Microbial structure and classification Flashcards Preview

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Flashcards in Microbial structure and classification Deck (17):
1

What cell wall component is unique to Fungi?

Chitin

2

Bacteria that stain blue/purple are likely to be what type of bacteria and why?

Gram Positive cocci or rods

Low lipid composition

3

Bacteria that stain red are likely to be what type of bacteria and why?

Gram Negative cocci or rods

High lipid composition

4

What is cell wall in gram positive bacteria made up of?

Thick peptidoglycan layer made up of repeating units of NAM-peptide and NAG, as well as Lipoteichoic acid and Teichoic acid

Inner cytoplasmic membrane phospholipid bilayer

 

 

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5

ZN stain is used for what bacteria and why?

Mycobacterium Tuberculosis - The waxy mycolic acid of acid-fast bacilli

6

What is the cell wall in gram negative bacteria made up of?

Outer membrane phospholipid bilayer which contains LPS, Porins

Thin Peptidoglycan layer made up of repeating units of NAM-peptide and NAG

Inner cytoplasmic membrane phospholipid bilayer

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7

Which type of bacteria (G +ve or G -ve) contains spore-formers?

Gram Positive

8

Which type of bacteria (G +ve or G -ve) are resistant to desiccation?

Gram Positive

9

Which type of bacteria (G +ve or G -ve) produce exotoxins?

Gram Positive

10

Which type of bacteria (G +ve or G -ve) have endotoxin within their cell wall?

Gram Negative

11

True or False: Gram Negative bacteria do not survive drying.

True

12

What is the main difference between endotoxins and exotoxins?

Exotoxins are highly specific to a particular substrate.

13

Name 2 diagnostic techniques used to identify a viral infection using a patient's serum?

  1. ELISA -Detects the presence of antibodies or antigens in the blood serum.
  2. PCR of serum - Detects Viral RNA and DNA.

14

How are Gram Positive Cocci classified?

  • Staphylococci - form clusters in culture

Coagulase test is used to differentiate between different Staphylococci - Staph aureus is coagulase positive

Coagulase negative staphylococci are generally opportunistic pathogens

  • Streptococci - form pairs and chains in culture

Their effect on blood cells is what is used to differentiate between different Streptococci.

Beta-haemolytic streps cause complete lysis of RBCs - Streps A, B, C

Alpha-haemolytic streps cause incomplete lysis of RBCs - Strep pneumoniae

Non haemolytic streps do not cause lysis of RBCs

- Enterococci, anaerobes

15

What function of gram positive bacteria can be used to differentiate between different gram positive rods?

Whether or not they produce spores

 

Form spores - Anthrax, Tetanus, Botulism

Do not form spores - C. diphtheriae, Nocardia

16

Give two examples of gram negative cocci and the diseases they cause.

Neisseria Meningitidis - Meningitis

Neisseria Gonorrhoea - Gonorrhoea

17

Give examples of gram negative rods.

E. coli

Salmonella

Shigella

Legionella

Campylobacter

Pseudomonas

Proteus

Klebsiella