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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

What are the 5 steps in viral replication?

- Attachment
- Entry
- Uncoating
- Nucleic acid and protein synthesis
- Assembly
- Release