Micro-organisms and Health (week 5) Flashcards

1
Q

what is the role of bacterial pili / fimbriaea

A

hair like structures that aid adhesion to host cells

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2
Q

what colour are gram positive bacteria and why?

A

purple - many layers of peptoglycen in cell wall: keeps purple stain in and drugs out

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3
Q

what colour are gram negative bacteria and why?

A

pink - few layers of peptoglycen, stain washes out

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4
Q

What type of bacteria is S. aureus?

A

Gram +ve coccus

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5
Q

What type of bacteria are Helicobacter and Campylobacter?

A

Spiral

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6
Q

What type of bacteria is E. Coli?

A

Gram negative bacillus

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7
Q

Name a gram negative coccus bacteria

A

Neisseria meningiditis

Neisseria gonorrhoea

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8
Q

What type of bacteria is C. diff?

A

Gram positive bacillus

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9
Q

Name a gram negative coccobacilli

A

Haemophilus
Bordetlla
Brucellla
Pasteurella

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10
Q

Describe how bacteria replicate by binary fission

A

cells divide to give 2 identical daughter cells, no exchange of genetic material

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11
Q

Describe how bacteria replicate by conjugation

A

Conjugation tube forms between 2 bacteria and plasmid DNA is passed from one to another. Does not create new bacteria but genetic material is exchanged

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12
Q

Describe how bacteria replicate by transformation

A

Plasmids picked up from environment surrounding bacteria

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13
Q

Describe how bacteria replicate by transduction

A

Transfer of genetic material via a viral vector

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14
Q

What is fungi cell wall made from?

A

Chitin

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15
Q

Name the 2 classes of disease causing fungi

A

Yeats

Filamentous moulds

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16
Q

What are helminths?

A

Parasitic worms

17
Q

How do parasites reproduce?

A

Asexually through fission

18
Q

What kind of nucleic acid does a virus contain?

A

DNA or RNA
Double or single stranded
Sense or antisense

19
Q

Briefly describe the stages of viral replication

A
  1. Attachment / penetration of host
  2. Release genome from protein coat
  3. Produce early viral proteins
  4. Genome replication in host nuclues
  5. Produce late viral proteins - structural / capsid
  6. Assembly of virion
  7. Virion release
20
Q

how do retroviruses replicate?

A

reverse transcriptase enzyme converts RNA to DNA, which is then integrated into host DNA
host replication system then used

21
Q

How do prions cause disease?

A

Aggregate and cause misfolding of native proteins

22
Q

Name some diseases caused by prions

A

Creutzfeld-Jakob
Bovine spongiform
Encephalopathy
Scrapie

23
Q

What is the definition of microbiota?

A

All organisms in a given community

24
Q

What is commensalism?

A

one organism benefits, the other derives neither benefit or harm

25
What is the types of bacteria are the most common bacteria found on the skin?
coagulase-negative staphylococci | staph aureus
26
What type of bacteria is found in the mouth flora?
viridians / oral staphylococci
27
How does vaginal flora differ pre and post puberty?
After puberty, circulating oestrogen causes glycogen production, meaning C. albicans can colonise
28
True or false: the majority of bacteria found in the large intestine are aerobes
False - they are anaerobes
29
How does normal microbiota aid metabolism?
synthesises secondary metabolites / vitamins e.g. vit K, vit B12 ferment unused energy substrates
30
How does normal microbiota help resist colonisation of other species?
environmental manipulation e.g. lowering pH | produce anti-bacterial agents e.g. colicins, bacteriocins, fatty acids, metabolic waste products
31
Which bacteria normally cause superficial abscesses
S. Pyogenes | S. auereus
32
What is the host response to endotoxins?
Severe sepsis / septic shock Clinical features of infection Activation of clotting cascade can lead to DIC
33
What is meant by 'incubation period' and 'period of inactivity'
1. period between infection with organism and manifestation of clinical features 2. period during which transmissible organisms may be transmitted to another person