Reintro to Microbiology Flashcards

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1
Q

Name the major types of microorganisms

A
  • Eukaryotic - protazoa and fungi
  • Fungi
  • Bacteria - prokaryotes
  • Viruses
  • Prions - infectious proteins
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2
Q

Protozoa features?

A
Unicellular eukaryotes
2-100μm
Many are free living
e.g. Malaria
Often affect the immunocompromised
Mainly a threat in developing countries
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3
Q

Fungi features?

A

Eukaryotic organisms with a variety of forms
Commercially important- baking, brewing
External, rigid cell wall- containing chitin
Filamentous or yeast forms
Many are dimorphic = ability to have 2 lifestyles
e.g. Candida

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4
Q

Bacteria features?

A

Most numerous organisms
Adapted to inhabit almost all habitats
- Even those not based on sunlight- deep sea vents
Responsible for PLAGUE
Produce a range of toxins- virulence factors
Specialised cell walls
Prokaryotes - no internal membranous compartments

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5
Q

How to classify bac?

A
  1. Cellular form
    - Cocci (1)
    - Diplococci (2)
    - Tetrads (4)
    - Sarcina (4 behind 4)
    - Streptococci (wiggly)
    - Staphylococci (kite shape)
    Baclli:
    Branching
    Extended irregular rods
    Kidney bean
    Corkscrew
    Helical
  2. Cell wall structure
    - Gram positive - 1 membrane = fuzzy part is peptidoglycan layer = retains stain = purple
    - Gram neg - 2 membranes and thin cell wall between the 2 = perioplasmic space = do not retain stain = pink/red stain
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6
Q

What is a peptidoglycan?

A

A polymer of N-acetyl muramic acid (NAM) and N-acetyl glucosamine (NAG)
Crosslinked via AA pentapeptides and anchored to cell wall

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7
Q

What surface structures do bac have?

A

Flagellum = allows movement
Pili and fimbriae;
- Proteinaceous filamentous structures
- Used for attachment to host cells or surfaces
- Adhesins at the tip for host interaction
- Used for twitching motility
- Pseudomonas spp.

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8
Q

What are pathogens? Example?

A

Disease causing bac e.g. Vibrio cholera - cholera

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9
Q

What are opportunistic pathogens?

A

Commensals that sometimes cause disease e.g. MRSA, N.meningitis

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10
Q

Where are commensals located? How much is there?

A

Main mass in digestive tract

1kg mass in bac

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11
Q

What are commensals?

A

Unseen hordes - mainly harmless, colonise surfaces and mucosa

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12
Q

What makes mycobacteria different?

A

Have a normal membrane, peptidoglycan and mycolic acids = more resistant = unusual cell well

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13
Q

Features of mycobacterium spp? Example of a mycrobacterium?

A

Gram pos rods, unusual cell wall - mycolic acid
Impervious to gram staining
Zeen Ziehl-Neelson acid fast staining procedure; mycobacteria in red
E.g M. tuberculosis

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14
Q

M.leprae significance? E.g of mycobacterium

A

First bac clinically associated with a disease - leprosy

Treated with antibiotics

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15
Q

What causes chlamydia? Histological Features, Life Cycle Features? What does chlamydia cause?

A
Organism : C.trachomatis
Histology: Unusual gram neg cell wall
Life Cycle: Unusual life cycle - elementary body facilitates spread, reticulate body (intracellular replication)
Clinically: Urethral and vaginal infec
Conjunctivitis
Infertility and ectopic pregnancies
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16
Q

Examples of diseases as a carrier state?

A

Gonnorhoea, chlamydia

17
Q

What causes typhoid fever? Effects of this?

A

Salmonella typhi

Microorganisms remain in gall bladder and excreted in faeces when cured of typhoid fever = spread

18
Q

Virus features?

A

Obligate intracellular parasites
Causes HIV
Unable to reproduce without host factors
Viral genome uses host to encode viral proteins

19
Q

Outline the basic viral structure

A

Nucleic acid encapsulated by proteinaceous capsid
Varying shape and symmetry
Some further coated with lipid coat - enveloped e.g. HIV

20
Q

What is viral latency?

What is retroviral replication?

A

Infec does not result in lytic cycle

  1. Incorporation into genome
  2. Latent infec of host cell away from site of infec

Retroviral replication;
- mRNA does reverse transcription forming DNA - incorporates into genome of hose = replicates e.g. HIV

21
Q

Why is the lytic life style of viruses?

A

Virus internalised, host cell makes many copies of virus = released from cell

22
Q

What can latent infections do?

A

Can re-activate e.g. due to stress

23
Q

What do bacteriophages do? (is a virus)

A

Attack and kill bacteria - live in mouth

24
Q

Prion features?

A

Not truly a microorganism but is an infectious agent
Heat resistant, filterable, stick to instruments
Can be detected in tonsils but not outside lymphatics
e.g. CJD
Aggregate into long fibres and amyloid plaques
Likely transmission via brain tissue
E.g KURU

25
Q

What is Kuru? Symptoms and cause?

A

Fatal brain disorder
First symptoms = unsteady gut, tremors, slurred speech
Caused by cannibalism