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Michaelmas Term 1 > The Microbial World And The Tree Of Life > Flashcards

The Microbial World And The Tree Of Life Flashcards

(83 cards)

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1
Q

Robert Hook, Micrographia

A

1660

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2
Q

Ruska, 1931

A

First TEM

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3
Q

von Ardenne, 1937

A

First SEM

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4
Q

Describe TEM

A

Beam of electrons is transmitted through a specimen to form an image

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5
Q

Describe SEM

A

Scans surface with a focussed beam of electrons

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6
Q

STM

A
  • scanning tunnelling microscope
  • imaging at the atomic level
  • Binnig and Heinrich, 1981
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7
Q

ETEM

A
  • environmental transmission microscope
  • collects electron micrographs of wet and/or uncoated specimens in the specimen chamber
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8
Q

Why might a specimen be wet/uncoated

A

Gaseous environment

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9
Q

How can we see viruses?

A

Electron microscopy

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10
Q

How big are viruses?

A

0.05-0.1 micromètre

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11
Q

How can we see mycoplasma?

A

Electron microscopy
Some under light microscopy

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12
Q

How big are mycoplasma?

A

0.1-0.5 micromètres

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13
Q

How can we see bacteria

A

Light microscopy / electron microscopy

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14
Q

How big are bacteria

A

1-10 micromètres

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15
Q

How can we see yeasts

A

Light microscopy / electron microscopy

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16
Q

How big are yeasts

A

3-10 micromètres

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17
Q

How can we see eukaryotic cells

A

Light microscopy
Up to 50 micromètres with electron microscopy

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18
Q

How big are eukaryotic cells

A

> 50 micromètres

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19
Q

How can we see mycelia

A

With the naked eye/ light microscopy

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20
Q

How big are mycelia

A

Bigger than 100 micromètres

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21
Q

Describe viruses

A
  • infectious, often pathogenic
  • typically smaller than bacterium
  • very diverse size, morphology and composition
  • obligate cellular parasites
  • diverse genetic material
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22
Q

What do viruses do?

A

Reprogrammé cellular machinery to replicate themselves

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23
Q

Describe the diverse genetic material of viruses

A
  • dsDNA
  • ssDNA
  • ssRNA
  • dsRNA
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24
Q

List the components of a prokaryotic cell

A
  1. Cell wall
  2. Capsule
  3. Cell membrane
  4. Cytoplasm
  5. Nucleoid
  6. Plasmid
  7. Flagellum
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25
Describe the components of a eukaryotic cell
1. Plasma cell membrane 2. Cytoplasm 3. Mitochondrion 4. SER 5. RER 6. Vacuole 7. Golgi 8. Nucleus 9. Nucleolus 10. Ribosomes 11. Microtubules 12. Centrosomes 13. Microfilaments 14. Lysosomes 15. Secretory vesicles 16. Peroxisomes 17. Chromatin 18. Intermediate filament
26
Describe bacteria
- single-celled microorganisms, diverse in shape and size - widely distributed in range of environments - cell wall usually contains peptidoglycan - cell membrane fatty acids bound to glycerol with ester bonds in lipid bilayers - glucose oxidation in glycolysis and Krebs cycle - many examples of photosynthesis
27
Components of peptidoglycan
- N-acetylmuramic acid - D-amino acids
28
Give an example of photosynthetic bacteria
Cyanobacteria
29
Describe archaea
- single called microorganisms, diverse in shape and size - characteristically found in extreme environments - cell walls of pseudopeptidoglycan, polysaccharides, glycoproteins, or proteins - membrane lipids of phytanyl groups hound to glycerol with ether bonds, in bilayers, monolayers, or mixture - glucose oxidation in glycolysis and Krebs cycle not described - oxygenic photosynthesis not described
30
Give examples of extreme environments where archaea might be found
- deep sea hydrothermal cents - hot springs - salt brine
31
Compare and contrast the reproduction of bacteria and archaea
Bacteria: binary fission, some produce spores Archaea: binary fission; sporulation not described
32
Compare and contrast the chromosomes of bacteria and archaea
Bacteria: usually a single circular chromosomes; introns not described Archaea: usually a single circular chromosome; introns may be present
33
Compare and contrast the flagella of bacteria and archaea
Bacteria: hollow, assembled by adding subunit a from a central pore to the tip Archaea: archella synthesised by adding subunits at the base
34
Archella
Archael flagella
35
Compare and contrast the tRNA of bacteria and archaea
Bacteria: thymine present Archaea: thymine absent
36
Compare and contrast the tmRNA of bacteria and archaea
Bacteria: tmRNA not described Archaea: described
37
Compare and contrast the RNA Polymerase of bacteria and archaea
Bacteria: simple, four polypeptides Archaea: complex, >8 polypeptides, may have multiple
38
Compare and contrast the pathogenicity of bacteria and archaea
Bacteria: many Archaea: none described
39
Early bacterial classification
1. Haeckel’s Monera (morphology) 2. Colony morphology 3. Staining (Gram)
40
What allowed the introduction of colony morphology classification
Microbiology culture
41
Describe Gram negative bacteria
- two membrane cell wall - thin layer of peptidoglycan
42
Describe Gram positive bacteria
- single cell membrane - thick peptidoglycan and teichoic acid layer layer
43
Give examples of eukaryotic microorganisms
1. Archaeplastida 2. Rhizaria 3. Chromoalveolata 4. Excavate 5. Amoebozoa 6. Opisthokonta
44
Describe Archaeplastida
Plants, red and green algae
45
Describe Rhizaria
Mostly heterotrophic unicellular organisms
46
Describe Chromoalveolata
- Stramenopiles, unicellular flagellates and diatoms - Alveolata
47
Describe Alveolata
- widespread group of predators and parasites - e.g. Paramecium
48
Describe Excavata
- mostly heterotrophs - some pathogenic - many anaerobic - Giardia, Trypanosoma
49
Describe Amoebozoa
Many forms of amoeba including Dictyostelium; slime moulds
50
Describe Opisthokonta
Fungi, animalia
51
How large is an amoeba?
150-400micrometres
52
How big is Giardia?
~10micrometres
53
Describe fungi
- can be micro/macroorganisme - eukaryotic - typically haploid nuclei - reproduce mainly with sexual and asexual spores - rigid chitin our cell walls - mostly filamentous growth form - heterotrophic
54
What is the fungal filament called?
Hypha
55
What is the fossil evidence of early bacterial life?
- stromatolites in carbonate sediments - Cyanobacteria - 3.4-3.5bn years ago (Archaen) - abundant in the Proterozoic (2.8-3GA)
56
Impacts of microorganisms on human society
1. Health 2. Agriculture 3. Food 4. Industry
57
Microorganisms in health
1. Microbiome 2. Morbidity and mortality
58
Microorganisms in agriculture
1. Leguminous plants 2. Nitrogen fixation 3. Ruminant microbiota in cattle and sheep 4. Disease
59
Microorganisms in food
1. Spoilage 2. Fermentation
60
Microorganisms in industry
1. Antibiotics 2. Enzymes 3. Chemicals 4. Harmful
61
Microbes on évolution
1. Symbiosis 2. Disease
62
Microbes interacting
1. Rhizosphère 2. Microbiome
63
Bacteria make up
- 70bn tonnes carbon - 12.8% total biomass
64
Fungi make up
- 12bn tonnes carbon - 2.2% total biomass
65
Archaea make up
- 8bn tonnes carbon - 1.5% total biomass
66
Protists make up
- 4bn tonnes carbon - 0.7% total biomass
67
Viruses make up
- 0.2bn tonnes carbon - 0.04% total biomass
68
Evolution of classification before molecular biology
1. System Naturae (Carl Linnaeus) 2. Tree of Life (Ernst Haeckel) 3. Two Empires (Édourd Chaton) 4. Four Kingdoms (Herbert Copeland) 5. Five Kingdoms (Robert Whittaker)
69
Describe the Systema Naturae
Cataloguing and naming, introduced the Latin binomial
70
Describe the Tree of Life
- based on morphological complexities, tissue system and nutrition - ideas of descent
71
Describe the Two Empires
eukaryotes and prokaryotes: cells with and without a nucleus
72
Describe the Four Kingdoms
Distinguished on cellular properties
73
Describe the Five Kingdoms
Cellular and nutritional characteristics
74
Describe rRNA
- accessible and tractable nucleic acid - structural component of the ribosome - functionally essential - highly conserved - relatively short (~1.5Kbp) - various amount organisms (though mostly at genus level)
75
Among bacterial 16S rRNAs, there are
- several universal conserved regions used to generate sequencing primers - nine variable regions used as phylogenetic signatures
76
How is rRNA characterised?
Thin layer chromatography sequencing
77
What does the endosymbiotic theory suffer
Mitochondria and chloroplasts are descended from specialised bacteria that survived endocytosis and became incorporated into the host cell
78
Extreme environments are
Rich in microbial life, and can support complex communities
79
Microbes
Dominate the biosphere
80
Problems with microscopy
- microscope bias - staining: we are looking at artefacts
81
Archaeal polymerases are
Much more like us
82
Which Gram is probably ancestral?
Negative
83
What is extreme depends upon
Your perspective - anthropocentrisme, animal-centric, eukaryote-centric

Michaelmas Term 1 (42 decks)

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