Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology (DEN 303) > Re-introduction to microbiology > Flashcards

Re-introduction to microbiology Flashcards

The properties of bacteria including: morphology, staining and culture; taxonomy; commensals and carriers. The properties of viruses including: characteristic features of viruses; elementary taxonomy; outlines of structure and replication; principles of latent viral infection. The properties of fungi and protozoa: features of medically important fungi; laboratory diagnosis of these infections. The properties of Prions: -relationship to spongiform encephalopathies; -practical difficulties for ste

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

The micro-organisms

A 
Protozoa (eukaryotes)
Fungi (eukaryotes)
Bacteria (prokaryotes)
Viruses
Prions (infectious 'rogue' proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Protozoa

A

Unicellular eukaryotes
2-100 μm
Many are free-living e.g. euglena (pond-water)
Several are important human pathogens (malaria)
Often affect the immunocompromised
Mainly a threat in developing countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Protozoa examples

A 
Trypanosomiasis (chagas disease)
-South America kissing bug
Malaria
Cryptosporidium (causes diarrhoeic diseases in bad water)
-chlorinated swimming pools
Toxoplasma gondii
-crazy cat lady
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Fungi

A

Eukaryotic organisms with a variety of forms
Commercially important - baking, brewing and pharmaceuticals
External, rigid cell wall - containing chitin
Filamentous or yeast forms
Many display both - dimorphic e.g. Candida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Bacteria

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cellular forms

A 
Cocci
-cocci, diplococci, tetrads, sarcina, streptococci, staphylococci
Bacilli
Extended irregular rods
Kidney bean
Corkscrew
Helical
Gram positive and gram negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diplococci example

A

Neisseria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sarcina

A

Gram positive cocci

Genus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Streptococci example

A

Streptococcus mutans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Staphylococci example

A

Staphylococcus aureus MRSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Bacilli example

A

Bacillus subtilis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Extended irregular rods example

A

Fusobacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Kidney bean example

A

Vibrio spp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Corkscrew example

A

Treponema spp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Helical example

A

Campylobacter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Gram positive

A

Thick cell wall made of peptidoglycan

Retain crystal violet stain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gram negative

A 
Do not retain stain
Coloured red or pink
More resistant against antibodies because of impenetrable cell wall
Thin (single-layered) cell wall
Periplasmic space
LPS on outside with porin in between
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Peptidoglycan

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Surface structures

A

Flagellum

Pili and fimbriae

20
Q

Pili and fimbriae

A 
Proteinaceous filamentous structures 
Often used for attachment to host-cells or surfaces
Adhesins at the tip for host interaction
- e.g. EPEC bfp 
Can also be used for twitching motility
21
Q

Pili and fimbriae example

A

Pseudomonas spp.

22
Q

Pathogens with 2 examples

A

Disease causing bacteria

e. g. Vibrio cholera - Cholera
e. g. Yersinia pestis - Plague

23
Q

Opportunistic pathogens with 3 examples

A

Commensals that sometimes cause disease
e.g. MRSA, C. difficile, Major hospital infections
N.meningitidis- isolated epidemics in UK

24
Q

Commensals

A

The unseen hordes
Mainly harmless
Colonise surfaces and mucosa

25
Q

Commensals examples

A

Staphylococcus epidermidis: harmless commensal gram positive cocci
Propionibacterium acne: gram positive bacilli- can cause acne
Staphylococcus aureus: carriage in anterior nares and skin
-gram positive cocci - MRSA

26
Q

Digestive tract in terms of bacteria

A

Main reservoir of bacteria within the body 1,000,000,000 per gram
Around 1kg mass in bacteria

27
Q

Examples of bacteria in the digestive tract

A 
E. Coli:  
-gram negative rod
-essential commensal
-some strains are Pathogenic
Bacteroides species:
-gram-negative anaerobic bacilli
-most numerous in the body
Clostridia species: 
-gram positive anaerobic spore forming bacilli                            
-includes C. difficile an increasingly 
drug resistant
-related to tetanus and botulism causing bacteria
28
Q

Mycobacterium spp. (unusual example 1)

A

Gram positive rods, unusual cell wall- mycolic acid (lipolitic sugars)
Impervious to gram-staining
Need Ziehl-Neelsen acid-fast staining procedure: mycobacteria in red

29
Q

Mycobacterium spp. examples

A

M. tuberculosis
M. leprae
-first bacteria to be clinically associated with a disease (leprosy)
-Leprosy-Hansens disease

30
Q

Leper colonies

A

Leper colonies persisted until relatively recently in poorer countries, only 1 remaining in Europe (Romania - people stay there now by choice)
Treatable with antibiotics- Dapsone and rifampicin
NOT thalidomide

31
Q

Chlamydia (unusual example 2)

A 
C. trachomatis
Extremely unusual life cycle: 
-elementary body facilitates spread 
-reticulate body- intracellular replication
Small- 0.4 microns
STI
-urethral and vaginal infection 
-conjunctivitis - trachoma
-infertility (ectopic pregnancy) 
-asymptomatic carriage important in spread
32
Q

Flagellum

A

Spins around moving electrons across the membranes so can move around
Electric motor built from scratch in membranes

33
Q

The carrier state + 2 examples

A

Asymptomatic carriage of pathogenic bacteria

Examples: gonnorhoea, chlamydia

34
Q

Why is the carrier state a problem?

A

Important in disease transmission esp for gon, HIV, and typhoid- gall bladder- famous example
Case of Thypoid Mary - Salmonella typhi - thyphoid fever
-small % remain in gall bladder –> faeces
-so can transmit with poor hygiene (working with food also dangerous)

35
Q

Viruses

A

Obligate intracellular parasites
Cause of major world epidemics:
e.g. H1N1: 1918 Flu 20 million deaths, HIV
Unable to reproduce without host factors
Viral genome uses host to encode viral proteins

36
Q

Basic viral structure

A

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

37
Q

Lytic life cycle

A

Attach, invade, replicate, break out

38
Q

Viral latency

A

Infection does not necessarily result in lytic cycle

  1. Incorporation into genome – retrovirus
  2. Latent infection of host cell away from site of infection e.g. Herpes, Varicella zoster
39
Q

Retroviral replication + example

A

mRNA –reverse transcription–> DNA –> into nucleus, integration into host genome –transcription–> mRNA –> viral proteins and RNA genome
e.g. HIV sits in CD4 cells

40
Q

Latent infection vs re-activcation

A

Latent e.g. Herpes simplex virus in response to mild pharygitis fever, varicella (chickenpox)
Leads to recurrence
Cold sore due to fever, sunlight, menstruation and zoster (shingles) due to age, immunocompromise and local injury

41
Q

Thalidomide

A

Removes symptoms but not disease

Can lead to people being born with malformed limbs

42
Q

Bacteriophage

A

Bacteria eaters
Capsid head, tail and fibres
Most numerous organisms on earth !!!- viruses
Attack and kill bacteria- like cold virus attacks you
They live in your mouths - isolated recently

43
Q

Prions

A

Heat resistant, filterable, stick to instruments
Can be detected in tonsils… but not outside lymphatics so far in humans- but in animals…
Scrapie, BSE, CJD (familial, variant and sporadic)
Normal PrPC converted into ‘Rogue’ PrPSC
Aggregate into long fibers and amyloid plaques

44
Q

Prion example

A

KURU - Papua New Guinea
kuru : “trembling with fear” in Fore language
Fatal brain disorder
First symptoms are unsteady gait, tremors, and slurred speech
Epidemic during the 1950s-60s among the Fore people

45
Q

Prions likely transmission

A

via Brain tissue

46
Q

KURU - how and why?

A

Ritualistic cannibalism
Funeral rituals:
-Fore cooked and ate their dead relatives.
‘the mortuary practice of consumption of the dead and incorporation of the body of the dead person into the bodies of living relatives, thus helping to free the spirit of the dead’
Brains eaten mostly by the Fore women and children.
Men rarely affected (up to 40-50yrs incubation…)

Microbiology (DEN 303) (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions