Introduction to Microbes

Question 1

What are microorganisms?

Answer 1

Organsims too small to be seen by the unaided eye

They make life possible, produce foods, and cause disease

Question 2

What is a prokaryote and what is a eukaryote?

Answer 2

Prokaryote = A cell with NO nucleus due to a lack of internal membranes (bacteria or archaea)

Eukaryote = A cell with a clearly defined nucleus and a surrounding nucleus membrane

Question 3

What are examples of cellular miroorganisms?

Answer 3

Bacteria
Archaea
Fungi
Protists

Question 4

What are examples of acellular microorganisms?

Answer 4

Viruses
Viroids / Virusoids
Prions

Question 5

What are the characteristics of bacteria?

Answer 5

Single celled prokaryote
Cell walls contain peptidoglycan
Ubiquitous in environment and human microbiome

Diseases = caries, periodontitis, skin infections, food poisoning etc

Question 6

What are the characteristics of archaea?

Answer 6

Single celled prokaryote
No peptidoglycan in its cell walls
Unique membrane lipids
Found in extreme environments

(High temp = thermophiles, High salt = halophiles)

Question 7

What are the characteristics of fungi?

Answer 7

Eukaryotes in a diverse group (90,000 identifed by 1.5 million may exist)
Can be unicellular (yeasts) or multicellular (moulds / mushrooms)
Plays a role in oral thrush

Question 8

What are protists?

Answer 8

Any eukaryotic organisms that is not an animal, plant, or fungus
EXAMPLES = Algae, Protozoa, and various moulds which can appear as fungi at different stages of life

Question 9

What are viruses, viroids, and virusoids?

Answer 9

Not living entities, acellular
Must have a host cell to multiply

Virons = simplest form (protein + nucleic acid)
Viroids = circular RNAs that are infectious pathogens (plant diseases)
Virusoids = nucelic acids, animal diseases

Question 10

What are prions?

Answer 10

Acellular proteins that are misfolded and possess the ability to transmit thier misfolded shape into normal variants of the same protein

EXAMPLE = mad cow disease

Question 11

What are Koch’s postulates?

Answer 11

1. Microorganisms must be present in every disease and in every healthy case
2. The suspected micro-organism must be isolated and grown in pure culture
3. The same microorganism must be reisolated from the diseased host