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PID > Lecture 1: Basic Principles > Flashcards

Lecture 1: Basic Principles Flashcards

1
Q

Prokaryote Characteristics (6)

A
  • single circular DNA
  • no Nuclear Membrane
  • no Mitochondria
  • no golgi bodies
  • no ER
  • has complex cell wall
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2
Q

Examples of prokaryotes

A
  • bacteria

- blue green algae

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3
Q

examples of eukaryotes

A
  • animals
  • plants
  • fungi
  • protozoa
  • algae
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4
Q

Eukaryote characteristics

A
  • diploid genome
  • organelles
  • membrane-bound nucleus
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5
Q

methods to classify bacteria (5)

A
  • growth characteristics
  • cell morphology
  • gram stain characteristics
  • external structures
  • spore formation
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6
Q

examples of growth characteristics (9)

A
  • color
  • size
  • shape
  • smell
  • nutrients
  • antibiotic resistance
  • fermenation
  • hemolytic properties
  • lipid hydrolysis
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7
Q

Cell morphology examples (6)

A
  • coccus
  • bacillus
  • spirillum
  • fusiform bacillus
  • vibrio
  • spirochete
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8
Q

Gram stain procedure

A
  1. crystal violet
  2. iodine
  3. alcohol wash
  4. safranin
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9
Q

characteristics of Gram (+) cells

A
  • thick peptidoglycan layer with teichoic and lipoteichoic acids
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10
Q

characteristics of Gram (-) cells

A
  • thin peptidoglycan layer and outer membrane with LPS, phospholipids, and proteins
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11
Q

What is a techoic acid?

A

a water-soluble polymer of repeating ribitol phosphate units

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12
Q

what is a lipiteichoic acid?

A

a polymer with a fatty acid that is anchored in cytoplasmic membrane by diacylglycerol

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13
Q

what can techoic and lipoteichoic acids do?

A
  • distinguish bacterial serotypes and promote adherence

- can be virulence factors

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14
Q

Components of the gram (-) cell wall

A
  • outer membrane
  • periplasmic space
  • no teichoic acids
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15
Q

function and components of the gram (-) cell outer membrane

A
  • maintains structure, permeability barrier
  • provides protection from adverse environmental conditions, such as digestive system
  • phospholipid inner leaf
  • lipopolysaccharide
  • outer leaf
  • porins
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16
Q

what is LPS, and how does it affect the body?

A

lipopolysaccharide
- endotoxin that stimulates immune response–> shed into media and host, activates B cells and macrophages, induces macrophages and dendritic cells to release IL1, IL6, TNF, which induces fever and causes shock

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17
Q

what are the purpose of porins

A

porins allow diffusion of hydrophilic molecules <700Da, allows passage of metabolites and small hydrophilic antiobiotics

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18
Q

3 structural components of LPS

A

O antigen

  • linear polysaccharide
  • 50-100 repeating sugar units
  • differs between serotypes

core polysaccharide

  • branched, 9-12 sugars
  • contains phosphorylated KDO
  • essential for bacterial viability
  • same for each species

Lipid A

  • **endotoxin
  • phosphorylated glucosamine disacchardie with fatty acids
  • phosphates connect LPS units into aggregates
  • Essential for bacterial viability
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19
Q

what is KDO and what does it do?

A

1-deoxy-D-manno-oct-2-ulosonic acid

used by bacteria in synthesis of lipopolysaccharides

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20
Q

examples of external structures for bacteria

A
  • capsules
  • Flagella
  • fimbriae
  • spore formation
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21
Q

What is a capsule?

A
  • composed of polysaccharide or protein layers
  • its a “slime layer”, loosely adherent and non-uniform
  • aka glycocalyx
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22
Q

what kind of capsule does Bacillus anthracis have?

A

polypeptide capsule

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23
Q

what properties of a capsule allow it to help bacteria persist in their host?

A
  • poorly antigenic
  • antiphagocytic
  • major virulence factor
  • barrier against abx and host defense
    adherence
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24
Q

properties and uses of flagella

A
  • essentially propellers, though not all are motile
  • coiled flagellin protein subunits
  • anchored in membrane through hook and basal body
  • important in motility (chemotaxis)
  • -> swim straight then tumble, depending on which way flagellum spins
  • antigenic and strain determinants
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25
Q

physical characteristics of fimbriae (4)

A
  • aka pili
  • hairlike structures
  • composed of pilin protein subunits
  • not coiled
  • several hundred over entire surface of bacterium
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26
Q

how do fimbriae help the bacteria persist in the host

A
  • adherence
  • virulence factor for colonization and infection
  • DNA transfer via f pili
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27
Q

what is the f pili and what is it used for?

A
  • the sex pili
  • a tube that binds to other bacteria to transfer bacterial DNA
  • -> allows plasmids or chromosomes to jump into the new bacterium
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28
Q

unique product of corynebacterium and nocardia ?

A
  • mycolic acid lipids
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29
Q

unique characteristics of mycoplasma

A
  • no peptidoglycan, incorporates steroids from host into membrane
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30
Q

unique characteristics of mycobacteria

A
  • peptidoglycan layer intertwined with an arabinogalactan polymer, surrounded by wax-like lipid coat of mycolic acids
  • acid-fast stain
  • viruence and antiphagocytic
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31
Q

name two bacteria that utilize spore formation

A
  • bacillus

- clostridium

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32
Q

what do spores enable bacteria to do?

A
  • convert from vegetative to dormant state under harsh environmental conditions
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33
Q

what do spores contain?

A
  • chromosome
  • minimum proteins and ribosomes
  • calcium bound to dipicolinic acid
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34
Q

how are spores formed?

A
  1. spore septum begins to isolate newly replicated DNA and a small portion of cytoplasm
  2. paslma membrane starts to surround DNA, cytoplasm, and membrane isolated in step 1
  3. spore septum surrounds isolated portion forming the forespore
  4. peptidoglycan layer forms between membranes
  5. spore coat forms
  6. endospore is freed from the cell.
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35
Q

overview of spore formation

A

DNA replication, spore septum begins to isolate new DNA, plasma membrane forms, peptidoglycan layer forms between membranes, spore coat forms, endospore released from cell

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36
Q

overview of bacterial genetics

A

haploid chromosome
- one chromosome, one copy of each gene

plasmids
- extrachromosomal genetic elements

bacteriophages
- bacterial viruses (?)

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37
Q

Central Dogma of Genetics

A

DNA –> mRNA –> protein

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38
Q

Genetic mutations

A
  • silent
  • missense
  • nonsense
  • insertion
  • deletion
  • null
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39
Q

What changes will a silent mutation have

A

no change

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40
Q

what changes will a missense mutation have?

A

substitution of a different amino acid –> may or may not have an effect

silent to severe effect

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41
Q

what changes will a nonsense mutation have?

A

a premature stop –> non-functional protein

almost always severe effect

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42
Q

what changes will an insertion mutation have?

A

frameshift –> amino acids after shift are affected

usually severe since protein is typically nonfunctional

43
Q

what changes will a deletion mutation have?

A

frameshift –> amino acids after shift are affected

usually severe since protein is typically nonfunctional

44
Q

what changes will a null mutation have?

A

complete destruction of protein function through extensive insertion, deletion, or rearrangement

45
Q

types of genetic repair

A
  • direct DNA repair
  • excision repair
  • recombinational repair
  • SOS response
  • Error-prone repair
46
Q

how does direct DNA repair work?

A

enzymatic removal of damage

47
Q

how does excision repair work?

A

excision of damage, followed by synthesis of new DNA strand

48
Q

how does recombinational repair work?

A

retrieval of missing info by genetic recombination when both DNA strands are damaged

49
Q

how does the SOS response work?

A

induction of ~15 genes after DNA damage or interruption of replication

50
Q

how does the error-prone repair work?

A

last resort

  • fills in gaps with random sequences when DNA template is not available for accurate repair
51
Q

types of bacterial genetic transfer

A
  • transformation
  • transduction
  • conjugation
  • transposition
52
Q

what is transformation?

A

take up fragments of naked DNA and incorporate into their genome

donor cell undergoes cell lysis –> release of DNA fragments –> DNA enters recipient cell and integrates into DNA

53
Q

what is transduction

A

transfer from one bacteria to another by bacteriophage

transducing phage containing donor genomic DNA undergoes cell lysis –> release of phages –> phage infects recipient cell; donor DNA integrates into recipient DNA

54
Q

what is conjugation

A

quasi-sexual exchange of DNA

free plasmid moves from donor to recipient cell via sex (f) pilus –> integrated plasmid (episome) promotes transfer of genomic DNA, which integrates into recipient DNA

55
Q

what is transposition

A

“jumping” of DNA elements between DNA molecules

transposed DNA from the donor jumps into the sequence of the recipient

56
Q

What makes a virus a virus? (11)

A
  • filterable
  • obligate intracellular parasite
  • cannot make energy or proteins independently
  • RNA or DNA
  • naked capsid or envelope
  • components are assembled in order to construct the virus
  • viruses are NOT “alive”
  • must be infectious to endure
  • must be able to use host cell processes
  • must encode anything not provided by cell
  • must have self-assembling components
57
Q

what is an orphan virus?

A

one that does not have an associated disease

ex: reovirus is a virus of either the respiratory or enteric systems that does not have an associated disease.

58
Q

Viral classification overview

A

no consistent classification system

  • DNA or RNA genome
  • has been based off of viral characteristics
  • has been based on the tissue affected or disease produced
  • has been based off of the geographic location it was found in
  • has been based on virus characteristics
59
Q

What is the Baltimore System of viral classification

A

the most consistent and current classification; is by

- physical and biochemical characteristics (size, morphology, type of genome, means of replication

60
Q

T/F viruses are the same size.

A

False

Viruses can be different sizes

61
Q

Types of genetic material in viruses

A

DNA genome
- single or double stranded

RNA genome
- + or - sense, or ambisense (both)

MAY BE SEGMENTED)

62
Q

T/F the outer layer of a virus can be a capsid or an envelope.

A

true

63
Q

T/F the capsid is obtained by the host and the envelope is encoded by the virus

A

false

capsid is encoded by the virus

envelope is obtained by the host

64
Q

what functions do glycoproteins serve for viruses?

A

viral attachment and entry

fusion, enzyme functions (neuraminidase), immune response

65
Q

structure and capability of a naked capsid virus (8)

A
  • composed of protein
  • environmentally stable
  • released by cell lysis
  • spread easily by fomites, P2P, dust, droplets
  • retains infectivity when dry
  • survives gut
  • resistant to detergents
  • antibody response may be sufficient for immunoprotection
66
Q

structure and capability of a naked capsid virus (8)

A
  • composed of protein, lipid, glycoprotein
  • environmentally labile
  • released by budding or lysis
  • spread by large droplets, secretions, organs, blood
  • must stay wet to endure
  • cannot survive gut
  • detergents destroy infectivity
  • antibody and cell-mediated immune response, inflammation, hypersensitivity
67
Q

T/F all RNA-viruses are enveloped

A

true

68
Q

what can the envelope of a virus be composed of?

A
  • host membrane
  • viral proteins
  • viral glycoproteins
69
Q

what is tegument?

A

the space between the capsid and envelope, it contains enzymes, proteins, and mRNA

70
Q

viral replication of a naked capsid virus

A
  1. recognition
  2. attachment.
  3. penetration/entry
  4. uncoating
  5. macromolecular synthesis
  6. assembly
  7. release
71
Q

viral replicatoin of an enveloped virus

A
  1. recognition
  2. attachment
  3. penetration/entry
    4/ uncoating
  4. macromolecular synthesis
  5. assembly
  6. budding
  7. release
72
Q

in terms of viral replication, where do enveloped and naked viruses differ?

A

enveloped viruses require budding before release (this is where they integrate the host’s membrane into their structure). naked viruses do not need to undergo budding before release.

73
Q

In viral replication, what occurs during recognition?

A

viral attachment proteins (VAPs) identify specific host cells

74
Q

In viral replication, what occurs during attachment?

A
  • VAPs bind to cell receptors
  • receptors can be proteins or carbohydrates
  • determines host range and tissue tropism
75
Q

In viral replication, what occurs during penetration/entry?

A
  • non-enveloped viruses enter by receptor-mediated endocytosis
  • enveloped viruses enter by fusion of viral and cellular membranes
76
Q

In viral replication, what occurs during uncoating?

A
  • capsid/envelope is removed

- DNA delivered to nucleus, RNA to cytoplasm

77
Q

In viral replication, what occurs during macromolecular synthesis?

A
  • synthesis of viral mRNA
  • most DNA viruses use cell RNA polymerase II
  • most RNA viruses encode enzymes for transcription and replication
  • all viruses depend on host ribosomes, tRNA, and post-translational mechanisms
78
Q

In viral replication, what occurs during assembly?

A
  • 3D interlocking self-assembling puzzle
  • DNA in nucleus
  • RNA and pox in cytoplasm
79
Q

In viral replication, what occurs during budding?

A
  • occurs in enveloped viruses only!
  • viral glycoproteins delivered to cell membranes
  • capsid interacts with glycoprotein-membrane and surrounds capsid
  • budding occurs from plasma membrane, ER, golgi, or nuclear membrane
80
Q

In viral replication, what occurs during release?

A
  • lysis–> naked capsids usually lyse cell for release
  • budding–> most enveloped viruses release from membrane WITHOUT killing cell
  • exocytosis–> viruses that bud into cytoplasm remain cell-associated and released by exocytosis or lysis or nuclear membrane
81
Q

T/F viral mutations occur constantly.

A

true

82
Q

T/F RNA viruses have a lower mutation rate than DNA viruses

A

false

83
Q

Why do RNA viruses have a higher mutation rate than DNA viruses?

A

RNA viruses have no proof-reading capability

84
Q

Types of viral mutations

A
  • lethal
  • deletion
  • plaque mutants
  • host range mutants
  • attenuated mutants
  • conditional mutants
85
Q

what is a lethal mutation?

A

virus cannot replicated and dies without replicating

86
Q

what is a deletion mutation?

A

loss or selective removal of function

87
Q

what is a plaque mutant

A

a viral mutation that differs from wild type

88
Q

what is a host range mutant

A

a viral mutation that differs in target tissue or the species infected

89
Q

What is an attenuated mutant

A

a viral mutation that causes less serious disease

90
Q

what is a conditional mutant

A

a mutation that allows virus production only under certain conditions (temperature sensitivity for example)

91
Q

viral recovery genetic processes

A
  • recombination
  • integration
  • reassortment
  • complementation
  • marker rescue
  • pseudotype virus
92
Q

viral recombination

A

occurs readily between related viruses; exchange of genetic sequences

93
Q

viral integration

A

retroviruses and some tumorigenic viruses integrate into host genome; causes mutation of host

94
Q

viral reassortment

A

segmented viruses exchange segments when >1 strain infects a cell

95
Q

viral complementation

A

replication of a virus or expression of gene provides missing function in defective virus

96
Q

viral marker rescue

A

repair of a mutation with wild type sequence

97
Q

viral pseudotype virus

A

proteins/capsid from one virus and genome of different virus

98
Q

T/F recombination (both homologous and nonhomologous) only occurs in bacteria

A

false;

homologous and nonhomologous recombination can occur in both bacteria and viruses

99
Q

T/F we can utilize genetic engineering to engineer bacteria to help humankind.

A

True

ex: E. coli can produce insulin; there are yeast that present hepatitis B surface proteins for use in vaccines

100
Q

T/F animals, insects, humans, birds, the environment, etc. are all separate

A

False

all are connected through the ecosystem

101
Q

What is the One Health Initiative?

A

a coordinated effort between the AMA, AVMA, American Society of Tropical Med, CDC, USDA, US National Environmental Health Association, scientists, physicians, vets, acknowledging that human health, animal health, and ecosystem health are inextricably linked.

102
Q

Why did we see such a decrease in the more prominent diseases in the 70s and 80s?

A

vaccine development and changes in attitude toward vaccine use

increased use –> increased herd immunity

103
Q

why was there a slight uptick in TB cases?

A

drug resistance and immunocompromised hosts (HIV/AIDS victims)

104
Q

Why are some vaccination protocols working and some aren’t?

A

high variety of serotypes?

PID (10 decks)

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