Lecture One

Question 1

Define the term microorganism

Answer 1

A very small organism

Question 2

How are microorganisms classified

Answer 2

Bacteria
Viruses
Fungi
Parasites

Question 3

What is the approx size of prokaryote

Answer 3

0.5-3micrometers

Question 4

What is the difference between prokaryote nucleus and eukaryotesnucleus

Answer 4

Prokaryote nucleus has no membrane

Question 5

Describe the differences in chromosomes of prokaryotes and eukaryotes

Answer 5

Pro- single, circular, haploid

Euk- strands of DNA, diploid

Question 6

Describe the difference in cell wall of prokaryotes and eukaryotes

Answer 6

Prokaryotes have a cell wall complex in structure

Eukaryotes do not have cell wall (except for fungi, which do)

Question 7

Describe a prokaryote ribosome

Answer 7

70S (50s+30s)

Question 8

Describe a eukaryote ribosome

Answer 8

80s (40s+60s)

Question 9

Describe differences in reproduction in prokaryotes and eukaryotes

Answer 9

Pro- asexual reproduction. Binary fission

Euk- sexual and asexual reproduction

Question 10

How is the flagellum different in prokaryote and eukaryote?

Answer 10

Pro- simple flagellum

Euk- complex flagellum

Question 11

How is respiration different in pro and euk?

Answer 11

Pro- via cytoplasmic membrane as mitochondria are absent

Euk- via mitochondria

Question 12

Describe the presence of certain organelles (ER, Golgi, mitochondria) in prokaryote vs eukaryote

Answer 12

Pro- no ER, Golgi or mitochondria

Question 13

Describe the shapes of the following:

Coccus
Bacillus
Coco bacillus
Vibrio
Spirillum
Spirochete
Fusiform bacillus

Answer 13

Coccus- round 
Bacillus- rod shaped
Cocco bacillus- oval
Vibrio- banana
Spirillum- zig zag
Spirochete- spiral 
Fusiform- elongated pointy rod

Question 14

What are endospores?

Answer 14

• Metabolically inactive spores produced by bacillus and clostridium species
• resistant to heat, cold, drying, many chemicals
• can survive many years in soil, dust
• will germinate after landing in nutritious environment (moist, nutrient rich surface)
• not for reproduction

Question 15

What is the purpose of a flagella?

Answer 15

Provide motility

Question 16

How is the flagella powered?

Answer 16

By proton-motif force

Question 17

What are fimbrae?

Answer 17

• hair like structures
• not associated with motility
• aka pili
• contain tip used to bind to host cells (colonisation)
• sex pili used for transfer of genetic material (conjugation)

Question 18

What are slime layers?

Answer 18

• Gelatinous material secreted from cells
• used for gliding and aggregation
• and the formation of biofilms e.g. Plaque

Question 19

Describe bacterial capsules

Answer 19

• composed of polysaccharide
• firmly attached to cell surface
• for protection from desiccation
• for immune system invasion

Question 20

Briefly describe Aristotle’s theory

Answer 20

Spontaneous generation of life from non-living matter

Belief was unchallenged for more than 2000years

Question 21

What did Pasteur prove?

Answer 21

• air contained spores of living organisms

- disproved theory of spontaneous generation

Question 22

What are extremophils?

Answer 22

Microorganisms specialised in living under extreme conditions

Question 23

List some examples of extremophils

Answer 23

Halophiles- need high salt conditions
Thermophiles- thrive between 60-120 degrees C
Cryophiles- best grown below 15degrees C
Acidophile- optimum pH at or below 3
Alkaliphile- optimal growth at pH 9 or above
Xerophile- can grow in extremely dry desiccating conditions

Question 24

Who discovered microorganisms?

Answer 24

Anton van Leeuwenhoek (1676)
Was a tailor
- used lens to examine cloths
- called them animalcules

Question 25

wht is an isolate?

Answer 25

pure microbial sample obtained from an infected individual

Question 26

What is a strain?

Answer 26

Strain: genetic variant or a species (subtype)

Question 27

What is a serotype?

Answer 27

subtype that can be classified using specific antibodies (e.g. E. coli 0157 H7)

Question 28

What is a pathovar?

Answer 28

subtype with tissue/host with specificity e.g. UPEC or Pseudomonas syringae actinidiae (PSA) found in kiwi fruit.

Question 29

What is used to distiguish between gram positive and gram negative bacteria?

Answer 29

Cell wall morphology.

gram positive will stain purple blue and gram negative will stain red due to differences in cell wall morphology

Question 30

Give examples of how microorganisms are used in the manufacturing process

Answer 30

• Foods: bread, butter, cheese. Yogurt, salami
• Alcoholic drinks: beer wine, sake, sherry, whiskey
• Chemicals: acetic acid, butanol, citric acid, glycerol
• Vitamins: ascorbic acid, float, riboflavin
• Antibiotics: penicillin, cephalosporins, streptomycin etc