Microbiology Flashcards
(139 cards)
1
Q
Define nucleocapsid
A
The capsid most closely associated with the viral nucleic acid.
Nucleic acid + capsid
2
Q
What is the size of a virus?
A
0.02 - 0.04 um
= 20 - 40 nm
3
Q
Define virion
A
The virus particle
4
Q
What does a high lymphocyte count indicate?
A
Viral infection
5
Q
Define the viral envelope
A
Lipid membrane surrounding either the capsid or nucleocapsid that is formed by the host cells’ membrane (not present in all viruses)
6
Q
What do naked viruses lack?
A
An envelope
7
Q
Define capsid
A
The protective protein coat shell around the viral genome and forming the core of the virus particle
8
Q
What are the 2 main differences between the gram positive and the gram negative bacterial cell wall?
A
Gram negative bacteria have a smaller/thinner peptidoglycan layer and they have an additional outer/superficial plasma membrane.
9
Q
What type of bacteria is this?
A
Spirochete
10
Q
What is the funciton of the bacterial flagella?
A
Locomotion
11
Q
What type of bacteria is this?
A
Diplococci
12
Q
What are the 3 main components of the bacterial peptidoglycan cell wall?
A
N-acetyl-glucosamine, N-acetyl-muramic acid and a short peptide chain
13
Q
What shape is a bacillus bacteria?
A
Rod
14
Q
What are 3 functions of the bacterial capsule?
A
increases virulence
protects against phagocytosis
prevents dehydration..
15
Q
What type of bacteria is this?
A
Streptococci
16
Q
What is the size of a bacterium?
A
1-2 um
17
Q
What type of bacteria is this?
A
Diplobacillus
18
Q
What type of bacteria is this?
A
Streptobacilli
19
Q
What shape is a coccus bacteria?
A
Spherical
20
Q
In the peptidoglycan wall of the bacterium, how are the peptide chains connected?
A
Pentapeptide bridges
21
Q
What are the 3 most common sites of microbe entry?
A
The GI tract, skin and respiratory tracts
22
Q
Define cellulitis
A
An infection of the deep layers of the skin and subcutaneous tissues by bacteria
23
Q
An offensive smelling wound suggests what?
A
Infection by anaerobic bacteria
24
Q
What type of bacteria release endotoxin?
A
Gram-negative bacteria
25
What does the catalse test assess?
Tests whether microbe can break down hydrogen peroxide: 2H2O2 → 2H2O + O2
26
What does the coagulase test assess?
Tests whether the microbe can clot plasma by converting fibrinogen to fibrin
27
What is CHA medium?
Chocolate horse blood agar: same as HBA but heated to lyse RBCs and release nutrients
28
What type of haemolysis is clear haemolysis?
Beta haemolysis
29
What type of haemolysis is greening haemolysis?
Alpha haemolysis
30
What colour will beta haemolysis create?
Clear
31
What colour will alpha haemolysis create?
Green
32
What is MacConkey agar enriched with?
Bile salts
33
Bright pink appearance on a MAC plate indicates what?
Lactose fermenter
34
Pale appearance on a MAC plate indicates what?
Non-lactose fermenter
35
Where do RNA viruses generally replicate?
in the cytosol
36
When are non-enveloped viruses released from a host cell?
When the host cell lyses
37
What do we call the period between a virus infecting a cell and the intracellular number of viruses rising?
Eclipse period
38
What must a negative strand viruses bring preformed with it when it infects a cell?
RNA-dependent RNA polymerase
39
What are the 2 ways a virus may penetrate a cell?
1 Fuse with the plasma membrane
2 Use receptor mediated endocytosis
40
What do we call the period between a virus infecting a cell and extracellular viruses appearing?
Latent period
41
What do all viruses need to replicate?
plus sense RNA
42
What type of infection is it called when a virus infects a cell, but does not harm the cell and only emerges at a later time as a lytic infeciton
Latent infection (eg herpesvirus)
43
Varicella-zoster, Epstein-Barr and cytomegalovirus are all examples of what 'family' of viruses?
Herpesvirus
44
What is the most important/common route of entry for viruses intot he human body?
Respiratory system
45
What type of symetry does the capsid of all non-enveloped viruses have?
An icosahedral structure.
46
What type of infection is it where a virus infects a cell and slowly releases virus particles without killing the host cell?
Chronic infection
47
What do virus-infected cells release to prevent neighbours from replicating thus protecting them from infection?
Interferons
48
Where are structural virus-encoded proteins translated?
Ribosomes in the cytoplasm of the host cell
49
Which protein does a virus needs to replicate, which humans don't have?
RNA-dependent RNA polymerase
50
Name 2 ways an enveloped virus can leave the host cell
1 Budding off from cell plasma membrane
2 Golgi-formed vesicles are exocytosed
51
Where do DNA viruses generally replicate?
In the nucleus
52
Which helminth can grow up to 30-40 cm?
Ascaris lumbricoides
53
What symptoms do scabies cause?
Intense itchiness and dermatitis
54
What is the only helminth that can complete its life cycle in a human host?
Strongyloides
55
What is a roundworm known as?
Nematode
56
Where may Giardia lamblia live in humans?
Duodenum
57
What are helminths known as?
Worms
58
Which organ does entamoeba histolytica typically invade?
Colon
59
Name two helminths that can infect humans directly though the skin
Schistosoma mansoni
Strongyoides stercoralis
60
What is the pathogen in head lice?
Pediculis capitis
61
What is the pathogen in scabies?
Sarcoptes scabiei
62
What is the pathogen in pubic lice?
Phthirus pubis
63
Which parts of the body do scabies like to infect?
Fingerwebs, elbows, axillae, genitals
64
Which is the most comon disease-causing amoeba in humans?
Entamoeba histolytica
65
Host in which development occurs but the parasite does not reach sexual maturity. How is this descibed?
Intermediate host.
66
What is a very common non-human host of toxoplasma gondii in Australia?
Cats
67
What is enterobius vermicularis better known as?
Pin worm
68
Whihc tick is the pathogenic agent in rapid ascending paralysis?
Ixodes holocyclus
69
What is lice infection generically known as?
Pediculosis
70
Name two type of adhesins used by bacteria
Fimbriae and intimin
71
How do helminths respire?
Through their skin
72
In which countries are schistosoma mansoni likely to be acquired?
Africa, South America, Carribean
73
How many people in the world are infected with a helminth?
\>1 billion
74
What effect does vancomycin have on microbiota?
Vancomycin decreases diversity of microbiota, which may be enduring
75
How does strongyloides stercoralis infect a human?
Through skin
76
How does scabies spread?
Direct skin to skin contact
77
Which helminth causes hydatid cysts?
Echinococcus granulosus
78
What do we call the host in which the parasite reaches sexual maturity?
Definitive host
79
What is the pathogen in body hair lice?
Pediculus humanis
80
How is infection with schistosoma mansonii acquired?
Exposure to infected fresh water
81
Which helminths are known to sit in the gut, consume energy and cause weight loss?
Tapeworms
82
What is a very severe complication of tick infection?
Generalised rapid ascending paralysis
83
Where do ectoparasites live?
On or near dermal surface
84
Which type of helminths cause neurocystercercosis?
Taeniae
85
Define parasite
A plant or animal...
that lives on or in another living organism....
on which it is metabolically dependent
86
Where do body louse lay their eggs?
Clothing
87
What is the classical pathology caused by taenia solium?
Neurocystercercosis
88
Which two bacteria predominate in the gut microbiota?
Fimicutes and bateroidetes
89
Which generations of cephalosporin are better for gram negative bacteria?
Later generations
90
How long must a mosquito have malaria before it can transmit it to a human?
2 weeks
91
What are 4 disadvantages of killed vaccines?
Weaker immune response
High dose
Need adjuvants
Expensive
92
What is pyocyanin?
Turquoise pus produced by eg pseudomonas aeruginosa
93
What is the significance of Ps. aeruginosa being non-fermenting and non-sporing?
It has low nutritional requirements
94
What is the form of malaria that a mosquito may infect a human with?
Sporozoite
95
What stage of the malaria lifecycle is released from hepatocytes?
Merozoite
96
What is the antibiotic of choice for MRSA?
Vancomycin
97
Which type of malaria causes the majority of severe malaria and death?
Plasmodium falciparum
98
What does nosocomial epidemic mean?
Institutional epidemic (eg hospital, nursing home, school)
99
What type of bacteria is pseudomonas aeruginosa? Gram pos/neg, coccus/rod
Gram negative rod
100
What is the main weapon of the immune system in targeting the blood stage of malaria?
Antibodies
101
With diurnal variation, when is temperature lowest?
Morning
102
What are the clinical features of cerebral malaria?
Impaired consciousness, coma, convulsions and long term neurological sequelae
103
What is the single most important preventative technique for opportunistic infections?
Hand hygiene
104
What is the optimum temperatture for immune, endocrine and phsyiological mechanisms?
39.5 C
105
What is group A strep also known as?
Strep pyogenes
106
What oral temperature defines a fever in the morning?
37.2
107
What is the difference between oral temperature and core body temperature?
Oral less than core temp by 0.5C
108
What oral temperature defines a fever at any time of day?
37.8
109
Malaria is most common in people who are travelling for what reason?
Visiting friends or family
110
How long does malaria incubate in the liver for?
7-10 days
111
What is the difference between axillary temperature and core body temperature?
Axillary temp \< core body temp by 1C
112
What does saprophytic mean?
An organism can obtain nutrients from dead organic matter
113
What stage of the malaria lifecycle will infect RBCs?
Merozoite
114
What are the two main types of malaria?
Plasmodium falciparum and plasmodium vivax
115
At what stage of the life cycle is the malaria protozoa when it infects hepatocytes?
Sporozoite
116
Which bacteria will often infect a burn in hospital?
Staph aureus
117
What is a fomite?
An inanimate object capable of carrying microorganisms eg stethoscope
118
If someone presents with an acute fever, what are some warning signs of a more serious underlying illnes?
Rigors, rapid evolution, severe muscle pains, impaired conscious state, vomiting, severe headache, rash, jaundice, hypotension, cyanosis, tachypnoea
119
By what process does pseudomonas aeruginosa turn on/off many genes when in a biofilm?
Quorum sensing
120
What are the symptoms of mild malaria?
Flu like illness with fever, headache and malaise
121
Travelling to what part of the world will give you the highest chance of developing traveller's diarrhoea?
South Asia
122
With diurnal variation, when is temperature highest?
Afternoon
123
Which types of malaria can be transmitted from human to human?
NONE
124
What is the most common mode of disease transmission in a traveller?
Vector borne
125
What are the 3 criteria for pyrexia of unknown origin?
Prlonged illness (2-3 weeks duration)
Fever \> 38.3 on several occasions
No Dx after intelligent Ix
126
Where does pseudomonas aeruginosa love to grow?
In moist environments
127
What is the normal oral temperature range?
35.8-37.8
128
What are 3 disadvantages of living vaccines that can cause disease?
Back mutation
Spread
Contamination
129
What symptoms are evident during the liver stage of malaria?
None
130
What is the most common preventable medical condition in travellers?
Influenza
131
Which is closer to core body temperature: oral, axillary or ear?
Ear
132
What is the main weapon of the immune system in targeting the liver stage of malaria
Cytotoxic T cells
133
Which type of malaria is most common in sub-Saharan Africa?
Plasmodium falciparum
134
What are 4 advantages of killed vaccines?
Stable
Contamination unlikely
Can't spread
Safe for immunodeficient
135
Which nucleus of the hypothalamus controls temperature set point?
Pre-optic
136
What are 3 advantages of living vaccines?
Broader immune response
Local immunity
Ease of administration
137
Which type of malaria is most common in central/South America and south east Asia?
Plasmodium vivax
138
Which generations of cephalosporin are better for gram positive bacteria?
Earlier generations (and 4th generation)
139
What is the antibiotic of choice for staph aureus?
Flucloxacillin
