
➢ it can grow at 4° C
➢ primarily a problem in ready-
to-eat foods

61
Q

Virions

A

are the extracellular, and
infectious, form of the virus

62
Q

filamentous viruses have

A

helical
symmetry

63
Q

classification of viruses

A

damiy, sub family, genus, species

64
Q

Viruses are classified or identified based on a combination of
criteria:

A

Nature of genome – including nature, shape,
strandedness and whether it is segmented
2. Capsid symmetry
3. Envelope - +/-
4. Size of viral particle
5. Host range

65
Q

Viral infection and reproduction:

A
  1. attachment
  2. penetration
  3. uncoating
    4.biosynthesis
  4. assembly
  5. release
  6. maturation
    ( A PUB ARM
66
Q

Bacteriophage life cycle

A

Attachment to specific host cell receptors
* Phage genome is injected through the cell wall and membrane
and the capsid is shed
* receptors play a role in normal cell function

67
Q

Bacteriophages can undergo two different types of life
cycles

A
  1. Lytic cycle
    - rapid phage replication & lyses / kills host
    - lytic phages, e.g. T2, T4
  2. Lysogenic cycle
    Temperate phage infects & inserts its
    DNA into host chromosome
    - activated to excise and follow lytic
    life cycle by certain triggers
    - e.g. phage λ
68
Q

Coronavirus virion

A
  • Spike protein (S) – trimers provide specificity for cellular entry
    receptors
  • Envelope (E) – ensure incorporation into viral particle during
    assembly
  • Membrane (M) – ensure incorporation into viral particle during
    assembly
  • Nucleocapsid (N) - +ssRNA encapsidation
69
Q

Culturing Viruses requires

A

a host cell
Two types of Bacteriophage culture systems
* batch culture (in liquid)
* isolated plaques on a bacterial lawn (on a plate

70
Q

Cyticidal effects of viral
replication

A

destruction of host cells in
culture results in the
formation of plaques

71
Q

vaccine types

A

Live attenuated
Inactivated/killed
Subunit (Toxoid, polysaccharide,
conjugate)

72
Q

NRM

A

non-replicating mRNA

73
Q

SRM

A

self-replicating mRNA

74
Q

Paul Ehrlich

A

proposed the principle of selective toxicicity-Used (small molecule) screening,
still used today

75
Q

Sir Alexander Fleming

A

penicillin, produced by the fungus
Penicillium notatum, in 1928

76
Q

Drugs target critical and unique aspects of the
bacterial cell physiology:

A

they are selectively
toxic
➢ Cell wall (i.e. peptidoglycan)
➢ Cell membranes (e.g. G-negative OM)
➢ DNA synthesis (e.g. DNA gyrase)
➢ RNA synthesis
➢ Protein synthesis (e.g. ribosomes)

77
Q

Chemical modifications to a “first generation” antibiotic may

A

increase spectrum of
activity, acid stability, and/or thwart some mechanisms of resistance (e.g. β-lactamase)

78
Q

Combinatorial Therapy

A

Two treatments (e.g. Antibiotic A + chemical B)
* Additive – Both have a (probably) separate effect
* Antagonistic – More growth
* Synergistic – Both have a (probably) related effect

79
Q

Rhizobia + legumes

A

The rhizobia (e.g. Rhizobium spp.) form nodules on legume roots and fix nitrogen
only in this symbiosis (“diazotrophy”)

80
Q

Digestion in ruminants

A

plant fiber → cellulose (fungi)
➢ Cellulose → Sugar + H2 + CO2 (cellulolytic bacteria)
➢ (H2 and CO2 microbial fermentation products are used by
methanogens** to produce methane)
The rumen is
anaerobic
➢ Anthropogenic
(human made) GHG

81
Q

ratio of human to microbial cells

A

1:1.4

82
Q

Physical barriers

A

epithelium, mucociliary blanket,
hair/eyelashes, skin (shedding)

83
Q

Mechanical barriers

A

blinking, mucociliary escalator, swallowing,
coughing, sneezing, urination, diarrhea

84
Q

microbiome

A

bacteria of skin, upper respiratory tract,
gastrointestinal tract, and genitourinary tract

85
Q

Chemical barriers

A

Tears, toxic lipids (oils), sweat, lysozyme in tears, saliva & mucous

86
Q

Koch’s Postulates

A

establishing the causative agent of infectious disease
Koch developed the technique
of single colony isolation on
solid media

87
Q

Break in/find a key: stick to, breach the epithelial barrier (and subsequent tissues), exploit an
existing entry system

A

Adhesins - pili, capsules, LPS help attach/ resist dislodging; viral
coat/envelope proteins facilitate cell attachment AND penetration
❖ Degradative enzymes - bacterial exotoxins,
Break in/find a key: stick to, breach the epithelial barrier (and subsequent tissues), exploit an
existing entry system
❖ rely on a physical/health breakdown or indwelling device

88
Q

Mycobacterium tuberculosis

A

hijacks phagocytic cells
(alveolar macrophages) → resists phagocytic killing,
multiplying in alveolar macrophages → chronic
inflammation gives tubercles 24
“immunopathogenesis”

89
Q

average person inhales __ microbes per minute

A

8

90
Q

AZT

A

recognized by, blocks reverse
transcriptase activity

91
Q

Fuzeon

A

inhibits fusion of HIV envelope with host cell
plasma membrane

92
Q

Key leukocyte players:

A

T lymphocytes – variety of subtypes
➢ coordinate, regulate (TH, Treg); provide cell-mediated immunity (TC);
differentiate into memory cells
B lymphocytes
➢ Produce plasma cells → antibodies; produce memory cells
virtually limitless antigen structures (and
their epitopes) can be recognized
from previous exposure**
recognizes microbiota but tolerates them in
their normal body sites

93
Q

Acquired immune response always includes ____ activation

A

\ B cell \

94
Q

May also
secrete IgM in

A

T-cell independent activation

95
Q

epitope presented on MHCI of infected cell or MHCII of APC

A

mchci

96
Q

Antibodies opsonize antigens:

A

Neutralize viruses
➢ Neutralize toxins
➢ ↑ phagocytic efficiency through Fc binding

97
Q

IgM

A

first responder to a new epitope; pentameric → 10 antigen-binding sites

98
Q

IgG

A

higher affinity; plasma cells more long-lived; produced after chromosomal
splicing and class switching in IgM-producing B cells

MICR 2420 (1 decks)

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