Flashcards in Microbiology Deck (28)
The capacity of an organism to cause damage to the host
How do enveloped and non-enveloped viruses leave a cell?
enveloped leave a cell by lysis
non-enveloped leave a cell by budding
What is the difference between bacteriostatic and bacteriocidal organisms?
Bacteriostatic- inhibit bacteria growth
Bactericidal - kill bacteria
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
What is the nucleoid?
The DNA containing region in prokaryotes
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)
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
List tests used for the identification of viruses
Combined PCR ad mass spectrometry
Do gram negative organisms produce endotoxins or exotoxins?
Do gram positive organisms produces endotoxins or exotoxins?
What colours do gram positive and gram negative stain?
Gram Positive - Purple
Gram Negative - Pink
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.
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
List 3 important groups of GRAM POSITIVE COCCI
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
List the main groups of gram negative cocci
List some coliforms
List some strict aerobes
Gram negative bacilli
Name two spiral/ curved gram negative bacilli
What kind of organism - clostridium
Gram positive anaerobic bacilli
What kind of organism - haemophilia influenza
Small gram negative bacillus
What are the three steps in gene transfer in bacteria?
What is meant by bactericidal and bacteriostatic
Bactericidal - Kills bacteria
Bacteriostatic - Inhibits bacteria growth
Name a narrow spectrum antibiotic and a broad spectrum antibiotic
Narrow spectrum - penicillin
Broad spectrum - Tetracycline
Which antibiotic groups work on the cell wall?
Which antibiotic groups inhibit protein synthesis?
Macrolides, tetracyclines, aminoglycosides
Which antibiotic groups act on bacterial DNA?