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HLTH 2004 > Midterm 1 > Flashcards

Midterm 1 Flashcards

1
Q

Define microbiology

A

The study of microscopic organisms, those being unicellular, multicellular, or acellular

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2
Q

Define infection

A

The invasion and sustained colonization of microorganisms into locations in the body where they are not expected to be
Something atypical must occur for an infection to occur

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3
Q

What occurs in the host microbe relationship at birth?

A

Humans are free of microbes in utero
At birth, exposed to microbes which start to colonize in infants intestine by breathing then feeding
Start to establish a symbiotic relationship

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4
Q

How does the human-microbe relationship differ from person to person?

A

Some people have bacteria in their body at all times that are pathogenic to other people

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5
Q

What is your normal flora?

A

The microbes that establish residency in mucosa membranes open to the environment throughout life time

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6
Q

Define resident and transient flora

A

Resident: remain part throughout persons lifespan
Transient: only remain for a few hours, days, or months before they vanish

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7
Q

Give and define the four types of symbiosis.

A

Mutualism: both benefit from the interaction
Commensalism: one benefits, other is neither harmed nor helped
Parasitism: one benefits while the other is harmed or killed
Amensalisme: one can hamper of prevent the growth/survival of another without being affected by the other organism

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8
Q

Give an example for each of the 4 types of symbiosis

A

Mutualism: normal gut flora such as E. coli
Commensalism: bacteria that live in ear canal
Parasitism: bacterial infection (pathogens)
Amensalisme: pencicllium

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9
Q

What is a pathogen?

A

A microorganism capable of causing disease

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10
Q

What are opportunistic pathogens?

A

Microbes of the normal flora become opportunistic pathogens when balance is the normal flora and human host is interrupted
Do not cause disease in their normal habitat in a health person
Require something out of the norm to occur
Generally not the worst infections

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11
Q

What causes microbes to become opportunistic pathogens?

A

Compromised immune system: acute and chronic disease, malnutrition, stress, age, radiation/chemotherapy, immunosuppressive drugs
Changes in the normal flora
Entrance of the normal flora into areas of the body where it is not present under normal conditions

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12
Q

Define infectious disease

A

When an infectious agen causes pathological changes and disrupts normal physiological function

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13
Q

Define virulence and pathogenicity

A

Virulence: the degree of pathogenicity or disease prevailing power of a specific microbe
Pathogenicity: ability to become pathogenic
- related to the number of microorganisms, portal of entry, host defence, intrinsic characteristics of organism, and virulence factors

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14
Q

What are the common virulence factors?

A 
Adhesion (specific or nonspecific)
Colonization 
Invasion
Evasion of hosts défenses
Production of toxins
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15
Q

Describe adhesion

A

Most crucial step
Without adhesion, organism will be removed by ciliary motion, sneezing, coughing, swallowing, urine flow, tears, intestinal peristalsis
Must bing to host cell by pili or specific membrane receptor sites
May be specific or nonspecific

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16
Q

What is nonspecific adhesion?

A

Through nonspecific attractive forces or interactions

Hydrophobic, electrostatic, atomic and molecular vibrations, recruitment and trapping by biofilms

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17
Q

Describe colonization

A

The formation of a compact population by the infectious species
Usually colonize in tissues that are in contact with the external environment
Ex. Urogénital tract, digestive tract, respiratory tract, conjunctiva

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18
Q

Describe invasion

A

The process of entering new areas in the body (breaking down barriers)
May be aided by the production of extracellular substances: disrupt host cell membrane, break down primary and secondary barriers of the host, are called invasions
Dead cells in immediate vaccinate provide nutrients

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19
Q

How do viruses evade the hosts défenses?

A

Avoid contact with phagocytes
Inhibition of phagocytes engulfment
Survival inside the phagocytes
Production of products that kill or damage phagocytes before or after ingestion

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20
Q

What are exogenous and endogenous portals of entry?

A

Exogenous: from outside the body, in the environment
Endogenous: organism is already in the bod

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21
Q

What are the portals of entry?

A

Generally the same areas that support normal flora: skin, GI tract, mucous membranes, placenta
Majority have preferred portal of entry
If wrong portal, infection will not occur
Some enter via more than one portal ex. Streptococcus and staphylococcus

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22
Q

What portals of entry are present in the mucous membranes?

A

GI tract: pathogens present in food, liquid, and other ingested substances
Respiratory tract: pathogens enter through air, via dust particles, moisture and respiratory droplets from infected
Urogénital tract: usually contracted by sexual contact
Conjunctiva: eye

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23
Q

What is the parenteral route?

A

Means of bypassing other portals of entry
Pathogens are directly introduced to the subcutaneous tissue
Cuts, bites, stab wounds, deep abrasions, surgery

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24
Q

What are toxigenic organisms?

A

Produce toxins which are the underlying mechanism by which micro organisms produce disease
Can be enzymes, exotoxins, or endotoxins

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25
What are exotoxins?
Protein released by bacterium during exponential growth phase Can act at sites other than the location of infection Toxins produced are often species specific and associated with a particular disease
26
What are endotoxins?
Lipopolysaccharides of gram-negative cell wall Release during lysis initiated by effective host défense or by action of antibiotics Can act on sites remote from the original site of infection Less potent and less specific
27
Describe the diphtheria toxin
Discovered in 1871 Single protein comprised of two peptide chains (A and B) B binds to a receptor and helps the protein enter the cell A inhibits protein synthesis by binding elongation factor 2 EF2, causing cells to die Body tries to divide and kill cells at the same time Lymphnodes swell up causing thick neck with white rash known as grout
28
Define étiologie
The study of the cause of disease
29
What are Koch's postulates?
1. The suspected pathogen must be present in every case of the disease 2. The pathogen must be isolated from the diseased host and grown in pure culture 3. The pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible experimental host 4. The same pathogen must be isolated from the experimental host and must be shown to be identical to the original pathogen
30
What are some exceptions to koch's postulates?
Some pathogens cannot be cultured in the lab Many infectious diseases can be caused by several different pathogens A particular pathogen can cause different diseases - depending on the portal of entry Some diseases are caused by combinations of pathogens
31
Define epidemiology
Study of the patterns, causes, and effects of health and disease conditions in defined populations Three basic approaches: descriptive, analytical, and experimental
32
What is the miasma theory?
Diseases such as cholera and the plague were caused by pollution Prevalent belief before John snow
33
Describe descriptive epidemiology
Collecting and tabulating data concerning the disease Time course and chain of transmission important Includes information on the affected individuals, the location , and the period of disease occurance
34
Describe analytical epidemiology
Attempts to demonstrate a cause and effect relationship | Uses analysis all data collects in descriptive epidemiology
35
What are the disease categories?
Endemic: repeatedly present in a given population or geographic area Sporadic: breaks out only occasionally Epidemic: occurs with greater frequency than usual in a population in a given area Pandemic: worldwide epidemic
36
What are the body's two immune response mechanisms?
Innate (nonspecific) immune responses | Adaptive (specific) immune response
37
Describe your innate immunity
Protection by skin and mucous membranes Phagocytize cells (remove debris - macrophages, neutrophils, monocytes) Natural killer cells: lymphocytes that kill virally infected cells and tumours Complement system
38
What are the 5 different types of white blood cells?
``` Neutrophils: kill bacteria Eosinophils: allergic response, parasite killing Basophils: allergic reaction Monocytes: become macrophages Lymphocytes: direct immune system ```
39
What are the two types of lymphocytes?
T-cell: natural killer cells, helper cells (CD4+), cytotoxic cells (Cd8+) B-cells: bone marrow derived
40
What are the two components of the adaptive immunity?
Humoral: b-cells create plasma cells which form antibodies Cellular: helper cells and cytotoxic cells
41
What is antigen?
Any substance when introduced into the body stimulates the production of an antibody A pathogen is an antigen which causes disease
42
What is an epitope?
The smallest part of an antigen that can bind with an antibody
43
Describe antibodies
Proteins - immunoglobulins (Ig) In circulation and specific receptors on B cells Produced by ab-lymphocytes Recognize and bind to foreign antigens, forming antigen-antibody complex
44
Describe the structure of antibodies
Y shaped structures with two heavy chains and two light chains with specific antigen binding sites what are variable while the rest is constant
45
What are the different classes of antibodies?
IgA: major in circulation, can cross placenta IgA: in sécrétions, provide local protection IgM: largest of immunoglobulins, first activity in immune response
46
Describe cellular medicated immunity
Via t-cells Cytotoxic cells kill directly Helper cells activate macrophages and B-cell C-cells have direct surface receptors Tcells don't and must have antigen presented to them
47
What are the bodies three lines of défense?
1. Physical and chemical barriers: skin, mucous membranes, ciliary escalator, sweat, pH, lysozymes present in secretions 2. Phagocytosis, inflammation, fever, production of interferons/cytokines, activation of complement system 3. Specific or adaptive défenses
48
What are the functions of the plasma proteins?
Structural support Transport of molecules across the membrane; pumps, cotransporters, and channels Enzyme regulators to control chemical reactions Receptors for hormones and other regulatory substances Surface antigens
49
Describe gram positive
Thick peotidoglycan layer outside plasma membrane Contains trichroic acid and lipoteichioc acid Minimal periplamic space between plasma membrane and cell wall
50
Describe gram negative
Thin peptidoglycan layer Outer membrane that provides cover and is anchored to the lipoprotein molecules of the peptidoglycan layer Outer membrane is similar to the plasma membrane Large periplasmic space
51
What is peptidoglycan?
A polymer comprised of various sugars and amino acids that forms a crystal lattice Absorbs crystal violer stain Peptide cross bridge and side chain with carbohydrate backbone mad dog n-avetylglucosamine and n-acetylmuramic acid
52
What is bacterial flagella?
Long helical filament about 12 to 30nm in diameter Used for movement in the environment Protein components are flagellons assembled to form a cylindrical structure with a hollow core Hook anchors filament anchored by basal body which consists of rod and two pairs of discs
53
What are the different types of bacterial flagella?
Monotrichous: single polar structure at one end Amphitrichous: single polar structure at each end Lophotrichous: flagella in rifts at one or both ends Peritrichous: flagella distributed over the general surface
54
What are the two patterns of bacterial mobility?
Runs and tumbles
55
What are some other surface appendages?
Pili (fimbrae): more rigid than flagella, composed of pilin proteins Cilia: prokaryotes, nearly identical to flagella but shorter Microvilli: membrane extension on surface of eukaryotic cells used for absorption
56
What are the three types of genetic transfer in bacteria?
Transformation: genetic alteration of a cell through the direct uptake and incorporation of foreign DNA Transduction: transfer of DNA from one bacteria to another through a bacteriophage Conjugation: the transfer of genetic material via cell-to-cell contact by forming pillus
57
Describe biofilms
Collection is surface associated microbes enclosed by extracellular, mostly polysaccharide matrix Can include non cellular material First colony adheres and anchors permanently if not removed Form pseudotissue structure
58
Describe the different shapes
``` Coccus: round Bacillus: rod Vibrio: filament Spirilla: spiral Pleiomorphic: bunch of different shapes Spirochète: loose spiral Diplô: pair Staph: cluster Strep: chain Palisades: layers Tétrad: 4 ```
59
Describe the phases of a population growth curve
Lag phase: bacteria have adapt to medium, metabolically active Logarithmic or exponential growth phase: the rate of growth increases with time, each subsequent binary fission doubles the bacterial cells Stationary phase: occurs when essential nutrients are depleted or byproducts of metabolism accumulate Death phase: begins when growth stops and number of dead cells is larger then viable
60
How do you measure the optical density?
Small sample taken from flask is placed in cuvette choose a wavelength that is absorbed by that bacteria
61
What are some different measurements of cell mass?
Dry weight: estimation, time consuming, cells need to be washed then dried Turbidity: measured with spectrophotometer in O.D units, greater cell mass, the less light will pass through, fast, does not account for dead cells
62
What are some different measurements of cell number?
Direct cell count: microscopically in counting chambers Viable counts: only viable cells are counted - pour playing - spread plating - most probable number method
63
What factors influence bacterial growth?
Nutritional requirements (carbon, nitrogen, sulfur, phosphorus, minerals) Température Osmotic pressure Other atmospheric conditions
64
What are mesophiles and Thermophiles?
Mesophiles: optimal growth in moderate temperatures, live in soil, human body, animals Thermophiles: heat loving organisms, grow best at temperatures of 45 or higher, hot springs, Dead Sea hydrothermal vents, tropical soil composts, hay stacks
65
What are paychrophiles and psychrotrophs?
Psychrophiles: cold living, can grow at 0 or less but optimal around 15 Psychrotrophs: grow very slowly at 0 but have range to 25-30, abundant in nature and can cause food spoilage in refrigerator temperatures
66
What are osmophikes and halophiles?
Osmophiles: microbes that require high solute concentration in the environment for optimal growth Halophiles: salt lovers
67
Define barotolerant and barophiles
Barotolerent: microorganismes that can survive in increased hydrostatic pressures Barophiles: grow best under high hydrostatic pressure, occur in deepest part of oceans
68
What are microaerophiles and aerotolerant anaerobes?
Microaerophiles: require a low concentration of oxygen | Aerotolerant anaerobes: can grow in presence of oxygen but cannot use for energy requirements
69
Describe bergeys manual of systematic bacteriology
1923, berger and colleagues published first comprehensive classification of bacteria Used for both classification and identification of bacteria and archaea Later versions incorporated 16S ribosomal DNA, amino acid sequence, genetic sequences
70
Describe rickettsias and chlamydias
Very small gram negative bacteria Majority require host for replication Generally rod-shaped but also may look coccoidal Often cause disease Rickettsiae need a vertebrate and an arthropod host Chlamydias do not infect invertebrates Rivkettsiae rickettsii: Rocky Mountains spotted fever Chlamydiae trachomatis: urigenital infections
71
What is mechanism of action?
Specific biochemical mechanisms underlying pathway inhibition or disruption of natural physiological processes leading to stasis or cell death
72
What are the ins of pharmacology basics?
Administration: digestive or parenterally Absorption: rate at which drug leaves the site of administration and appears at site of action Distribution: relative distribution in body compartments
73
What are the outs of pharmacology basics?
Biotransformation: metabolism of drugs - phase 1: conversion of ionized molecules - phase 2: new compounds/moieties are introduced to drug Clearance: primarily via renal system
74
What is the therapeutic index?
``` System to correlate dosage with therapeutic effect and risk of toxicity TI = LD50/ED50 LD: lethal dose ED: effective dose Higher value means safer ```
75
Describe a time response curve
``` Onset of time response Cessation of drug effect Peak effect time Duration of action time Latency of effect time Threshold level - T1 ```
76
What are the different ways antibiotics work?
Disruption of cell membrane Disruption of cell wall synthesis Disruption of nucleic acid synthesis Disruption of RNA synthesis Disruption of protein synthesis: targets 30S and 50S subunits Disruption of metabolic production folic acid metabolism
77
Describe 16s ribosomal profiling
Part of 30s subunit 16s has several highly conserved regions and a highly variable region Universal primers are used to amplify the gene using PCR Séquenced and compared to sequences in various databanks Hybridiez to proprietary library of probes
78
What is ROS?
Reactive oxygen species | - cause damage to your system
79
What is PCR?
Polymerase chain reaction - heat up DNA causing strands to separate - pruners bind to target DNA sequences - tacPolymerase binds and adds nucleotides - occurs over and over to make additional copies
80
What is a virus?
Microscopic particles that infect other organisms and can only replicate within a host cell Contain rna or DNA surrounded by capsid Hijacks the biochemical machinery of the host
81
What are the steps to the life cycle of mammalian viruses?
1. Attachment 2. Entry 3. Replication 4. Biosynthesis 5. Assembly 6. Release
82
Describe the capsid
Subunits called protomeres assembled into capsomeres which aggregate to form capsid Morphological distinction: helical, icosahedral, or complex Some have envelope outside capsid
83
What is the nucleocapsid? Spikes?
The interface between viral DNA and capsid | Spikes are glycoproteins which form long projections from nucleocapsid or envelope
84
What is a virion?
A fully assembled viral particle
85
Describe enveloped viruses
Might include some viral glycoproteins Some or all host membrane proteins are replaced by viral proteins Hemaggglutinin: antigenic glycoproteins that helps virus bind to target cell Neuradinase: cleaves sialic acid groups from host glycoproteins to encourage release from the cell
86
What is tamiflu?
Prevents virion from being released from the cell Stays attached to membrane forever Blocks action of influenza type A and B Given to people with a high risk of complications from the flu
87
What are the steps in multiplication of naked animal viruses?
1. Adsorption 2. Penetration 3. Uncoating 4. Production of mRNA from viral DNA 5. Replication of viral DNA and production of some viral proteins 6. Production of capsid proteins 7. Maturation and assembly 8. Release
88
What are the steps for multiplication of enveloped animal viruses?
1. Adsorption 2. Penetration by endocytosis 3. Uncoating of envelope and capsid 4. Replication of viral DNA 5. Production of capsid protein 6. Release
89
What are abortive infections?
Occur in non-permissive cell, no virus produced | Ex. Flu from respiratory tract found in liver
90
What are persistent infections?
Generally do not cause cell death Often production is negligible, slow, sporadic, or very localized Produce very slowly, not stealing all the nutrients and keeping host alive as long as possible
91
What are chronic viral infections?
Limited production, lyric | Ex. HIV
92
What are latent chronic infection?
Persist in latent phase (no or minimal production) | Ex. TB
93
What are slow viral infections?
Prolonged incubation, significant physiological/morphological changes in host cell
94
What are transforming viral infections?
Insert DNA in genome and can remain there indefinitely | In almost all cases, cell will change general structure
95
What are some outcomes of viral infections?
Host cells may experience morphological, physiological, biochemical, and genotoxic damage
96
What is the Baltimore system based on?
Places the viruses in to one of seven groups based on how genetic info is converted to mRNA
97
What groups in the Baltimore system are DNA, RNA, or reverse transcriptase viruses?
DNA: I, II, VII RNA: III, IV, and V Reverse transcripase: VI and VII
98
Describe DNA viruses
Transcription usually occurs in the nucleus using host polymerases Host machinery recognizes sequences Replication begins at origin and relies on DNA-dependent DNA polymerase
99
Describe RNA viruses
May be an mRNA strand (positive strand) or as a template for mRNA RNA virus must code for RNA dependent replicates and transcriptases because we do not replicate or transcribe from RNA Positive sense can be directly translated by host ribosomes
100
How does replication of a negative strand RNA virus occur?
(-) parental RNA becomes mRNA (+) using transcription by viral RNA polymerase - translated to proteins using host enzymes and then assembled (-) parental RNA is transcribed to (+) RNA using RNA polymerase and then replicated into (-) genomic RNA and then assembled into progeny virus
101
What are the steps to the multiplication of bacteriophages?
``` Adsorption Penetration Replication Assembly Maturation Release ```
102
Describe penetration of a bacteriophage
Virus particle contents enter the host cell Mediated by highly sensitive recognition molecules Majority of the virion enters the host
103
Describe uncoating of a bacteriophage
Viral neucleic acid is released Process varies between viruses Enzymes within vacuoles or vesicles will dissolve envelope and capsid of the virus to release viral nucleic acid
104
Describe replication of bacteriophages
Metabolism shifts and protein synthesis to gene expression of the viral nucleic acid Results in production of viral components
105
What are the two methods of assembly and release of bacteriophages?
Budding and lysis
106
Describe assembly of a bacteriophage
Capsid is generally produced first as an empty check that serves as a container for the nucleic acid through encapsulation
107
Describe lytic phages
After multiplication they destroy the bacterium by lysis and newly formed phages are released into the environment Eclipse period: no infectious phages particles found in host cell Intracellular accumulation phase: assembly Lysis and release phase
108
What are HSC?
Haematapoeitic stem cells | Give rise to most types of blood cells
109
What is a local bacterial infection?
Producing HSC and branch off and become neutrophiles and lymphocytes in bone marrow at a steady rate Neutrophil matures and crosses into the bloodstream on its own
110
Describe systematic bacterial infections
Emergency myelopoiesus rapidly produces both immature and mature neutrophils in process known as neutrophilia (basically amplifies each step) Immature neutrophils enter the bloodstream early by pumping them into the blood stream as opposed to letting them pass through on their own Once in bloodstream, receive signals that cause them to become mature
111
Describe IRES
Internal ribosome entry site Occurs as a survival mechanism when cell shuts down other translation Can recruit without 5' cap
112
What is the point to IRES?
Allows translation of vital proteins to occur even when translation is blocked or shut down such as P53 and HSP/HST
113
What is functional genomics?
Field of molecular biology that describes investigations that focus on studying genes and their functions in a systematic manner
114
What is interaction analysis?
Put a bunch of hairpins upstream preventing translation Place ires in area between hairpin and start codon See expression of that gene if it uses ires structure Used to identify new genes involved in ires dependent translation
115
What does the 5' cap do?
Directs pre-mRNA to processing and transport pathways, regulate mRNA turnover
116
What is melting?
Unwinding into a single stranded piece

HLTH 2004 (3 decks)

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