Flashcards in Microbiology Deck (28)
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1
Define Virulence
The capacity of an organism to cause damage to the host
2
How do enveloped and non-enveloped viruses leave a cell?
enveloped leave a cell by lysis
non-enveloped leave a cell by budding
3
What is the difference between bacteriostatic and bacteriocidal organisms?
Bacteriostatic- inhibit bacteria growth
Bactericidal - kill bacteria
4
State the use of haemolysis and describe the different types
Used only for classification of streptococci
Alpha haemolysis = PARTIAL - GREEN
Beta haemolysis - COMPLETE - YELLOW
Gamma - haemolysis - NONE
5
What is the nucleoid?
The DNA containing region in prokaryotes
6
What is the difference in the peptidoglycan layer between gram positive and gram negative organisms?
Gram +ve - Thick peptidoglycan (multi-layer)
Gram -ve - Thin peptidoglycan (single layer)
7
What are spores? What is significant about them?
small dehydrated chromosomes which are resistant to chemical and physical change - they can therefore survive in unfavourable conditions
8
List tests used for the identification of viruses
PCR
NAATs
Electron microscopy
Cell cultures
Combined PCR ad mass spectrometry
9
Do gram negative organisms produce endotoxins or exotoxins?
Endotoxins
10
Do gram positive organisms produces endotoxins or exotoxins?
Exotoxins
11
What colours do gram positive and gram negative stain?
Gram Positive - Purple
Gram Negative - Pink
12
Bacteria grow by binary division which can occur in aerobic, microaerophilic or anaerobic conditions, what does each of these refer to?
Aerobic - Occurs in the presence of oxygen (air).
Microaerophlic - Occurs in reduced oxygen and enriched CO2 conditions.
Anaerobic - Occurs when no oxygen is present.
13
Describe what is meant by exotoxins and endotoxins
An exotoxin is produced inside the cells or gram positive bacteria
An exotoxin usually forms part of a gram negative bacterial cell wall
14
List 3 important groups of GRAM POSITIVE COCCI
Streptococcus
Enterococcus
Staphylococus
15
What does production of prostaglandin E during fever cause?
prostaglandin E resets the body's thermal set point so the body perceives itself as being cold and therefore tries to conserve heat
16
List the main groups of gram negative cocci
Diplococci
Aerobic
Neisseria Gonorrhoea
Neisseria Meningitidis
17
List some coliforms
E. Coli
Klebsiella
Salmonella
Shigella
18
List some strict aerobes
Gram negative bacilli
Pseudomonas aeruginosa
Legionella pneumophilia
19
Name two spiral/ curved gram negative bacilli
Campylobacter
Helicobacter pylori
20
What kind of organism - clostridium
Gram positive anaerobic bacilli
21
What kind of organism - haemophilia influenza
Small gram negative bacillus
22
What are the three steps in gene transfer in bacteria?
Transformation
Conjugation
Transduction
23
What is meant by bactericidal and bacteriostatic
Bactericidal - Kills bacteria
Bacteriostatic - Inhibits bacteria growth
24
Name a narrow spectrum antibiotic and a broad spectrum antibiotic
Narrow spectrum - penicillin
Broad spectrum - Tetracycline
25
Which antibiotic groups work on the cell wall?
Penicillin
Cephalosporins
Glycopeptides
26
Which antibiotic groups inhibit protein synthesis?
Macrolides, tetracyclines, aminoglycosides
27
Which antibiotic groups act on bacterial DNA?
Metronidazole
Fluoroquinolones
Trimethoprim
28
