Microbiology

Question 1

Define Virulence

Answer 1

The capacity of an organism to cause damage to the host

Question 2

How do enveloped and non-enveloped viruses leave a cell?

Answer 2

enveloped leave a cell by lysis

non-enveloped leave a cell by budding

Question 3

What is the difference between bacteriostatic and bacteriocidal organisms?

Answer 3

Bacteriostatic- inhibit bacteria growth

Bactericidal - kill bacteria

Question 4

State the use of haemolysis and describe the different types

Answer 4

Used only for classification of streptococci

Alpha haemolysis = PARTIAL - GREEN
Beta haemolysis - COMPLETE - YELLOW
Gamma - haemolysis - NONE

Question 5

What is the nucleoid?

Answer 5

The DNA containing region in prokaryotes

Question 6

What is the difference in the peptidoglycan layer between gram positive and gram negative organisms?

Answer 6

Gram +ve - Thick peptidoglycan (multi-layer)

Gram -ve - Thin peptidoglycan (single layer)

Question 7

What are spores? What is significant about them?

Answer 7

small dehydrated chromosomes which are resistant to chemical and physical change - they can therefore survive in unfavourable conditions

Question 8

List tests used for the identification of viruses

Answer 8

PCR 
NAATs 
Electron microscopy 
Cell cultures 
Combined PCR ad mass spectrometry

Question 9

Do gram negative organisms produce endotoxins or exotoxins?

Answer 9

Endotoxins

Question 10

Do gram positive organisms produces endotoxins or exotoxins?

Answer 10

Exotoxins

Question 11

What colours do gram positive and gram negative stain?

Answer 11

Gram Positive - Purple

Gram Negative - Pink

Question 12

Bacteria grow by binary division which can occur in aerobic, microaerophilic or anaerobic conditions, what does each of these refer to?

Answer 12

Aerobic - Occurs in the presence of oxygen (air).

Microaerophlic - Occurs in reduced oxygen and enriched CO2 conditions.

Anaerobic - Occurs when no oxygen is present.

Question 13

Describe what is meant by exotoxins and endotoxins

Answer 13

An exotoxin is produced inside the cells or gram positive bacteria

An exotoxin usually forms part of a gram negative bacterial cell wall

Question 14

List 3 important groups of GRAM POSITIVE COCCI

Answer 14

Streptococcus
Enterococcus
Staphylococus

Question 15

What does production of prostaglandin E during fever cause?

Answer 15

prostaglandin E resets the body’s thermal set point so the body perceives itself as being cold and therefore tries to conserve heat

Question 16

List the main groups of gram negative cocci

Answer 16

Diplococci
Aerobic
Neisseria Gonorrhoea
Neisseria Meningitidis

Question 17

List some coliforms

Answer 17

E. Coli
Klebsiella
Salmonella
Shigella

Question 18

List some strict aerobes

Answer 18

Gram negative bacilli
Pseudomonas aeruginosa
Legionella pneumophilia

Question 19

Name two spiral/ curved gram negative bacilli

Answer 19

Campylobacter

Helicobacter pylori

Question 20

What kind of organism - clostridium

Answer 20

Gram positive anaerobic bacilli

Question 21

What kind of organism - haemophilia influenza

Answer 21

Small gram negative bacillus

Question 22

What are the three steps in gene transfer in bacteria?

Answer 22

Transformation
Conjugation
Transduction

Question 23

What is meant by bactericidal and bacteriostatic

Answer 23

Bactericidal - Kills bacteria

Bacteriostatic - Inhibits bacteria growth

Question 24

Name a narrow spectrum antibiotic and a broad spectrum antibiotic

Answer 24

Narrow spectrum - penicillin

Broad spectrum - Tetracycline

Question 25

Which antibiotic groups work on the cell wall?

Answer 25

Penicillin Cephalosporins Glycopeptides

Question 26

Which antibiotic groups inhibit protein synthesis?

Answer 26

Macrolides, tetracyclines, aminoglycosides

Question 27

Which antibiotic groups act on bacterial DNA?

Answer 27

Metronidazole Fluoroquinolones Trimethoprim

Question 28

What are the 5 steps in viral replication?

Answer 28

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