Question

Looking for someone to kind of test me in Microbiology... I can send you the outline. I'm trying to get ready for a test

Answer 1

what is microbiology

Answer 2

im testing you

Answer 3

The study of microbes not seen by the visable eye

Answer 4

we are on specific chapters tho

Answer 5

double stranded DNA found in
inflenza virus
parovirus
polio virus
T4 virus

Answer 6

the test isn't cumulative

Answer 7

what r the topics?

Answer 8

antibiotics are mostly obtained from
bacteria
viruses
fungi
angiosperms

Answer 9

viruses.. host ranges, lytic nd lysogenic stages, flora, different transmissions, focal/local/systemic disease, adherence factors, fomites, endotoxins and exotoxins..

Answer 10

you asked about double stranded DNA and viruses. I do know that a viruses nucleic acids can be either Dna or Rna (retrovirus) therefore either double stranded or single

Answer 11

T4 infects---------bacterium

Answer 12

ok. I understand that a host usually stays in its host range which can be narrow or wide ranging. Bacteriaphage infect bacteria, etc

Answer 13

T4 infects---------bacterium
its E.coli

Answer 14

induction converts -----phage into ------phage

Answer 15

ok. an enteric. apart of the family enterics, gram neg rods

Answer 16

are you referring to the prophage?

Answer 17

im giving u blanks to fill them

Answer 18

I'll probably need help because the professor's outline and slides didn't go into induction

Answer 19

lysogenic phage or cycle into lytic cycle

Answer 20

this is induction

Answer 21

I didn't realize those were called induction. Ok, we are responsible for understanding both cycles

Answer 22

could you ask some questions from these cycles

Answer 23

http://quizlet.com/19911350/microbiology-exam-2-flash-cards/
i think these quize cards can help u alot

Answer 24

I have been just thinking about some of the differences between the two. Lytic cycle ends in host cell lysis. Lysogenic can "decide" to end in cell lysis or become "latent" just replicating along with the cell.

Answer 25

When a virus is capable of going into the lysogenic cycle can lead to chronic/persistent disease/infections like HIV, measles

Answer 26

We have to know acute, chronic, and latent disease

Answer 27

in the lysogenic cycle the DNA of the bacteriophage
joins the bacterial chromosomes
attaches to the inner surface of the host membrane
is immediately degraded when enters the host
goes directly to host ribosomes for translation

Answer 28

I wish I could send you the outline in like an email. It is difficult finding someone willing to test me right now

Answer 29

attachment, penetration, biosynthesis, maturation and assembly, release, right?

Answer 30

but im testing you and u have many concepts about ur test

Answer 31

u can send outline in reply

Answer 32

Virus latency (or viral latency) is the ability of a pathogenic virus to lie dormant (latent) within a cell, denoted as the lysogenic part of the viral life cycle. A latent viral infection is a type of persistent viral infection which is distinguished from a chronic viral infection

Answer 33

Chapter 13: Viruses



· General Characteristics:

Ø Obligate intracellular parasite

Ø Nucleic acid is either DNA or RNA

Ø Nucleic acid is covered by a protein coat

Ø Viral replication occurs inside host cell, utilizing host cell enzymes and replicating machinery

o See Table 13.1 to compare viruses with bacteria



· Host Ranges:

Ø Specific host type in which virus can infect

o Bacteria

§ Bacteriophage only infect bacteria

§ What is Phage Therapy?

o Animals

§ Small pox only infects humans

§ West Nile infects humans and a wide range of animals and birds

o Plants

§ Tobacco mosaic virus



· Viral Size and Morphology: (Fig. 13.1)

Ø Size range is between 20 to 14,000 nm

Ø Nucleic acid can be single or double stranded DNA or RNA (retro-virus)

Ø Capsid is comprised of capsomeres (subunits), which surrounds and protects the nucleic acid in the core

Ø Envelope, if present, is derived from the host cell plasma membrane, and surrounds the capsid

Ø Spikes are carbohydrate-protein complexes embedded in the envelope, and facilitate attachment to host cell





· Viral Shapes:

Ø Polyhedral (Fig. 13. 2 a)



Ø Helical (Fig. 13.4 a)



Ø Complex (Fig. 13.5 a)





· Viral Replication:

Ø Lytic Cycle: (Fig. 13.11)

o Attachment results from a chance collision between virus and host and non-covalent interactions between viral spikes and host cell receptors



o Penetration of host results from the action of virally produced lysozyme, and contraction of the tail sheath, which injects viral nucleic acid across the cell wall and membrane into the host cytoplasm



o Biosynthesis of new virus occurs after host DNA is degraded, then viral DNA is transcribed, and translated into viral components



o Maturation occurs with the spontaneous assembly of viral components into mature virus (virions)



o Release of the virions occurs when virally produced lysozyme degrades host cell wall (from the inside), resulting in host cell lysis

§ Host cell dies as an outcome of the Lytic cycle





Ø Lysogenic Cycle: (Fig. 13.12)

o Attachment and penetration same as in the Lytic cycle



o Viral DNA integrates into host cell chromosome as a prophage, and becomes latent (inactive)



o Prophage is replicated each time host DNA replicates



o Prophage may excise from host cell chromosome, and either enter the Lytic cycle, or reinsert as a prophage and return to latency



o Excision of the prophage may occur spontaneously or as a result from an environmental stressor such as UV exposure or certain chemicals



§ Why do people with Herpes simplex I sometimes experience outbreaks of fever blisters after sun exposure?



§ What is shingles?



§ Are the above examples of Lytic or Lysogenic viruses?

Ø Implications of Lysogeny:

o Lysogenic cells are immune from reinfection from the same phage type

§ Host may be infected by multiple different phage types



o Host cell may exhibit new characteristics (phage conversion)

§ An avirulent bacterium may become virulent

· V. cholerae and C. botulinum acquire their virulence through phage conversion.



o Specialized transduction (Fig. 13.13) may occur when the prophage excises, taking with it adjacent bacterial genes, and subsequently transferred to a new host bacterium.



Ø Animal Virus Multiplication: (pg. 385)

o Attachment involves the non covalent interactions between viral spikes and complimentary host cell receptors.

§ GP120 viral spikes found on HIV envelope attach to complimentary CD4 receptors found on human T-helper cells



o Penetration occurs by 2 mechanisms: (Fig. 13.15)

§ Pinocytosis

§ Fusion



o Uncoating is a result of virally produced enzymes that digest the capsid, releasing the nucleic acid into host cell cytoplasm



o Biosynthesis and assembly occurs when viral DNA is transcribed, and translated, resulting in the production and assembly of virions



o Release of non-enveloped viruses generally involves host cell lysis, compared to enveloped viruses, which release from host by budding (Fig. 13.20)



· Persistent Viral Infections (Fig. 13.21)

Ø Virus numbers increase and accumulate over time.

o Measles virus

o Rubella

o Hepatitis B

o Papillomavirus

o HIV



§ Antigenic Shift: (pgs. 374-375)

· As a result of gene shuffling a new phenotypic variant arises

o Swine flu

o Bird flu

o Human flu











Chapter 14: Principles of Disease and Epidemiology



· Definitions:

Ø Pathology is the study of disease



Ø Etiology is the study of the cause (agent) of disease



Ø Pathogenesis is how a disease develops



Ø Infection is the colonization of a host by a pathogen



Ø Disease is an altered state of health



Ø Normal flora (Fig. 14.1) (Table 14.1) are permanent bacterial residents (colonized), which generally do not cause disease under normal circumstances



Ø Transient flora is generally present for short periods of time, after which they disappear



o What is microbial antagonism?



o How is normal flora beneficial?



o What happens when normal flora is disrupted?



o How is normal flora disrupted?



· Host-Microbe relationships (Symbiosis) (Fig. 14.2)

Ø Commensalism is a relationship in which 1 partner benefits and the other is unaffected.

Ø Mutualism is a relationship in which both partners benefit.

Ø Parasitism is a relationship in which 1 partner is detrimental to the other. Examples are helminthes, viruses, and pathogenic bacteria.



o Can normal flora become pathogenic?



§ How?



§ What is an opportunistic pathogen?





· Factors that lead to opportunistic pathogenesis:

Ø Microbe becomes displaced from its “normal” region

o How?



Ø Host becomes immunocompromised

o How?







Ø Examples of opportunistic pathogens

o Neisseria meningitides

o Streptococcus pnuemoniae

o Candida albicans

o E. coli

o Clostridium dificile



· Koch’s postulates: (Fig. 14.3)

· Experimental process which demonstrates a direct cause and effect relationship between a particular agent and disease.



· Classifying infectious diseases:

Ø Signs are (objective changes) measurable and observable

o Examples



Ø Symptoms are (subjective changes) not measurable or observable

o Examples



Ø Syndrome is a combination of both signs and symptoms



Ø Communicable disease is spread from 1 host to another by direct or indirect modes of transmission

o TB, Herpes, Measles, HIV



Ø Contagious disease is spread easily

o Flu, Conjunctivitis, Impetigo



Ø Noncommunicable diseases are not spread from 1 host to another

o Legionella, Tetanus, Hanta virus



· Disease frequency:

Ø Incidence represents the number of new cases of a disease during a given time frame



Ø Prevalence represents the number of all cases of a disease during a given time period



Ø Sporadic diseases occur occasionally

o Food borne outbreaks



Ø Endemic diseases are constantly present in a population

o Common cold



Ø Epidemic disease occurs when many people develop a disease in a short period of time

o Influenza, AIDS



Ø Pandemic is a worldwide epidemic

o Influenza, AIDS







· Disease Duration:

Ø Acute disease exhibits a rapid onset with a short duration

o Influenza, food poisoning, bacterial meningitis



Ø Chronic disease develops slowly with a long duration or reoccurrence

o TB, Hepatitis B



Ø Latent disease the agent remains inactive for extended periods, with reoccurring periods of activity

o Shingles, Herpes I and II



· Classification of infections based on host involvement:

Ø Local is confined to a small area

o Boil

§ Caused by Staphylococcus aureus



§ Can local infections become systemic?



Ø Systemic involves multiple body systems and spreads through blood and lymph

o Septicemia



Ø Focal involves the agent entering at a location, and infects a different location

o Endocarditis



§ Why certain individuals should take antibiotics, prophylactically, prior to dental procedures?



§ Distinguish between bacteremia and septicemia?



Ø Primary infection occurs when a microbe causes an initial infection in a host

o Influenzae virus

o HIV



Ø Secondary infection follows primary infection, when host becomes immunocompromised as a result of the primary infection, and subsequently develops a separate infection



Ø Subclinical, also known as carrier state, exhibits no noticeable signs or symptoms of illness

o TB, Hepatitis A, HIV, Salmonella (Remember Typhoid Mary)



· The Stages of Disease (Fig. 14.5)



Ø Incubation period is the time following exposure to the first appearance of signs and symptoms. This period is variable depending on the microbe, infectious dose, virulence factors, and host immune status.



Ø Prodromal period follows incubation when patient generally exhibits mild symptoms

o Malaise and headache





Ø Illness period follows prodromal, with the expression of all characteristic signs and symptoms of disease

o Chills, fever, sore throat, vomiting, diarrhea, etc



Ø Decline period follows illness period, when signs and symptoms begin to diminish, however, the patient is vulnerable to secondary infections.



Ø Convalescence (recovery) period follows decline period, when the patient recovers and returns to pre-diseased state.



· The Spread of Infection:

Ø Reservoir of infections is the “naturally-occurring” source of the pathogen.

o Human

§ HIV, HBV, Herpes, Shigella



o Animal

§ Rabies, Hanta virus, Anthrax, Salmonella, West Nile virus



§ What are Zoonoses? (Table 14.2)



o Soil

§ Tetanus, Fungi, Anthrax, Botulism



o Water

§ Cholera, Salmonella, Shigella, Enteric bacteria and viruses



· Disease Transmission:

Ø Direct contact (person-to-person) (Fig. 14.6 a) requires physical contact between the source and the host.



o Guards against direct contact (Fig. 14.6 b) agents are generally barriers such as gloves, condoms, eyewear, and gowns.



Ø Indirect contact involves non-living objects (fomites) (Fig. 14.6 c)

o Needles, bedding, utensils, toys, money, diapers



Ø Droplet transmission (Fig. 14.6 d) occurs when respiratory droplets are discharged via sneezing, coughing, generally less than 1 meter.



o Name at least 1 disease/ or disease agent that transmits by:

§ Direct contact

§ Indirect contact

§ Droplet transmission



Ø Vehicle transmission (Fig 14.7 a-c) requires a medium such as, air, water, or food.

o Water borne transmission usually involves water contaminated with raw or inadequately treated sewage



o Food borne transmission usually involves fecal contamination, derived from unsanitary processing, improper cooking, inadequate hand washing and inadequate refrigeration.



o Airborne transmission occurs when a pathogen travels generally greater than 1 meter, usually respiratory pathogens.



Ø TB

Ø Fungi spores

Ø Bacterial spores

Ø Measles virus

Ø Staph and Strep sp.



Ø Vector transmission involves insects and arthropods such as mosquitoes, houseflies, fleas and ticks.

o Mechanical vector transmission occurs when the agent is transmitted on insects’ body parts.

§ House flies (Fig. 14.8)

· Fecal pathogens

o Shigella

o Salmonella

o Biological vector transmission (Table 14.3) occurs after agent reproduces in the vector, and transmits via a bite or defecation.

§ Lyme’s disease transmitted by deer tick

§ West Nile virus, and malaria transmitted by mosquito

§ Plague transmitted by rat flea





· Nosocomial Infection

Ø Hospital-Acquired

o Currently ranks number 8 on the leading causes of death in the US

o ~ 2 million case per year

o ~ 20,000 deaths

§ Predisposing Factors (Fig. 14.9)



o Microbial characteristics: (Table 14.4)





o Opportunistic and antibiotic resistant

§ MRSA, VISA, VRSA,VRE, MDRTB, Pseudomonas aeruginosa



o Patient’s immune status:

· Compromised by preexisting disease, chemotherapy, radiation therapy, trauma, malnutrition

· Primary barriers may be damaged due to burns, surgical incisions, bed sores











o Chain of Transmission:

· Principle routes are direct contact from staff to patient, patient to patient, and visitor to patient

· Indirect contact via fomites



o What fomites are commonly involved with hospital transmission?



Ø Control of nosocomial infections:

o More vigilant use of aseptic techniques such as frequent and thorough hand washing, disposable supplies, minimize invasive procedures

o Infection Control Nurse





Chapter 15: Microbial Mechanisms of Pathogenicity



· Pathogenicity is the ability of a pathogen to cause disease in a host



· Virulence is the degree of pathogenicity



· Portals of Entry: (Table 15.1)

Ø Mucous membranes:

o Respiratory access via inhalation of droplets

o Gastrointestinal access via contaminated food, water, and fingers

o Genitourinary access via sexual contact

o Conjunctiva access via droplets and splashes





Ø Intact skin is generally impenetrable by most microbes

o Exceptions are some helminthes

§ Schistosomes (pg. 674)



Ø Parenteral route occurs when microbes are deposited beneath the skin

o Injections, puncture wounds, bites, surgery and cuts.



· Number of invading pathogens:

Ø Lethal dose (LD50) is the dose of pathogens required to kill 50% of the test population



Ø Infectious dose (ID50) is the dose of pathogens required to cause infection in 50% of the test population



· Adherence Factors: (Figure 15.1)



Ø Adherence is accomplished by the interaction of microbe surface molecules (ligands), and complimentary host cell receptors.



Ø Fimbriae contain ligands that bind complimentary host cell receptors







Ø Capsules increase adherence and help prevent phagocytosis

o Biofilms

§ How do biofilms relate to pathogenesis?



Ø M protein is a cell wall component found in Streptococcus pyogenes

o Strongly electrically negative

§ Increases adherence

§ Antiphagocytic



· Toxic Enzymes:

Ø Coagulases produced mainly by Staphylococcus aureus, convert fibrinogen (soluble) into fibrin (insoluble).



Ø Kinases produced mainly by Streptococcus pyogenes and Staphylococcus aureus, dissolve fibrin



o How can kinase be used therapeutically?



Ø Hyaluronidase produced mainly by Staphylococcal, Streptococcal, and Clostridial species, dissolve hyaluronic acid (cellular adhesive)



Ø Collagenase produced mainly by Clostridial species, dissolves collagen, a protein found in a majority of tissues, such as muscle and nerve coverings, connective tissues and bone



· How pathogens damage host cells

Ø Direct damage may occur when a pathogen enters and exits a host cell



Ø Most damage occurs from the effects of toxins(Fig. 15.4) (Tables 15.2 and 15.3)

o Exotoxins

o Endotoxin



§ Exotoxins are proteins and enzymes, which, when released into the surroundings affect a host in a variety of ways.

§ A-B toxins (Fig. 15.5)

o Have an active and binding component

· Diphtheria toxin produced by Corynebacterium diptheriae enters host cell and inhibits protein synthesis.



· Botulinum toxin (neurotoxin) produced by Clostridium botulinum inhibits the release of acetylcholine (neurotransmitter) at the neuromuscular junction, resulting in “flaccid” paralysis.



· Tetanus toxin (tetanospasmin) produced by Clostridium tetani blocks the action of acetylcholinesterase (relaxation pathway), resulting in “tetanic” contractions.



· Cholera toxin produced by Vibrio cholerae is a heat-labile (heat sensitive) enterotoxin, and binds intestinal epithelial cells where it greatly increases permeability, producing “perfuse” watery diarrhea (3-5 gallons lost per day).

· Staphylococcal enterotoxin produced by Staphylococcus aureus is heat-stable and causes acute symptoms (1 to 6 hours after ingestion) of diarrhea, and vomiting. Usually self-limiting in healthy adult, but may be problematic with elderly and immunocompromised.



§ Endotoxin is a structural component of Gram negative bacterial cell walls.

· Lipopolysaccharide (LPS) molecule is composed of lipid A and polysaccharide O.

· Lipid A component acts as endotoxin when liberated from cell wall.

o How is this accomplished?



· Signs and symptoms are generalized chills, fever, headache, and hypotension and in severe cases shock.



· Pyrogenic Response: (Fig. 15.6)





· Endotoxic (Septic) shock

o In response to endotoxin, phagocytic cells release tumor necrosis factor (TNF), which causes an increase permeability of capillaries, resulting in sudden fluid loss, and subsequent hypotension.


Approximately 750,000 cases in the US per year, and approximately 50% die within 6 months.

Answer 34

scientific study of microorganisms and their effects on other organisms

mycology
virology
bacteriology
microbiology

Answer 35

it might be a little basic compared to what you know

Answer 36

Eukaryotes have a nucleus and membrane bound organelles Prokaryotes don't.

fungal organism
eukaryote
Pro No Nuc Yo DaNA
EUK Nuc w/ bORGs Pro No!

Answer 37

Study of protozoa

Parasitology
Protozoan
Protozoology
protozoa

Answer 38

i fully understand the outline now test urself by answering these mcqs.

Answer 39

before nucleus". Unicellular microorganisms that do not have nucleus or organelles BUT still has DNA strands, generally enclosed by peptidoglycan bacterial cell wall and reproduce by asexual binary fission

prokaryote
Prokaryotes
eukaryote
Eukaryotes

Answer 40

infectious PROTEIN that is resistant to most procedures that modify nucleic acids. Causes CJD

Protozoan
Virus
prion
molds

Answer 41

microbiology

Answer 42

Resistive infectious protein. Causes CJD

Prion
protozoa
Virus
Protozoan

Answer 43

Study of immunity

virology
microbiology
mycology
Immunology

Answer 44

no the prokaryotes don't have membrane bound organelles

Answer 45

Mycroplasma → Smallest of free-living bacteria w/ no cell wall.

True False

Answer 46

u r right

Answer 47

protozoology

Answer 48

prokaryotes-binary fission

Answer 49

virus-infectious proteins

Answer 50

Submicroscopic acellular obligate parasite with DNA or RNA, surrounded by capsid protein coat

Virus
viruses
molds
prio

Answer 51

Rickettsiology → bacterial obligate intracellular parasite - causes typhus fever via an insect vector

True False

Answer 52

cjd caused by a virus?

Answer 53

u r right good

Answer 54

immunology

Answer 55

submicroscopic, acellular, obligate intracellular parasites protected by a capsid protein coat that contain nucleic acid core (EITHER DNA or RNA)

yeasts
viruses
Virus
virology

Answer 56

mycoplasma.. atypical cell wall.. no cell wall so true.. can't use penicillin.. no peptidoglycan to attack

Answer 57

right again

Answer 58

Viruses are excluded from the "Big Tree" of Life because __b___
a) They are too small to be considered as living entities.

b) They have no ribosomes.

c) They only have a few lytic enzymes of their own.

d) They are obligate intracellular parasites.

Answer 59

virus- capsid (head) contains nucleic acids- 3 basic shapes- polyhedral, helical and complex.. complex has the capsid which is composed of capsomeres and have a sheath which can compress and contract to "inject" the dna during penetration

Answer 60

___a____ A group of ubiquitous free-living microorganisms that have:
(i) absorptive, phototrophic, or phagotrophic types of nutrition

(ii) cells in the size range of 5-150 um,

(iii) genetic material enclosed in a membrane.
a) Protists

b) Bacteria

c) Archaea

d) Yeast

Answer 61

true

Answer 62

they are obligate intracellular parasites

Answer 63

bacteria

Answer 64

right

Answer 65

Virus not considered Living Organisms because they

have a Nucleic Acid core (DNA or RNA)
infect living cells
are too small
show the characteristics of life only inside living cells

Answer 66

An Obligate Intracellular Parasite

Always need cells for cellular respiration
Some times require living cells to reproduce
Can not live and reproduce by themselves
Infect only Parasites

Answer 67

show characteristics of life only in the host

Answer 68

Viruses contain

Nucleic Acid core (DNA or RNA)
No Proteins or Enzymes
Small mitochondria
Unusual ribisomes
No genetic information of their own

Answer 69

good

Answer 70

cannot live and reproduce by themselves

Answer 71

The Retrovirus

was first found in Retrorockets
requires reverse transcriptase in the cell
reads DNA in an opposite direction from normal
contains backward DNA

Answer 72

right

Answer 73

virus contain either dna or rna

Answer 74

A Virus binds to cell membrane receptors

That are composed of Glycoproteins in cell membranes
That are non specific so they can enter any cell
That are found inside the cell

Answer 75

right

Answer 76

The order of the steps in a Virus Life Cycle

Assembles new virus particles
Lysis of cell, releasing new viruses
Binds to specific cell membrane receptor
DNA inserted into Host DNA (May be quiet for years, 30!)
Enters the cell & leaves protein Coat outside
Makes more virus DNA (or RNA) & virus protein

1,2,3,4,5,6
2,6,1,3,4,5
5,1,3,2,6,4
3,5,4,6,1,2
6,4,5,2,1,3

Answer 77

did n't learn much about the retrovirus except that it is related to having rna like the swine flu or avian flu.. I'll guess the transcriptase

Answer 78

viruses are nonspecific

Answer 79

yes ur guess is right

Answer 80

2,6,1, 3,4,5

Answer 81

they specific like bacteriophage attacks bacterial cell

Answer 82

read the orders of the steps in a Virus Life Cycle again

Answer 83

yes, bacteriophages attack within their host range usually so they would attack bacteria- like in viral replication where if you were in the lab and made a lawn of bacteria then introduced the bacteria we would see plaques where the bacteria was dying the bacteriophage growing

Answer 84

did u get it

Answer 85

sorry I picked one of the multiple choice.. trick question I see it.. I'll fix it

Answer 86

Which of the following is NOT a Characteristic of Microorganisms

Small populations in large areas
Free living single cells, or colonial with limited coordination
Small (need magnification)
Rely primarily on asexual reproduction
Aquatic or moist environments

Answer 87

A rod shaped bacteria is called a

Bacillus
Coccus
Spiral

Answer 88

Bacteria can be Identified

by looking at unstained cells under high power of a microscope
Staining Characteristics = Gram + or Gram _
Colonial Morphology (petri dishes)
Metabolism
by using B, C, & D above

Answer 89

3,5,4,6,1,2

Answer 90

right

Answer 91

small population

Answer 92

bacillus

Answer 93

b,c,d

Answer 94

right

Answer 95

r u satisfied with urself or not

Answer 96

thank you. I still have some things to work through. I will do so